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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35768 91177308-0d34-0410-b5e6-96231b3b80d8
1979 lines
78 KiB
C++
1979 lines
78 KiB
C++
//===- SimplifyLibCalls.cpp - Optimize specific well-known library calls --===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by Reid Spencer and is distributed under the
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// University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements a module pass that applies a variety of small
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// optimizations for calls to specific well-known function calls (e.g. runtime
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// library functions). For example, a call to the function "exit(3)" that
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// occurs within the main() function can be transformed into a simple "return 3"
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// instruction. Any optimization that takes this form (replace call to library
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// function with simpler code that provides the same result) belongs in this
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// file.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "simplify-libcalls"
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#include "llvm/Constants.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Instructions.h"
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#include "llvm/Module.h"
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#include "llvm/Pass.h"
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#include "llvm/ADT/hash_map"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/Config/config.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Transforms/IPO.h"
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using namespace llvm;
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/// This statistic keeps track of the total number of library calls that have
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/// been simplified regardless of which call it is.
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STATISTIC(SimplifiedLibCalls, "Number of library calls simplified");
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namespace {
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// Forward declarations
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class LibCallOptimization;
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class SimplifyLibCalls;
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/// This list is populated by the constructor for LibCallOptimization class.
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/// Therefore all subclasses are registered here at static initialization time
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/// and this list is what the SimplifyLibCalls pass uses to apply the individual
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/// optimizations to the call sites.
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/// @brief The list of optimizations deriving from LibCallOptimization
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static LibCallOptimization *OptList = 0;
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/// This class is the abstract base class for the set of optimizations that
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/// corresponds to one library call. The SimplifyLibCalls pass will call the
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/// ValidateCalledFunction method to ask the optimization if a given Function
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/// is the kind that the optimization can handle. If the subclass returns true,
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/// then SImplifyLibCalls will also call the OptimizeCall method to perform,
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/// or attempt to perform, the optimization(s) for the library call. Otherwise,
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/// OptimizeCall won't be called. Subclasses are responsible for providing the
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/// name of the library call (strlen, strcpy, etc.) to the LibCallOptimization
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/// constructor. This is used to efficiently select which call instructions to
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/// optimize. The criteria for a "lib call" is "anything with well known
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/// semantics", typically a library function that is defined by an international
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/// standard. Because the semantics are well known, the optimizations can
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/// generally short-circuit actually calling the function if there's a simpler
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/// way (e.g. strlen(X) can be reduced to a constant if X is a constant global).
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/// @brief Base class for library call optimizations
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class VISIBILITY_HIDDEN LibCallOptimization {
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LibCallOptimization **Prev, *Next;
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const char *FunctionName; ///< Name of the library call we optimize
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#ifndef NDEBUG
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Statistic occurrences; ///< debug statistic (-debug-only=simplify-libcalls)
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#endif
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public:
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/// The \p fname argument must be the name of the library function being
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/// optimized by the subclass.
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/// @brief Constructor that registers the optimization.
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LibCallOptimization(const char *FName, const char *Description)
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: FunctionName(FName) {
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#ifndef NDEBUG
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occurrences.construct("simplify-libcalls", Description);
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#endif
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// Register this optimizer in the list of optimizations.
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Next = OptList;
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OptList = this;
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Prev = &OptList;
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if (Next) Next->Prev = &Next;
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}
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/// getNext - All libcall optimizations are chained together into a list,
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/// return the next one in the list.
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LibCallOptimization *getNext() { return Next; }
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/// @brief Deregister from the optlist
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virtual ~LibCallOptimization() {
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*Prev = Next;
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if (Next) Next->Prev = Prev;
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}
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/// The implementation of this function in subclasses should determine if
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/// \p F is suitable for the optimization. This method is called by
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/// SimplifyLibCalls::runOnModule to short circuit visiting all the call
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/// sites of such a function if that function is not suitable in the first
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/// place. If the called function is suitabe, this method should return true;
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/// false, otherwise. This function should also perform any lazy
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/// initialization that the LibCallOptimization needs to do, if its to return
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/// true. This avoids doing initialization until the optimizer is actually
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/// going to be called upon to do some optimization.
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/// @brief Determine if the function is suitable for optimization
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virtual bool ValidateCalledFunction(
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const Function* F, ///< The function that is the target of call sites
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SimplifyLibCalls& SLC ///< The pass object invoking us
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) = 0;
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/// The implementations of this function in subclasses is the heart of the
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/// SimplifyLibCalls algorithm. Sublcasses of this class implement
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/// OptimizeCall to determine if (a) the conditions are right for optimizing
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/// the call and (b) to perform the optimization. If an action is taken
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/// against ci, the subclass is responsible for returning true and ensuring
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/// that ci is erased from its parent.
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/// @brief Optimize a call, if possible.
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virtual bool OptimizeCall(
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CallInst* ci, ///< The call instruction that should be optimized.
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SimplifyLibCalls& SLC ///< The pass object invoking us
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) = 0;
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/// @brief Get the name of the library call being optimized
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const char *getFunctionName() const { return FunctionName; }
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bool ReplaceCallWith(CallInst *CI, Value *V) {
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if (!CI->use_empty())
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CI->replaceAllUsesWith(V);
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CI->eraseFromParent();
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return true;
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}
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/// @brief Called by SimplifyLibCalls to update the occurrences statistic.
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void succeeded() {
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#ifndef NDEBUG
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DEBUG(++occurrences);
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#endif
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}
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};
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/// This class is an LLVM Pass that applies each of the LibCallOptimization
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/// instances to all the call sites in a module, relatively efficiently. The
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/// purpose of this pass is to provide optimizations for calls to well-known
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/// functions with well-known semantics, such as those in the c library. The
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/// class provides the basic infrastructure for handling runOnModule. Whenever
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/// this pass finds a function call, it asks the appropriate optimizer to
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/// validate the call (ValidateLibraryCall). If it is validated, then
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/// the OptimizeCall method is also called.
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/// @brief A ModulePass for optimizing well-known function calls.
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class VISIBILITY_HIDDEN SimplifyLibCalls : public ModulePass {
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public:
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/// We need some target data for accurate signature details that are
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/// target dependent. So we require target data in our AnalysisUsage.
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/// @brief Require TargetData from AnalysisUsage.
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virtual void getAnalysisUsage(AnalysisUsage& Info) const {
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// Ask that the TargetData analysis be performed before us so we can use
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// the target data.
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Info.addRequired<TargetData>();
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}
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/// For this pass, process all of the function calls in the module, calling
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/// ValidateLibraryCall and OptimizeCall as appropriate.
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/// @brief Run all the lib call optimizations on a Module.
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virtual bool runOnModule(Module &M) {
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reset(M);
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bool result = false;
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hash_map<std::string, LibCallOptimization*> OptznMap;
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for (LibCallOptimization *Optzn = OptList; Optzn; Optzn = Optzn->getNext())
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OptznMap[Optzn->getFunctionName()] = Optzn;
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// The call optimizations can be recursive. That is, the optimization might
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// generate a call to another function which can also be optimized. This way
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// we make the LibCallOptimization instances very specific to the case they
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// handle. It also means we need to keep running over the function calls in
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// the module until we don't get any more optimizations possible.
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bool found_optimization = false;
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do {
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found_optimization = false;
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for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI) {
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// All the "well-known" functions are external and have external linkage
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// because they live in a runtime library somewhere and were (probably)
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// not compiled by LLVM. So, we only act on external functions that
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// have external or dllimport linkage and non-empty uses.
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if (!FI->isDeclaration() ||
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!(FI->hasExternalLinkage() || FI->hasDLLImportLinkage()) ||
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FI->use_empty())
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continue;
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// Get the optimization class that pertains to this function
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hash_map<std::string, LibCallOptimization*>::iterator OMI =
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OptznMap.find(FI->getName());
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if (OMI == OptznMap.end()) continue;
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LibCallOptimization *CO = OMI->second;
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// Make sure the called function is suitable for the optimization
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if (!CO->ValidateCalledFunction(FI, *this))
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continue;
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// Loop over each of the uses of the function
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for (Value::use_iterator UI = FI->use_begin(), UE = FI->use_end();
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UI != UE ; ) {
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// If the use of the function is a call instruction
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if (CallInst* CI = dyn_cast<CallInst>(*UI++)) {
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// Do the optimization on the LibCallOptimization.
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if (CO->OptimizeCall(CI, *this)) {
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++SimplifiedLibCalls;
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found_optimization = result = true;
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CO->succeeded();
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}
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}
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}
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}
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} while (found_optimization);
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return result;
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}
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/// @brief Return the *current* module we're working on.
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Module* getModule() const { return M; }
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/// @brief Return the *current* target data for the module we're working on.
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TargetData* getTargetData() const { return TD; }
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/// @brief Return the size_t type -- syntactic shortcut
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const Type* getIntPtrType() const { return TD->getIntPtrType(); }
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/// @brief Return a Function* for the putchar libcall
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Constant *get_putchar() {
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if (!putchar_func)
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putchar_func =
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M->getOrInsertFunction("putchar", Type::Int32Ty, Type::Int32Ty, NULL);
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return putchar_func;
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}
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/// @brief Return a Function* for the puts libcall
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Constant *get_puts() {
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if (!puts_func)
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puts_func = M->getOrInsertFunction("puts", Type::Int32Ty,
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PointerType::get(Type::Int8Ty),
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NULL);
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return puts_func;
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}
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/// @brief Return a Function* for the fputc libcall
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Constant *get_fputc(const Type* FILEptr_type) {
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if (!fputc_func)
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fputc_func = M->getOrInsertFunction("fputc", Type::Int32Ty, Type::Int32Ty,
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FILEptr_type, NULL);
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return fputc_func;
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}
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/// @brief Return a Function* for the fputs libcall
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Constant *get_fputs(const Type* FILEptr_type) {
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if (!fputs_func)
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fputs_func = M->getOrInsertFunction("fputs", Type::Int32Ty,
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PointerType::get(Type::Int8Ty),
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FILEptr_type, NULL);
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return fputs_func;
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}
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/// @brief Return a Function* for the fwrite libcall
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Constant *get_fwrite(const Type* FILEptr_type) {
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if (!fwrite_func)
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fwrite_func = M->getOrInsertFunction("fwrite", TD->getIntPtrType(),
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PointerType::get(Type::Int8Ty),
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TD->getIntPtrType(),
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TD->getIntPtrType(),
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FILEptr_type, NULL);
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return fwrite_func;
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}
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/// @brief Return a Function* for the sqrt libcall
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Constant *get_sqrt() {
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if (!sqrt_func)
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sqrt_func = M->getOrInsertFunction("sqrt", Type::DoubleTy,
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Type::DoubleTy, NULL);
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return sqrt_func;
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}
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/// @brief Return a Function* for the strcpy libcall
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Constant *get_strcpy() {
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if (!strcpy_func)
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strcpy_func = M->getOrInsertFunction("strcpy",
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PointerType::get(Type::Int8Ty),
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PointerType::get(Type::Int8Ty),
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PointerType::get(Type::Int8Ty),
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NULL);
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return strcpy_func;
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}
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/// @brief Return a Function* for the strlen libcall
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Constant *get_strlen() {
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if (!strlen_func)
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strlen_func = M->getOrInsertFunction("strlen", TD->getIntPtrType(),
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PointerType::get(Type::Int8Ty),
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NULL);
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return strlen_func;
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}
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/// @brief Return a Function* for the memchr libcall
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Constant *get_memchr() {
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if (!memchr_func)
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memchr_func = M->getOrInsertFunction("memchr",
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PointerType::get(Type::Int8Ty),
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PointerType::get(Type::Int8Ty),
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Type::Int32Ty, TD->getIntPtrType(),
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NULL);
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return memchr_func;
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}
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/// @brief Return a Function* for the memcpy libcall
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Constant *get_memcpy() {
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if (!memcpy_func) {
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const Type *SBP = PointerType::get(Type::Int8Ty);
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const char *N = TD->getIntPtrType() == Type::Int32Ty ?
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"llvm.memcpy.i32" : "llvm.memcpy.i64";
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memcpy_func = M->getOrInsertFunction(N, Type::VoidTy, SBP, SBP,
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TD->getIntPtrType(), Type::Int32Ty,
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NULL);
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}
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return memcpy_func;
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}
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Constant *getUnaryFloatFunction(const char *Name, Constant *&Cache) {
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if (!Cache)
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Cache = M->getOrInsertFunction(Name, Type::FloatTy, Type::FloatTy, NULL);
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return Cache;
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}
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Constant *get_floorf() { return getUnaryFloatFunction("floorf", floorf_func);}
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Constant *get_ceilf() { return getUnaryFloatFunction( "ceilf", ceilf_func);}
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Constant *get_roundf() { return getUnaryFloatFunction("roundf", roundf_func);}
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Constant *get_rintf() { return getUnaryFloatFunction( "rintf", rintf_func);}
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Constant *get_nearbyintf() { return getUnaryFloatFunction("nearbyintf",
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nearbyintf_func); }
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private:
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/// @brief Reset our cached data for a new Module
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void reset(Module& mod) {
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M = &mod;
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TD = &getAnalysis<TargetData>();
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putchar_func = 0;
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puts_func = 0;
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fputc_func = 0;
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fputs_func = 0;
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fwrite_func = 0;
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memcpy_func = 0;
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memchr_func = 0;
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sqrt_func = 0;
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strcpy_func = 0;
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strlen_func = 0;
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floorf_func = 0;
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ceilf_func = 0;
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roundf_func = 0;
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rintf_func = 0;
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nearbyintf_func = 0;
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}
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private:
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/// Caches for function pointers.
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Constant *putchar_func, *puts_func;
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Constant *fputc_func, *fputs_func, *fwrite_func;
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Constant *memcpy_func, *memchr_func;
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Constant *sqrt_func;
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Constant *strcpy_func, *strlen_func;
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Constant *floorf_func, *ceilf_func, *roundf_func;
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Constant *rintf_func, *nearbyintf_func;
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Module *M; ///< Cached Module
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TargetData *TD; ///< Cached TargetData
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};
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// Register the pass
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RegisterPass<SimplifyLibCalls>
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X("simplify-libcalls", "Simplify well-known library calls");
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} // anonymous namespace
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// The only public symbol in this file which just instantiates the pass object
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ModulePass *llvm::createSimplifyLibCallsPass() {
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return new SimplifyLibCalls();
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}
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// Classes below here, in the anonymous namespace, are all subclasses of the
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// LibCallOptimization class, each implementing all optimizations possible for a
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// single well-known library call. Each has a static singleton instance that
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// auto registers it into the "optlist" global above.
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namespace {
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// Forward declare utility functions.
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static bool GetConstantStringInfo(Value *V, std::string &Str);
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static Value *CastToCStr(Value *V, Instruction *IP);
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/// This LibCallOptimization will find instances of a call to "exit" that occurs
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/// within the "main" function and change it to a simple "ret" instruction with
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/// the same value passed to the exit function. When this is done, it splits the
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/// basic block at the exit(3) call and deletes the call instruction.
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/// @brief Replace calls to exit in main with a simple return
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struct VISIBILITY_HIDDEN ExitInMainOptimization : public LibCallOptimization {
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ExitInMainOptimization() : LibCallOptimization("exit",
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"Number of 'exit' calls simplified") {}
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// Make sure the called function looks like exit (int argument, int return
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// type, external linkage, not varargs).
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virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
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return F->arg_size() >= 1 && F->arg_begin()->getType()->isInteger();
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}
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virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
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// To be careful, we check that the call to exit is coming from "main", that
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// main has external linkage, and the return type of main and the argument
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// to exit have the same type.
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Function *from = ci->getParent()->getParent();
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if (from->hasExternalLinkage())
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if (from->getReturnType() == ci->getOperand(1)->getType())
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if (from->getName() == "main") {
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// Okay, time to actually do the optimization. First, get the basic
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// block of the call instruction
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BasicBlock* bb = ci->getParent();
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// Create a return instruction that we'll replace the call with.
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// Note that the argument of the return is the argument of the call
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// instruction.
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new ReturnInst(ci->getOperand(1), ci);
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// Split the block at the call instruction which places it in a new
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// basic block.
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bb->splitBasicBlock(ci);
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// The block split caused a branch instruction to be inserted into
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// the end of the original block, right after the return instruction
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// that we put there. That's not a valid block, so delete the branch
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// instruction.
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bb->getInstList().pop_back();
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// Now we can finally get rid of the call instruction which now lives
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// in the new basic block.
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ci->eraseFromParent();
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// Optimization succeeded, return true.
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return true;
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}
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// We didn't pass the criteria for this optimization so return false
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return false;
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}
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} ExitInMainOptimizer;
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/// This LibCallOptimization will simplify a call to the strcat library
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/// function. The simplification is possible only if the string being
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/// concatenated is a constant array or a constant expression that results in
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/// a constant string. In this case we can replace it with strlen + llvm.memcpy
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/// of the constant string. Both of these calls are further reduced, if possible
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/// on subsequent passes.
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/// @brief Simplify the strcat library function.
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struct VISIBILITY_HIDDEN StrCatOptimization : public LibCallOptimization {
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public:
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/// @brief Default constructor
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StrCatOptimization() : LibCallOptimization("strcat",
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"Number of 'strcat' calls simplified") {}
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public:
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/// @brief Make sure that the "strcat" function has the right prototype
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virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
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const FunctionType *FT = F->getFunctionType();
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return FT->getNumParams() == 2 &&
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|
FT->getReturnType() == PointerType::get(Type::Int8Ty) &&
|
|
FT->getParamType(0) == FT->getReturnType() &&
|
|
FT->getParamType(1) == FT->getReturnType();
|
|
}
|
|
|
|
/// @brief Optimize the strcat library function
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
// Extract some information from the instruction
|
|
Value *Dst = CI->getOperand(1);
|
|
Value *Src = CI->getOperand(2);
|
|
|
|
// Extract the initializer (while making numerous checks) from the
|
|
// source operand of the call to strcat.
|
|
std::string SrcStr;
|
|
if (!GetConstantStringInfo(Src, SrcStr))
|
|
return false;
|
|
|
|
// Handle the simple, do-nothing case
|
|
if (SrcStr.empty())
|
|
return ReplaceCallWith(CI, Dst);
|
|
|
|
// We need to find the end of the destination string. That's where the
|
|
// memory is to be moved to. We just generate a call to strlen.
|
|
CallInst *DstLen = new CallInst(SLC.get_strlen(), Dst,
|
|
Dst->getName()+".len", CI);
|
|
|
|
// Now that we have the destination's length, we must index into the
|
|
// destination's pointer to get the actual memcpy destination (end of
|
|
// the string .. we're concatenating).
|
|
Dst = new GetElementPtrInst(Dst, DstLen, Dst->getName()+".indexed", CI);
|
|
|
|
// We have enough information to now generate the memcpy call to
|
|
// do the concatenation for us.
|
|
Value *Vals[] = {
|
|
Dst, Src,
|
|
ConstantInt::get(SLC.getIntPtrType(), SrcStr.size()+1), // copy nul byte.
|
|
ConstantInt::get(Type::Int32Ty, 1) // alignment
|
|
};
|
|
new CallInst(SLC.get_memcpy(), Vals, 4, "", CI);
|
|
|
|
return ReplaceCallWith(CI, Dst);
|
|
}
|
|
} StrCatOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify a call to the strchr library
|
|
/// function. It optimizes out cases where the arguments are both constant
|
|
/// and the result can be determined statically.
|
|
/// @brief Simplify the strcmp library function.
|
|
struct VISIBILITY_HIDDEN StrChrOptimization : public LibCallOptimization {
|
|
public:
|
|
StrChrOptimization() : LibCallOptimization("strchr",
|
|
"Number of 'strchr' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "strchr" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
|
|
const FunctionType *FT = F->getFunctionType();
|
|
return FT->getNumParams() == 2 &&
|
|
FT->getReturnType() == PointerType::get(Type::Int8Ty) &&
|
|
FT->getParamType(0) == FT->getReturnType() &&
|
|
isa<IntegerType>(FT->getParamType(1));
|
|
}
|
|
|
|
/// @brief Perform the strchr optimizations
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
// Check that the first argument to strchr is a constant array of sbyte.
|
|
std::string Str;
|
|
if (!GetConstantStringInfo(CI->getOperand(1), Str))
|
|
return false;
|
|
|
|
// If the second operand is not constant, just lower this to memchr since we
|
|
// know the length of the input string.
|
|
ConstantInt *CSI = dyn_cast<ConstantInt>(CI->getOperand(2));
|
|
if (!CSI) {
|
|
Value *Args[3] = {
|
|
CI->getOperand(1),
|
|
CI->getOperand(2),
|
|
ConstantInt::get(SLC.getIntPtrType(), Str.size()+1)
|
|
};
|
|
return ReplaceCallWith(CI, new CallInst(SLC.get_memchr(), Args, 3,
|
|
CI->getName(), CI));
|
|
}
|
|
|
|
// strchr can find the nul character.
|
|
Str += '\0';
|
|
|
|
// Get the character we're looking for
|
|
char CharValue = CSI->getSExtValue();
|
|
|
|
// Compute the offset
|
|
uint64_t i = 0;
|
|
while (1) {
|
|
if (i == Str.size()) // Didn't find the char. strchr returns null.
|
|
return ReplaceCallWith(CI, Constant::getNullValue(CI->getType()));
|
|
// Did we find our match?
|
|
if (Str[i] == CharValue)
|
|
break;
|
|
++i;
|
|
}
|
|
|
|
// strchr(s+n,c) -> gep(s+n+i,c)
|
|
// (if c is a constant integer and s is a constant string)
|
|
Value *Idx = ConstantInt::get(Type::Int64Ty, i);
|
|
Value *GEP = new GetElementPtrInst(CI->getOperand(1), Idx,
|
|
CI->getOperand(1)->getName() +
|
|
".strchr", CI);
|
|
return ReplaceCallWith(CI, GEP);
|
|
}
|
|
} StrChrOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify a call to the strcmp library
|
|
/// function. It optimizes out cases where one or both arguments are constant
|
|
/// and the result can be determined statically.
|
|
/// @brief Simplify the strcmp library function.
|
|
struct VISIBILITY_HIDDEN StrCmpOptimization : public LibCallOptimization {
|
|
public:
|
|
StrCmpOptimization() : LibCallOptimization("strcmp",
|
|
"Number of 'strcmp' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "strcmp" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
|
|
const FunctionType *FT = F->getFunctionType();
|
|
return FT->getReturnType() == Type::Int32Ty && FT->getNumParams() == 2 &&
|
|
FT->getParamType(0) == FT->getParamType(1) &&
|
|
FT->getParamType(0) == PointerType::get(Type::Int8Ty);
|
|
}
|
|
|
|
/// @brief Perform the strcmp optimization
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
// First, check to see if src and destination are the same. If they are,
|
|
// then the optimization is to replace the CallInst with a constant 0
|
|
// because the call is a no-op.
|
|
Value *Str1P = CI->getOperand(1);
|
|
Value *Str2P = CI->getOperand(2);
|
|
if (Str1P == Str2P) // strcmp(x,x) -> 0
|
|
return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
|
|
|
|
std::string Str1;
|
|
if (!GetConstantStringInfo(Str1P, Str1))
|
|
return false;
|
|
if (Str1.empty()) {
|
|
// strcmp("", x) -> *x
|
|
Value *V = new LoadInst(Str2P, CI->getName()+".load", CI);
|
|
V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
|
|
return ReplaceCallWith(CI, V);
|
|
}
|
|
|
|
std::string Str2;
|
|
if (!GetConstantStringInfo(Str2P, Str2))
|
|
return false;
|
|
if (Str2.empty()) {
|
|
// strcmp(x,"") -> *x
|
|
Value *V = new LoadInst(Str1P, CI->getName()+".load", CI);
|
|
V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
|
|
return ReplaceCallWith(CI, V);
|
|
}
|
|
|
|
// strcmp(x, y) -> cnst (if both x and y are constant strings)
|
|
int R = strcmp(Str1.c_str(), Str2.c_str());
|
|
return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), R));
|
|
}
|
|
} StrCmpOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify a call to the strncmp library
|
|
/// function. It optimizes out cases where one or both arguments are constant
|
|
/// and the result can be determined statically.
|
|
/// @brief Simplify the strncmp library function.
|
|
struct VISIBILITY_HIDDEN StrNCmpOptimization : public LibCallOptimization {
|
|
public:
|
|
StrNCmpOptimization() : LibCallOptimization("strncmp",
|
|
"Number of 'strncmp' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "strncmp" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
|
|
const FunctionType *FT = F->getFunctionType();
|
|
return FT->getReturnType() == Type::Int32Ty && FT->getNumParams() == 3 &&
|
|
FT->getParamType(0) == FT->getParamType(1) &&
|
|
FT->getParamType(0) == PointerType::get(Type::Int8Ty) &&
|
|
isa<IntegerType>(FT->getParamType(2));
|
|
return false;
|
|
}
|
|
|
|
/// @brief Perform the strncmp optimization
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
// First, check to see if src and destination are the same. If they are,
|
|
// then the optimization is to replace the CallInst with a constant 0
|
|
// because the call is a no-op.
|
|
Value *Str1P = CI->getOperand(1);
|
|
Value *Str2P = CI->getOperand(2);
|
|
if (Str1P == Str2P) // strncmp(x,x, n) -> 0
|
|
return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
|
|
|
|
// Check the length argument, if it is Constant zero then the strings are
|
|
// considered equal.
|
|
uint64_t Length;
|
|
if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getOperand(3)))
|
|
Length = LengthArg->getZExtValue();
|
|
else
|
|
return false;
|
|
|
|
if (Length == 0) // strncmp(x,y,0) -> 0
|
|
return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
|
|
|
|
std::string Str1;
|
|
if (!GetConstantStringInfo(Str1P, Str1))
|
|
return false;
|
|
if (Str1.empty()) {
|
|
// strncmp("", x, n) -> *x
|
|
Value *V = new LoadInst(Str2P, CI->getName()+".load", CI);
|
|
V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
|
|
return ReplaceCallWith(CI, V);
|
|
}
|
|
|
|
std::string Str2;
|
|
if (!GetConstantStringInfo(Str2P, Str2))
|
|
return false;
|
|
if (Str2.empty()) {
|
|
// strncmp(x, "", n) -> *x
|
|
Value *V = new LoadInst(Str1P, CI->getName()+".load", CI);
|
|
V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
|
|
return ReplaceCallWith(CI, V);
|
|
}
|
|
|
|
// strncmp(x, y, n) -> cnst (if both x and y are constant strings)
|
|
int R = strncmp(Str1.c_str(), Str2.c_str(), Length);
|
|
return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), R));
|
|
}
|
|
} StrNCmpOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify a call to the strcpy library
|
|
/// function. Two optimizations are possible:
|
|
/// (1) If src and dest are the same and not volatile, just return dest
|
|
/// (2) If the src is a constant then we can convert to llvm.memmove
|
|
/// @brief Simplify the strcpy library function.
|
|
struct VISIBILITY_HIDDEN StrCpyOptimization : public LibCallOptimization {
|
|
public:
|
|
StrCpyOptimization() : LibCallOptimization("strcpy",
|
|
"Number of 'strcpy' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "strcpy" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
|
|
const FunctionType *FT = F->getFunctionType();
|
|
return FT->getNumParams() == 2 &&
|
|
FT->getParamType(0) == FT->getParamType(1) &&
|
|
FT->getReturnType() == FT->getParamType(0) &&
|
|
FT->getParamType(0) == PointerType::get(Type::Int8Ty);
|
|
}
|
|
|
|
/// @brief Perform the strcpy optimization
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
// First, check to see if src and destination are the same. If they are,
|
|
// then the optimization is to replace the CallInst with the destination
|
|
// because the call is a no-op. Note that this corresponds to the
|
|
// degenerate strcpy(X,X) case which should have "undefined" results
|
|
// according to the C specification. However, it occurs sometimes and
|
|
// we optimize it as a no-op.
|
|
Value *Dst = CI->getOperand(1);
|
|
Value *Src = CI->getOperand(2);
|
|
if (Dst == Src) {
|
|
// strcpy(x, x) -> x
|
|
return ReplaceCallWith(CI, Dst);
|
|
}
|
|
|
|
// Get the length of the constant string referenced by the Src operand.
|
|
std::string SrcStr;
|
|
if (!GetConstantStringInfo(Src, SrcStr))
|
|
return false;
|
|
|
|
// If the constant string's length is zero we can optimize this by just
|
|
// doing a store of 0 at the first byte of the destination
|
|
if (SrcStr.size() == 0) {
|
|
new StoreInst(ConstantInt::get(Type::Int8Ty, 0), Dst, CI);
|
|
return ReplaceCallWith(CI, Dst);
|
|
}
|
|
|
|
// We have enough information to now generate the memcpy call to
|
|
// do the concatenation for us.
|
|
Value *MemcpyOps[] = {
|
|
Dst, Src, // Pass length including nul byte.
|
|
ConstantInt::get(SLC.getIntPtrType(), SrcStr.size()+1),
|
|
ConstantInt::get(Type::Int32Ty, 1) // alignment
|
|
};
|
|
new CallInst(SLC.get_memcpy(), MemcpyOps, 4, "", CI);
|
|
|
|
return ReplaceCallWith(CI, Dst);
|
|
}
|
|
} StrCpyOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify a call to the strlen library
|
|
/// function by replacing it with a constant value if the string provided to
|
|
/// it is a constant array.
|
|
/// @brief Simplify the strlen library function.
|
|
struct VISIBILITY_HIDDEN StrLenOptimization : public LibCallOptimization {
|
|
StrLenOptimization() : LibCallOptimization("strlen",
|
|
"Number of 'strlen' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "strlen" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
|
|
const FunctionType *FT = F->getFunctionType();
|
|
return FT->getNumParams() == 1 &&
|
|
FT->getParamType(0) == PointerType::get(Type::Int8Ty) &&
|
|
isa<IntegerType>(FT->getReturnType());
|
|
}
|
|
|
|
/// @brief Perform the strlen optimization
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
// Make sure we're dealing with an sbyte* here.
|
|
Value *Src = CI->getOperand(1);
|
|
|
|
// Does the call to strlen have exactly one use?
|
|
if (CI->hasOneUse()) {
|
|
// Is that single use a icmp operator?
|
|
if (ICmpInst *Cmp = dyn_cast<ICmpInst>(CI->use_back()))
|
|
// Is it compared against a constant integer?
|
|
if (ConstantInt *Cst = dyn_cast<ConstantInt>(Cmp->getOperand(1))) {
|
|
// If its compared against length 0 with == or !=
|
|
if (Cst->getZExtValue() == 0 && Cmp->isEquality()) {
|
|
// strlen(x) != 0 -> *x != 0
|
|
// strlen(x) == 0 -> *x == 0
|
|
Value *V = new LoadInst(Src, Src->getName()+".first", CI);
|
|
V = new ICmpInst(Cmp->getPredicate(), V,
|
|
ConstantInt::get(Type::Int8Ty, 0),
|
|
Cmp->getName()+".strlen", CI);
|
|
Cmp->replaceAllUsesWith(V);
|
|
Cmp->eraseFromParent();
|
|
return ReplaceCallWith(CI, 0); // no uses.
|
|
}
|
|
}
|
|
}
|
|
|
|
// Get the length of the constant string operand
|
|
std::string Str;
|
|
if (!GetConstantStringInfo(Src, Str))
|
|
return false;
|
|
|
|
// strlen("xyz") -> 3 (for example)
|
|
return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), Str.size()));
|
|
}
|
|
} StrLenOptimizer;
|
|
|
|
/// IsOnlyUsedInEqualsComparison - Return true if it only matters that the value
|
|
/// is equal or not-equal to zero.
|
|
static bool IsOnlyUsedInEqualsZeroComparison(Instruction *I) {
|
|
for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
|
|
UI != E; ++UI) {
|
|
if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
|
|
if (IC->isEquality())
|
|
if (Constant *C = dyn_cast<Constant>(IC->getOperand(1)))
|
|
if (C->isNullValue())
|
|
continue;
|
|
// Unknown instruction.
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/// This memcmpOptimization will simplify a call to the memcmp library
|
|
/// function.
|
|
struct VISIBILITY_HIDDEN memcmpOptimization : public LibCallOptimization {
|
|
/// @brief Default Constructor
|
|
memcmpOptimization()
|
|
: LibCallOptimization("memcmp", "Number of 'memcmp' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "memcmp" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &TD) {
|
|
Function::const_arg_iterator AI = F->arg_begin();
|
|
if (F->arg_size() != 3 || !isa<PointerType>(AI->getType())) return false;
|
|
if (!isa<PointerType>((++AI)->getType())) return false;
|
|
if (!(++AI)->getType()->isInteger()) return false;
|
|
if (!F->getReturnType()->isInteger()) return false;
|
|
return true;
|
|
}
|
|
|
|
/// Because of alignment and instruction information that we don't have, we
|
|
/// leave the bulk of this to the code generators.
|
|
///
|
|
/// Note that we could do much more if we could force alignment on otherwise
|
|
/// small aligned allocas, or if we could indicate that loads have a small
|
|
/// alignment.
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &TD) {
|
|
Value *LHS = CI->getOperand(1), *RHS = CI->getOperand(2);
|
|
|
|
// If the two operands are the same, return zero.
|
|
if (LHS == RHS) {
|
|
// memcmp(s,s,x) -> 0
|
|
return ReplaceCallWith(CI, Constant::getNullValue(CI->getType()));
|
|
}
|
|
|
|
// Make sure we have a constant length.
|
|
ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getOperand(3));
|
|
if (!LenC) return false;
|
|
uint64_t Len = LenC->getZExtValue();
|
|
|
|
// If the length is zero, this returns 0.
|
|
switch (Len) {
|
|
case 0:
|
|
// memcmp(s1,s2,0) -> 0
|
|
return ReplaceCallWith(CI, Constant::getNullValue(CI->getType()));
|
|
case 1: {
|
|
// memcmp(S1,S2,1) -> *(ubyte*)S1 - *(ubyte*)S2
|
|
const Type *UCharPtr = PointerType::get(Type::Int8Ty);
|
|
CastInst *Op1Cast = CastInst::create(
|
|
Instruction::BitCast, LHS, UCharPtr, LHS->getName(), CI);
|
|
CastInst *Op2Cast = CastInst::create(
|
|
Instruction::BitCast, RHS, UCharPtr, RHS->getName(), CI);
|
|
Value *S1V = new LoadInst(Op1Cast, LHS->getName()+".val", CI);
|
|
Value *S2V = new LoadInst(Op2Cast, RHS->getName()+".val", CI);
|
|
Value *RV = BinaryOperator::createSub(S1V, S2V, CI->getName()+".diff",CI);
|
|
if (RV->getType() != CI->getType())
|
|
RV = CastInst::createIntegerCast(RV, CI->getType(), false,
|
|
RV->getName(), CI);
|
|
return ReplaceCallWith(CI, RV);
|
|
}
|
|
case 2:
|
|
if (IsOnlyUsedInEqualsZeroComparison(CI)) {
|
|
// TODO: IF both are aligned, use a short load/compare.
|
|
|
|
// memcmp(S1,S2,2) -> S1[0]-S2[0] | S1[1]-S2[1] iff only ==/!= 0 matters
|
|
const Type *UCharPtr = PointerType::get(Type::Int8Ty);
|
|
CastInst *Op1Cast = CastInst::create(
|
|
Instruction::BitCast, LHS, UCharPtr, LHS->getName(), CI);
|
|
CastInst *Op2Cast = CastInst::create(
|
|
Instruction::BitCast, RHS, UCharPtr, RHS->getName(), CI);
|
|
Value *S1V1 = new LoadInst(Op1Cast, LHS->getName()+".val1", CI);
|
|
Value *S2V1 = new LoadInst(Op2Cast, RHS->getName()+".val1", CI);
|
|
Value *D1 = BinaryOperator::createSub(S1V1, S2V1,
|
|
CI->getName()+".d1", CI);
|
|
Constant *One = ConstantInt::get(Type::Int32Ty, 1);
|
|
Value *G1 = new GetElementPtrInst(Op1Cast, One, "next1v", CI);
|
|
Value *G2 = new GetElementPtrInst(Op2Cast, One, "next2v", CI);
|
|
Value *S1V2 = new LoadInst(G1, LHS->getName()+".val2", CI);
|
|
Value *S2V2 = new LoadInst(G2, RHS->getName()+".val2", CI);
|
|
Value *D2 = BinaryOperator::createSub(S1V2, S2V2,
|
|
CI->getName()+".d1", CI);
|
|
Value *Or = BinaryOperator::createOr(D1, D2, CI->getName()+".res", CI);
|
|
if (Or->getType() != CI->getType())
|
|
Or = CastInst::createIntegerCast(Or, CI->getType(), false /*ZExt*/,
|
|
Or->getName(), CI);
|
|
return ReplaceCallWith(CI, Or);
|
|
}
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
} memcmpOptimizer;
|
|
|
|
|
|
/// This LibCallOptimization will simplify a call to the memcpy library
|
|
/// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
|
|
/// bytes depending on the length of the string and the alignment. Additional
|
|
/// optimizations are possible in code generation (sequence of immediate store)
|
|
/// @brief Simplify the memcpy library function.
|
|
struct VISIBILITY_HIDDEN LLVMMemCpyMoveOptzn : public LibCallOptimization {
|
|
LLVMMemCpyMoveOptzn(const char* fname, const char* desc)
|
|
: LibCallOptimization(fname, desc) {}
|
|
|
|
/// @brief Make sure that the "memcpy" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& TD) {
|
|
// Just make sure this has 4 arguments per LLVM spec.
|
|
return (f->arg_size() == 4);
|
|
}
|
|
|
|
/// Because of alignment and instruction information that we don't have, we
|
|
/// leave the bulk of this to the code generators. The optimization here just
|
|
/// deals with a few degenerate cases where the length of the string and the
|
|
/// alignment match the sizes of our intrinsic types so we can do a load and
|
|
/// store instead of the memcpy call.
|
|
/// @brief Perform the memcpy optimization.
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& TD) {
|
|
// Make sure we have constant int values to work with
|
|
ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
|
|
if (!LEN)
|
|
return false;
|
|
ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
|
|
if (!ALIGN)
|
|
return false;
|
|
|
|
// If the length is larger than the alignment, we can't optimize
|
|
uint64_t len = LEN->getZExtValue();
|
|
uint64_t alignment = ALIGN->getZExtValue();
|
|
if (alignment == 0)
|
|
alignment = 1; // Alignment 0 is identity for alignment 1
|
|
if (len > alignment)
|
|
return false;
|
|
|
|
// Get the type we will cast to, based on size of the string
|
|
Value* dest = ci->getOperand(1);
|
|
Value* src = ci->getOperand(2);
|
|
const Type* castType = 0;
|
|
switch (len) {
|
|
case 0:
|
|
// memcpy(d,s,0,a) -> d
|
|
return ReplaceCallWith(ci, 0);
|
|
case 1: castType = Type::Int8Ty; break;
|
|
case 2: castType = Type::Int16Ty; break;
|
|
case 4: castType = Type::Int32Ty; break;
|
|
case 8: castType = Type::Int64Ty; break;
|
|
default:
|
|
return false;
|
|
}
|
|
|
|
// Cast source and dest to the right sized primitive and then load/store
|
|
CastInst* SrcCast = CastInst::create(Instruction::BitCast,
|
|
src, PointerType::get(castType), src->getName()+".cast", ci);
|
|
CastInst* DestCast = CastInst::create(Instruction::BitCast,
|
|
dest, PointerType::get(castType),dest->getName()+".cast", ci);
|
|
LoadInst* LI = new LoadInst(SrcCast,SrcCast->getName()+".val",ci);
|
|
new StoreInst(LI, DestCast, ci);
|
|
return ReplaceCallWith(ci, 0);
|
|
}
|
|
};
|
|
|
|
/// This LibCallOptimization will simplify a call to the memcpy/memmove library
|
|
/// functions.
|
|
LLVMMemCpyMoveOptzn LLVMMemCpyOptimizer32("llvm.memcpy.i32",
|
|
"Number of 'llvm.memcpy' calls simplified");
|
|
LLVMMemCpyMoveOptzn LLVMMemCpyOptimizer64("llvm.memcpy.i64",
|
|
"Number of 'llvm.memcpy' calls simplified");
|
|
LLVMMemCpyMoveOptzn LLVMMemMoveOptimizer32("llvm.memmove.i32",
|
|
"Number of 'llvm.memmove' calls simplified");
|
|
LLVMMemCpyMoveOptzn LLVMMemMoveOptimizer64("llvm.memmove.i64",
|
|
"Number of 'llvm.memmove' calls simplified");
|
|
|
|
/// This LibCallOptimization will simplify a call to the memset library
|
|
/// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
|
|
/// bytes depending on the length argument.
|
|
struct VISIBILITY_HIDDEN LLVMMemSetOptimization : public LibCallOptimization {
|
|
/// @brief Default Constructor
|
|
LLVMMemSetOptimization(const char *Name) : LibCallOptimization(Name,
|
|
"Number of 'llvm.memset' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "memset" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &TD) {
|
|
// Just make sure this has 3 arguments per LLVM spec.
|
|
return F->arg_size() == 4;
|
|
}
|
|
|
|
/// Because of alignment and instruction information that we don't have, we
|
|
/// leave the bulk of this to the code generators. The optimization here just
|
|
/// deals with a few degenerate cases where the length parameter is constant
|
|
/// and the alignment matches the sizes of our intrinsic types so we can do
|
|
/// store instead of the memcpy call. Other calls are transformed into the
|
|
/// llvm.memset intrinsic.
|
|
/// @brief Perform the memset optimization.
|
|
virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &TD) {
|
|
// Make sure we have constant int values to work with
|
|
ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
|
|
if (!LEN)
|
|
return false;
|
|
ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
|
|
if (!ALIGN)
|
|
return false;
|
|
|
|
// Extract the length and alignment
|
|
uint64_t len = LEN->getZExtValue();
|
|
uint64_t alignment = ALIGN->getZExtValue();
|
|
|
|
// Alignment 0 is identity for alignment 1
|
|
if (alignment == 0)
|
|
alignment = 1;
|
|
|
|
// If the length is zero, this is a no-op
|
|
if (len == 0) {
|
|
// memset(d,c,0,a) -> noop
|
|
return ReplaceCallWith(ci, 0);
|
|
}
|
|
|
|
// If the length is larger than the alignment, we can't optimize
|
|
if (len > alignment)
|
|
return false;
|
|
|
|
// Make sure we have a constant ubyte to work with so we can extract
|
|
// the value to be filled.
|
|
ConstantInt* FILL = dyn_cast<ConstantInt>(ci->getOperand(2));
|
|
if (!FILL)
|
|
return false;
|
|
if (FILL->getType() != Type::Int8Ty)
|
|
return false;
|
|
|
|
// memset(s,c,n) -> store s, c (for n=1,2,4,8)
|
|
|
|
// Extract the fill character
|
|
uint64_t fill_char = FILL->getZExtValue();
|
|
uint64_t fill_value = fill_char;
|
|
|
|
// Get the type we will cast to, based on size of memory area to fill, and
|
|
// and the value we will store there.
|
|
Value* dest = ci->getOperand(1);
|
|
const Type* castType = 0;
|
|
switch (len) {
|
|
case 1:
|
|
castType = Type::Int8Ty;
|
|
break;
|
|
case 2:
|
|
castType = Type::Int16Ty;
|
|
fill_value |= fill_char << 8;
|
|
break;
|
|
case 4:
|
|
castType = Type::Int32Ty;
|
|
fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
|
|
break;
|
|
case 8:
|
|
castType = Type::Int64Ty;
|
|
fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
|
|
fill_value |= fill_char << 32 | fill_char << 40 | fill_char << 48;
|
|
fill_value |= fill_char << 56;
|
|
break;
|
|
default:
|
|
return false;
|
|
}
|
|
|
|
// Cast dest to the right sized primitive and then load/store
|
|
CastInst* DestCast = new BitCastInst(dest, PointerType::get(castType),
|
|
dest->getName()+".cast", ci);
|
|
new StoreInst(ConstantInt::get(castType,fill_value),DestCast, ci);
|
|
return ReplaceCallWith(ci, 0);
|
|
}
|
|
};
|
|
|
|
LLVMMemSetOptimization MemSet32Optimizer("llvm.memset.i32");
|
|
LLVMMemSetOptimization MemSet64Optimizer("llvm.memset.i64");
|
|
|
|
|
|
/// This LibCallOptimization will simplify calls to the "pow" library
|
|
/// function. It looks for cases where the result of pow is well known and
|
|
/// substitutes the appropriate value.
|
|
/// @brief Simplify the pow library function.
|
|
struct VISIBILITY_HIDDEN PowOptimization : public LibCallOptimization {
|
|
public:
|
|
/// @brief Default Constructor
|
|
PowOptimization() : LibCallOptimization("pow",
|
|
"Number of 'pow' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "pow" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
|
|
// Just make sure this has 2 arguments
|
|
return (f->arg_size() == 2);
|
|
}
|
|
|
|
/// @brief Perform the pow optimization.
|
|
virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
|
|
const Type *Ty = cast<Function>(ci->getOperand(0))->getReturnType();
|
|
Value* base = ci->getOperand(1);
|
|
Value* expn = ci->getOperand(2);
|
|
if (ConstantFP *Op1 = dyn_cast<ConstantFP>(base)) {
|
|
double Op1V = Op1->getValue();
|
|
if (Op1V == 1.0) // pow(1.0,x) -> 1.0
|
|
return ReplaceCallWith(ci, ConstantFP::get(Ty, 1.0));
|
|
} else if (ConstantFP* Op2 = dyn_cast<ConstantFP>(expn)) {
|
|
double Op2V = Op2->getValue();
|
|
if (Op2V == 0.0) {
|
|
// pow(x,0.0) -> 1.0
|
|
return ReplaceCallWith(ci, ConstantFP::get(Ty,1.0));
|
|
} else if (Op2V == 0.5) {
|
|
// pow(x,0.5) -> sqrt(x)
|
|
CallInst* sqrt_inst = new CallInst(SLC.get_sqrt(), base,
|
|
ci->getName()+".pow",ci);
|
|
return ReplaceCallWith(ci, sqrt_inst);
|
|
} else if (Op2V == 1.0) {
|
|
// pow(x,1.0) -> x
|
|
return ReplaceCallWith(ci, base);
|
|
} else if (Op2V == -1.0) {
|
|
// pow(x,-1.0) -> 1.0/x
|
|
Value *div_inst =
|
|
BinaryOperator::createFDiv(ConstantFP::get(Ty, 1.0), base,
|
|
ci->getName()+".pow", ci);
|
|
return ReplaceCallWith(ci, div_inst);
|
|
}
|
|
}
|
|
return false; // opt failed
|
|
}
|
|
} PowOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "printf" library
|
|
/// function. It looks for cases where the result of printf is not used and the
|
|
/// operation can be reduced to something simpler.
|
|
/// @brief Simplify the printf library function.
|
|
struct VISIBILITY_HIDDEN PrintfOptimization : public LibCallOptimization {
|
|
public:
|
|
/// @brief Default Constructor
|
|
PrintfOptimization() : LibCallOptimization("printf",
|
|
"Number of 'printf' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "printf" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
|
|
// Just make sure this has at least 1 arguments
|
|
return F->arg_size() >= 1;
|
|
}
|
|
|
|
/// @brief Perform the printf optimization.
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
// If the call has more than 2 operands, we can't optimize it
|
|
if (CI->getNumOperands() != 3)
|
|
return false;
|
|
|
|
// All the optimizations depend on the length of the first argument and the
|
|
// fact that it is a constant string array. Check that now
|
|
std::string FormatStr;
|
|
if (!GetConstantStringInfo(CI->getOperand(1), FormatStr))
|
|
return false;
|
|
|
|
// Only support %c or "%s\n" for now.
|
|
if (FormatStr.size() < 2 || FormatStr[0] != '%')
|
|
return false;
|
|
|
|
// Get the second character and switch on its value
|
|
switch (FormatStr[1]) {
|
|
default: return false;
|
|
case 's':
|
|
if (FormatStr != "%s\n" ||
|
|
// TODO: could insert strlen call to compute string length.
|
|
!CI->use_empty())
|
|
return false;
|
|
|
|
// printf("%s\n",str) -> puts(str)
|
|
new CallInst(SLC.get_puts(), CastToCStr(CI->getOperand(2), CI),
|
|
CI->getName(), CI);
|
|
return ReplaceCallWith(CI, 0);
|
|
case 'c': {
|
|
// printf("%c",c) -> putchar(c)
|
|
if (FormatStr.size() != 2)
|
|
return false;
|
|
|
|
Value *V = CI->getOperand(2);
|
|
if (!isa<IntegerType>(V->getType()) ||
|
|
cast<IntegerType>(V->getType())->getBitWidth() > 32)
|
|
return false;
|
|
|
|
V = CastInst::createZExtOrBitCast(V, Type::Int32Ty, CI->getName()+".int",
|
|
CI);
|
|
new CallInst(SLC.get_putchar(), V, "", CI);
|
|
return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
|
|
}
|
|
}
|
|
}
|
|
} PrintfOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "fprintf" library
|
|
/// function. It looks for cases where the result of fprintf is not used and the
|
|
/// operation can be reduced to something simpler.
|
|
/// @brief Simplify the fprintf library function.
|
|
struct VISIBILITY_HIDDEN FPrintFOptimization : public LibCallOptimization {
|
|
public:
|
|
/// @brief Default Constructor
|
|
FPrintFOptimization() : LibCallOptimization("fprintf",
|
|
"Number of 'fprintf' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "fprintf" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
|
|
const FunctionType *FT = F->getFunctionType();
|
|
return FT->getNumParams() == 2 && // two fixed arguments.
|
|
FT->getParamType(1) == PointerType::get(Type::Int8Ty) &&
|
|
isa<PointerType>(FT->getParamType(0)) &&
|
|
isa<IntegerType>(FT->getReturnType());
|
|
}
|
|
|
|
/// @brief Perform the fprintf optimization.
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
// If the call has more than 3 operands, we can't optimize it
|
|
if (CI->getNumOperands() != 3 && CI->getNumOperands() != 4)
|
|
return false;
|
|
|
|
// All the optimizations depend on the format string.
|
|
std::string FormatStr;
|
|
if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
|
|
return false;
|
|
|
|
// If this is just a format string, turn it into fwrite.
|
|
if (CI->getNumOperands() == 3) {
|
|
for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
|
|
if (FormatStr[i] == '%')
|
|
return false; // we found a format specifier
|
|
|
|
// fprintf(file,fmt) -> fwrite(fmt,strlen(fmt),file)
|
|
const Type *FILEty = CI->getOperand(1)->getType();
|
|
|
|
Value *FWriteArgs[] = {
|
|
CI->getOperand(2),
|
|
ConstantInt::get(SLC.getIntPtrType(), FormatStr.size()),
|
|
ConstantInt::get(SLC.getIntPtrType(), 1),
|
|
CI->getOperand(1)
|
|
};
|
|
new CallInst(SLC.get_fwrite(FILEty), FWriteArgs, 4, CI->getName(), CI);
|
|
return ReplaceCallWith(CI, ConstantInt::get(CI->getType(),
|
|
FormatStr.size()));
|
|
}
|
|
|
|
// The remaining optimizations require the format string to be length 2:
|
|
// "%s" or "%c".
|
|
if (FormatStr.size() != 2 || FormatStr[0] != '%')
|
|
return false;
|
|
|
|
// Get the second character and switch on its value
|
|
switch (FormatStr[1]) {
|
|
case 'c': {
|
|
// fprintf(file,"%c",c) -> fputc(c,file)
|
|
const Type *FILETy = CI->getOperand(1)->getType();
|
|
Value *C = CastInst::createZExtOrBitCast(CI->getOperand(3), Type::Int32Ty,
|
|
CI->getName()+".int", CI);
|
|
new CallInst(SLC.get_fputc(FILETy), C, CI->getOperand(1), "", CI);
|
|
return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
|
|
}
|
|
case 's': {
|
|
const Type *FILETy = CI->getOperand(1)->getType();
|
|
|
|
// If the result of the fprintf call is used, we can't do this.
|
|
// TODO: we should insert a strlen call.
|
|
if (!CI->use_empty())
|
|
return false;
|
|
|
|
// fprintf(file,"%s",str) -> fputs(str,file)
|
|
new CallInst(SLC.get_fputs(FILETy), CastToCStr(CI->getOperand(3), CI),
|
|
CI->getOperand(1), CI->getName(), CI);
|
|
return ReplaceCallWith(CI, 0);
|
|
}
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
} FPrintFOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "sprintf" library
|
|
/// function. It looks for cases where the result of sprintf is not used and the
|
|
/// operation can be reduced to something simpler.
|
|
/// @brief Simplify the sprintf library function.
|
|
struct VISIBILITY_HIDDEN SPrintFOptimization : public LibCallOptimization {
|
|
public:
|
|
/// @brief Default Constructor
|
|
SPrintFOptimization() : LibCallOptimization("sprintf",
|
|
"Number of 'sprintf' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "sprintf" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
|
|
const FunctionType *FT = F->getFunctionType();
|
|
return FT->getNumParams() == 2 && // two fixed arguments.
|
|
FT->getParamType(1) == PointerType::get(Type::Int8Ty) &&
|
|
FT->getParamType(0) == FT->getParamType(1) &&
|
|
isa<IntegerType>(FT->getReturnType());
|
|
}
|
|
|
|
/// @brief Perform the sprintf optimization.
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
// If the call has more than 3 operands, we can't optimize it
|
|
if (CI->getNumOperands() != 3 && CI->getNumOperands() != 4)
|
|
return false;
|
|
|
|
std::string FormatStr;
|
|
if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
|
|
return false;
|
|
|
|
if (CI->getNumOperands() == 3) {
|
|
// Make sure there's no % in the constant array
|
|
for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
|
|
if (FormatStr[i] == '%')
|
|
return false; // we found a format specifier
|
|
|
|
// sprintf(str,fmt) -> llvm.memcpy(str,fmt,strlen(fmt),1)
|
|
Value *MemCpyArgs[] = {
|
|
CI->getOperand(1), CI->getOperand(2),
|
|
ConstantInt::get(SLC.getIntPtrType(),
|
|
FormatStr.size()+1), // Copy the nul byte.
|
|
ConstantInt::get(Type::Int32Ty, 1)
|
|
};
|
|
new CallInst(SLC.get_memcpy(), MemCpyArgs, 4, "", CI);
|
|
return ReplaceCallWith(CI, ConstantInt::get(CI->getType(),
|
|
FormatStr.size()));
|
|
}
|
|
|
|
// The remaining optimizations require the format string to be "%s" or "%c".
|
|
if (FormatStr.size() != 2 || FormatStr[0] != '%')
|
|
return false;
|
|
|
|
// Get the second character and switch on its value
|
|
switch (FormatStr[1]) {
|
|
case 'c': {
|
|
// sprintf(dest,"%c",chr) -> store chr, dest
|
|
Value *V = CastInst::createTruncOrBitCast(CI->getOperand(3),
|
|
Type::Int8Ty, "char", CI);
|
|
new StoreInst(V, CI->getOperand(1), CI);
|
|
Value *Ptr = new GetElementPtrInst(CI->getOperand(1),
|
|
ConstantInt::get(Type::Int32Ty, 1),
|
|
CI->getOperand(1)->getName()+".end",
|
|
CI);
|
|
new StoreInst(ConstantInt::get(Type::Int8Ty,0), Ptr, CI);
|
|
return ReplaceCallWith(CI, ConstantInt::get(Type::Int32Ty, 1));
|
|
}
|
|
case 's': {
|
|
// sprintf(dest,"%s",str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
|
|
Value *Len = new CallInst(SLC.get_strlen(),
|
|
CastToCStr(CI->getOperand(3), CI),
|
|
CI->getOperand(3)->getName()+".len", CI);
|
|
Value *UnincLen = Len;
|
|
Len = BinaryOperator::createAdd(Len, ConstantInt::get(Len->getType(), 1),
|
|
Len->getName()+"1", CI);
|
|
Value *MemcpyArgs[4] = {
|
|
CI->getOperand(1),
|
|
CastToCStr(CI->getOperand(3), CI),
|
|
Len,
|
|
ConstantInt::get(Type::Int32Ty, 1)
|
|
};
|
|
new CallInst(SLC.get_memcpy(), MemcpyArgs, 4, "", CI);
|
|
|
|
// The strlen result is the unincremented number of bytes in the string.
|
|
if (!CI->use_empty()) {
|
|
if (UnincLen->getType() != CI->getType())
|
|
UnincLen = CastInst::createIntegerCast(UnincLen, CI->getType(), false,
|
|
Len->getName(), CI);
|
|
CI->replaceAllUsesWith(UnincLen);
|
|
}
|
|
return ReplaceCallWith(CI, 0);
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
} SPrintFOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "fputs" library
|
|
/// function. It looks for cases where the result of fputs is not used and the
|
|
/// operation can be reduced to something simpler.
|
|
/// @brief Simplify the fputs library function.
|
|
struct VISIBILITY_HIDDEN FPutsOptimization : public LibCallOptimization {
|
|
public:
|
|
/// @brief Default Constructor
|
|
FPutsOptimization() : LibCallOptimization("fputs",
|
|
"Number of 'fputs' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "fputs" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
|
|
// Just make sure this has 2 arguments
|
|
return F->arg_size() == 2;
|
|
}
|
|
|
|
/// @brief Perform the fputs optimization.
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
// If the result is used, none of these optimizations work.
|
|
if (!CI->use_empty())
|
|
return false;
|
|
|
|
// All the optimizations depend on the length of the first argument and the
|
|
// fact that it is a constant string array. Check that now
|
|
std::string Str;
|
|
if (!GetConstantStringInfo(CI->getOperand(1), Str))
|
|
return false;
|
|
|
|
const Type *FILETy = CI->getOperand(2)->getType();
|
|
// fputs(s,F) -> fwrite(s,1,len,F) (if s is constant and strlen(s) > 1)
|
|
Value *FWriteParms[4] = {
|
|
CI->getOperand(1),
|
|
ConstantInt::get(SLC.getIntPtrType(), Str.size()),
|
|
ConstantInt::get(SLC.getIntPtrType(), 1),
|
|
CI->getOperand(2)
|
|
};
|
|
new CallInst(SLC.get_fwrite(FILETy), FWriteParms, 4, "", CI);
|
|
return ReplaceCallWith(CI, 0); // Known to have no uses (see above).
|
|
}
|
|
} FPutsOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "fwrite" function.
|
|
struct VISIBILITY_HIDDEN FWriteOptimization : public LibCallOptimization {
|
|
public:
|
|
/// @brief Default Constructor
|
|
FWriteOptimization() : LibCallOptimization("fwrite",
|
|
"Number of 'fwrite' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "fputs" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
|
|
const FunctionType *FT = F->getFunctionType();
|
|
return FT->getNumParams() == 4 &&
|
|
FT->getParamType(0) == PointerType::get(Type::Int8Ty) &&
|
|
FT->getParamType(1) == FT->getParamType(2) &&
|
|
isa<IntegerType>(FT->getParamType(1)) &&
|
|
isa<PointerType>(FT->getParamType(3)) &&
|
|
isa<IntegerType>(FT->getReturnType());
|
|
}
|
|
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
// Get the element size and count.
|
|
uint64_t EltSize, EltCount;
|
|
if (ConstantInt *C = dyn_cast<ConstantInt>(CI->getOperand(2)))
|
|
EltSize = C->getZExtValue();
|
|
else
|
|
return false;
|
|
if (ConstantInt *C = dyn_cast<ConstantInt>(CI->getOperand(3)))
|
|
EltCount = C->getZExtValue();
|
|
else
|
|
return false;
|
|
|
|
// If this is writing zero records, remove the call (it's a noop).
|
|
if (EltSize * EltCount == 0)
|
|
return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
|
|
|
|
// If this is writing one byte, turn it into fputc.
|
|
if (EltSize == 1 && EltCount == 1) {
|
|
// fwrite(s,1,1,F) -> fputc(s[0],F)
|
|
Value *Ptr = CI->getOperand(1);
|
|
Value *Val = new LoadInst(Ptr, Ptr->getName()+".byte", CI);
|
|
Val = new ZExtInst(Val, Type::Int32Ty, Val->getName()+".int", CI);
|
|
const Type *FILETy = CI->getOperand(4)->getType();
|
|
new CallInst(SLC.get_fputc(FILETy), Val, CI->getOperand(4), "", CI);
|
|
return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
|
|
}
|
|
return false;
|
|
}
|
|
} FWriteOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "isdigit" library
|
|
/// function. It simply does range checks the parameter explicitly.
|
|
/// @brief Simplify the isdigit library function.
|
|
struct VISIBILITY_HIDDEN isdigitOptimization : public LibCallOptimization {
|
|
public:
|
|
isdigitOptimization() : LibCallOptimization("isdigit",
|
|
"Number of 'isdigit' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "isdigit" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
|
|
// Just make sure this has 1 argument
|
|
return (f->arg_size() == 1);
|
|
}
|
|
|
|
/// @brief Perform the toascii optimization.
|
|
virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
|
|
if (ConstantInt* CI = dyn_cast<ConstantInt>(ci->getOperand(1))) {
|
|
// isdigit(c) -> 0 or 1, if 'c' is constant
|
|
uint64_t val = CI->getZExtValue();
|
|
if (val >= '0' && val <= '9')
|
|
return ReplaceCallWith(ci, ConstantInt::get(Type::Int32Ty, 1));
|
|
else
|
|
return ReplaceCallWith(ci, ConstantInt::get(Type::Int32Ty, 0));
|
|
}
|
|
|
|
// isdigit(c) -> (unsigned)c - '0' <= 9
|
|
CastInst* cast = CastInst::createIntegerCast(ci->getOperand(1),
|
|
Type::Int32Ty, false/*ZExt*/, ci->getOperand(1)->getName()+".uint", ci);
|
|
BinaryOperator* sub_inst = BinaryOperator::createSub(cast,
|
|
ConstantInt::get(Type::Int32Ty,0x30),
|
|
ci->getOperand(1)->getName()+".sub",ci);
|
|
ICmpInst* setcond_inst = new ICmpInst(ICmpInst::ICMP_ULE,sub_inst,
|
|
ConstantInt::get(Type::Int32Ty,9),
|
|
ci->getOperand(1)->getName()+".cmp",ci);
|
|
CastInst* c2 = new ZExtInst(setcond_inst, Type::Int32Ty,
|
|
ci->getOperand(1)->getName()+".isdigit", ci);
|
|
return ReplaceCallWith(ci, c2);
|
|
}
|
|
} isdigitOptimizer;
|
|
|
|
struct VISIBILITY_HIDDEN isasciiOptimization : public LibCallOptimization {
|
|
public:
|
|
isasciiOptimization()
|
|
: LibCallOptimization("isascii", "Number of 'isascii' calls simplified") {}
|
|
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
|
|
return F->arg_size() == 1 && F->arg_begin()->getType()->isInteger() &&
|
|
F->getReturnType()->isInteger();
|
|
}
|
|
|
|
/// @brief Perform the isascii optimization.
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
// isascii(c) -> (unsigned)c < 128
|
|
Value *V = CI->getOperand(1);
|
|
Value *Cmp = new ICmpInst(ICmpInst::ICMP_ULT, V,
|
|
ConstantInt::get(V->getType(), 128),
|
|
V->getName()+".isascii", CI);
|
|
if (Cmp->getType() != CI->getType())
|
|
Cmp = new BitCastInst(Cmp, CI->getType(), Cmp->getName(), CI);
|
|
return ReplaceCallWith(CI, Cmp);
|
|
}
|
|
} isasciiOptimizer;
|
|
|
|
|
|
/// This LibCallOptimization will simplify calls to the "toascii" library
|
|
/// function. It simply does the corresponding and operation to restrict the
|
|
/// range of values to the ASCII character set (0-127).
|
|
/// @brief Simplify the toascii library function.
|
|
struct VISIBILITY_HIDDEN ToAsciiOptimization : public LibCallOptimization {
|
|
public:
|
|
/// @brief Default Constructor
|
|
ToAsciiOptimization() : LibCallOptimization("toascii",
|
|
"Number of 'toascii' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "fputs" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
|
|
// Just make sure this has 2 arguments
|
|
return (f->arg_size() == 1);
|
|
}
|
|
|
|
/// @brief Perform the toascii optimization.
|
|
virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
|
|
// toascii(c) -> (c & 0x7f)
|
|
Value *chr = ci->getOperand(1);
|
|
Value *and_inst = BinaryOperator::createAnd(chr,
|
|
ConstantInt::get(chr->getType(),0x7F),ci->getName()+".toascii",ci);
|
|
return ReplaceCallWith(ci, and_inst);
|
|
}
|
|
} ToAsciiOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "ffs" library
|
|
/// calls which find the first set bit in an int, long, or long long. The
|
|
/// optimization is to compute the result at compile time if the argument is
|
|
/// a constant.
|
|
/// @brief Simplify the ffs library function.
|
|
struct VISIBILITY_HIDDEN FFSOptimization : public LibCallOptimization {
|
|
protected:
|
|
/// @brief Subclass Constructor
|
|
FFSOptimization(const char* funcName, const char* description)
|
|
: LibCallOptimization(funcName, description) {}
|
|
|
|
public:
|
|
/// @brief Default Constructor
|
|
FFSOptimization() : LibCallOptimization("ffs",
|
|
"Number of 'ffs' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "ffs" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
|
|
// Just make sure this has 2 arguments
|
|
return F->arg_size() == 1 && F->getReturnType() == Type::Int32Ty;
|
|
}
|
|
|
|
/// @brief Perform the ffs optimization.
|
|
virtual bool OptimizeCall(CallInst *TheCall, SimplifyLibCalls &SLC) {
|
|
if (ConstantInt *CI = dyn_cast<ConstantInt>(TheCall->getOperand(1))) {
|
|
// ffs(cnst) -> bit#
|
|
// ffsl(cnst) -> bit#
|
|
// ffsll(cnst) -> bit#
|
|
uint64_t val = CI->getZExtValue();
|
|
int result = 0;
|
|
if (val) {
|
|
++result;
|
|
while ((val & 1) == 0) {
|
|
++result;
|
|
val >>= 1;
|
|
}
|
|
}
|
|
return ReplaceCallWith(TheCall, ConstantInt::get(Type::Int32Ty, result));
|
|
}
|
|
|
|
// ffs(x) -> x == 0 ? 0 : llvm.cttz(x)+1
|
|
// ffsl(x) -> x == 0 ? 0 : llvm.cttz(x)+1
|
|
// ffsll(x) -> x == 0 ? 0 : llvm.cttz(x)+1
|
|
const Type *ArgType = TheCall->getOperand(1)->getType();
|
|
const char *CTTZName;
|
|
assert(ArgType->getTypeID() == Type::IntegerTyID &&
|
|
"llvm.cttz argument is not an integer?");
|
|
unsigned BitWidth = cast<IntegerType>(ArgType)->getBitWidth();
|
|
if (BitWidth == 8)
|
|
CTTZName = "llvm.cttz.i8";
|
|
else if (BitWidth == 16)
|
|
CTTZName = "llvm.cttz.i16";
|
|
else if (BitWidth == 32)
|
|
CTTZName = "llvm.cttz.i32";
|
|
else {
|
|
assert(BitWidth == 64 && "Unknown bitwidth");
|
|
CTTZName = "llvm.cttz.i64";
|
|
}
|
|
|
|
Constant *F = SLC.getModule()->getOrInsertFunction(CTTZName, ArgType,
|
|
ArgType, NULL);
|
|
Value *V = CastInst::createIntegerCast(TheCall->getOperand(1), ArgType,
|
|
false/*ZExt*/, "tmp", TheCall);
|
|
Value *V2 = new CallInst(F, V, "tmp", TheCall);
|
|
V2 = CastInst::createIntegerCast(V2, Type::Int32Ty, false/*ZExt*/,
|
|
"tmp", TheCall);
|
|
V2 = BinaryOperator::createAdd(V2, ConstantInt::get(Type::Int32Ty, 1),
|
|
"tmp", TheCall);
|
|
Value *Cond = new ICmpInst(ICmpInst::ICMP_EQ, V,
|
|
Constant::getNullValue(V->getType()), "tmp",
|
|
TheCall);
|
|
V2 = new SelectInst(Cond, ConstantInt::get(Type::Int32Ty, 0), V2,
|
|
TheCall->getName(), TheCall);
|
|
return ReplaceCallWith(TheCall, V2);
|
|
}
|
|
} FFSOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "ffsl" library
|
|
/// calls. It simply uses FFSOptimization for which the transformation is
|
|
/// identical.
|
|
/// @brief Simplify the ffsl library function.
|
|
struct VISIBILITY_HIDDEN FFSLOptimization : public FFSOptimization {
|
|
public:
|
|
/// @brief Default Constructor
|
|
FFSLOptimization() : FFSOptimization("ffsl",
|
|
"Number of 'ffsl' calls simplified") {}
|
|
|
|
} FFSLOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "ffsll" library
|
|
/// calls. It simply uses FFSOptimization for which the transformation is
|
|
/// identical.
|
|
/// @brief Simplify the ffsl library function.
|
|
struct VISIBILITY_HIDDEN FFSLLOptimization : public FFSOptimization {
|
|
public:
|
|
/// @brief Default Constructor
|
|
FFSLLOptimization() : FFSOptimization("ffsll",
|
|
"Number of 'ffsll' calls simplified") {}
|
|
|
|
} FFSLLOptimizer;
|
|
|
|
/// This optimizes unary functions that take and return doubles.
|
|
struct UnaryDoubleFPOptimizer : public LibCallOptimization {
|
|
UnaryDoubleFPOptimizer(const char *Fn, const char *Desc)
|
|
: LibCallOptimization(Fn, Desc) {}
|
|
|
|
// Make sure that this function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
|
|
return F->arg_size() == 1 && F->arg_begin()->getType() == Type::DoubleTy &&
|
|
F->getReturnType() == Type::DoubleTy;
|
|
}
|
|
|
|
/// ShrinkFunctionToFloatVersion - If the input to this function is really a
|
|
/// float, strength reduce this to a float version of the function,
|
|
/// e.g. floor((double)FLT) -> (double)floorf(FLT). This can only be called
|
|
/// when the target supports the destination function and where there can be
|
|
/// no precision loss.
|
|
static bool ShrinkFunctionToFloatVersion(CallInst *CI, SimplifyLibCalls &SLC,
|
|
Constant *(SimplifyLibCalls::*FP)()){
|
|
if (FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getOperand(1)))
|
|
if (Cast->getOperand(0)->getType() == Type::FloatTy) {
|
|
Value *New = new CallInst((SLC.*FP)(), Cast->getOperand(0),
|
|
CI->getName(), CI);
|
|
New = new FPExtInst(New, Type::DoubleTy, CI->getName(), CI);
|
|
CI->replaceAllUsesWith(New);
|
|
CI->eraseFromParent();
|
|
if (Cast->use_empty())
|
|
Cast->eraseFromParent();
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
};
|
|
|
|
|
|
struct VISIBILITY_HIDDEN FloorOptimization : public UnaryDoubleFPOptimizer {
|
|
FloorOptimization()
|
|
: UnaryDoubleFPOptimizer("floor", "Number of 'floor' calls simplified") {}
|
|
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
#ifdef HAVE_FLOORF
|
|
// If this is a float argument passed in, convert to floorf.
|
|
if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_floorf))
|
|
return true;
|
|
#endif
|
|
return false; // opt failed
|
|
}
|
|
} FloorOptimizer;
|
|
|
|
struct VISIBILITY_HIDDEN CeilOptimization : public UnaryDoubleFPOptimizer {
|
|
CeilOptimization()
|
|
: UnaryDoubleFPOptimizer("ceil", "Number of 'ceil' calls simplified") {}
|
|
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
#ifdef HAVE_CEILF
|
|
// If this is a float argument passed in, convert to ceilf.
|
|
if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_ceilf))
|
|
return true;
|
|
#endif
|
|
return false; // opt failed
|
|
}
|
|
} CeilOptimizer;
|
|
|
|
struct VISIBILITY_HIDDEN RoundOptimization : public UnaryDoubleFPOptimizer {
|
|
RoundOptimization()
|
|
: UnaryDoubleFPOptimizer("round", "Number of 'round' calls simplified") {}
|
|
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
#ifdef HAVE_ROUNDF
|
|
// If this is a float argument passed in, convert to roundf.
|
|
if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_roundf))
|
|
return true;
|
|
#endif
|
|
return false; // opt failed
|
|
}
|
|
} RoundOptimizer;
|
|
|
|
struct VISIBILITY_HIDDEN RintOptimization : public UnaryDoubleFPOptimizer {
|
|
RintOptimization()
|
|
: UnaryDoubleFPOptimizer("rint", "Number of 'rint' calls simplified") {}
|
|
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
#ifdef HAVE_RINTF
|
|
// If this is a float argument passed in, convert to rintf.
|
|
if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_rintf))
|
|
return true;
|
|
#endif
|
|
return false; // opt failed
|
|
}
|
|
} RintOptimizer;
|
|
|
|
struct VISIBILITY_HIDDEN NearByIntOptimization : public UnaryDoubleFPOptimizer {
|
|
NearByIntOptimization()
|
|
: UnaryDoubleFPOptimizer("nearbyint",
|
|
"Number of 'nearbyint' calls simplified") {}
|
|
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
#ifdef HAVE_NEARBYINTF
|
|
// If this is a float argument passed in, convert to nearbyintf.
|
|
if (ShrinkFunctionToFloatVersion(CI, SLC,&SimplifyLibCalls::get_nearbyintf))
|
|
return true;
|
|
#endif
|
|
return false; // opt failed
|
|
}
|
|
} NearByIntOptimizer;
|
|
|
|
/// GetConstantStringInfo - This function computes the length of a
|
|
/// null-terminated constant array of integers. This function can't rely on the
|
|
/// size of the constant array because there could be a null terminator in the
|
|
/// middle of the array.
|
|
///
|
|
/// We also have to bail out if we find a non-integer constant initializer
|
|
/// of one of the elements or if there is no null-terminator. The logic
|
|
/// below checks each of these conditions and will return true only if all
|
|
/// conditions are met. If the conditions aren't met, this returns false.
|
|
///
|
|
/// If successful, the \p Array param is set to the constant array being
|
|
/// indexed, the \p Length parameter is set to the length of the null-terminated
|
|
/// string pointed to by V, the \p StartIdx value is set to the first
|
|
/// element of the Array that V points to, and true is returned.
|
|
static bool GetConstantStringInfo(Value *V, std::string &Str) {
|
|
// Look through noop bitcast instructions.
|
|
if (BitCastInst *BCI = dyn_cast<BitCastInst>(V)) {
|
|
if (BCI->getType() == BCI->getOperand(0)->getType())
|
|
return GetConstantStringInfo(BCI->getOperand(0), Str);
|
|
return false;
|
|
}
|
|
|
|
// If the value is not a GEP instruction nor a constant expression with a
|
|
// GEP instruction, then return false because ConstantArray can't occur
|
|
// any other way
|
|
User *GEP = 0;
|
|
if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
|
|
GEP = GEPI;
|
|
} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
|
|
if (CE->getOpcode() != Instruction::GetElementPtr)
|
|
return false;
|
|
GEP = CE;
|
|
} else {
|
|
return false;
|
|
}
|
|
|
|
// Make sure the GEP has exactly three arguments.
|
|
if (GEP->getNumOperands() != 3)
|
|
return false;
|
|
|
|
// Check to make sure that the first operand of the GEP is an integer and
|
|
// has value 0 so that we are sure we're indexing into the initializer.
|
|
if (ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(1))) {
|
|
if (!Idx->isZero())
|
|
return false;
|
|
} else
|
|
return false;
|
|
|
|
// If the second index isn't a ConstantInt, then this is a variable index
|
|
// into the array. If this occurs, we can't say anything meaningful about
|
|
// the string.
|
|
uint64_t StartIdx = 0;
|
|
if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
|
|
StartIdx = CI->getZExtValue();
|
|
else
|
|
return false;
|
|
|
|
// The GEP instruction, constant or instruction, must reference a global
|
|
// variable that is a constant and is initialized. The referenced constant
|
|
// initializer is the array that we'll use for optimization.
|
|
GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
|
|
if (!GV || !GV->isConstant() || !GV->hasInitializer())
|
|
return false;
|
|
Constant *GlobalInit = GV->getInitializer();
|
|
|
|
// Handle the ConstantAggregateZero case
|
|
if (isa<ConstantAggregateZero>(GlobalInit)) {
|
|
// This is a degenerate case. The initializer is constant zero so the
|
|
// length of the string must be zero.
|
|
Str.clear();
|
|
return true;
|
|
}
|
|
|
|
// Must be a Constant Array
|
|
ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
|
|
if (!Array) return false;
|
|
|
|
// Get the number of elements in the array
|
|
uint64_t NumElts = Array->getType()->getNumElements();
|
|
|
|
// Traverse the constant array from StartIdx (derived above) which is
|
|
// the place the GEP refers to in the array.
|
|
for (unsigned i = StartIdx; i < NumElts; ++i) {
|
|
Constant *Elt = Array->getOperand(i);
|
|
ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
|
|
if (!CI) // This array isn't suitable, non-int initializer.
|
|
return false;
|
|
if (CI->isZero())
|
|
return true; // we found end of string, success!
|
|
Str += (char)CI->getZExtValue();
|
|
}
|
|
|
|
return false; // The array isn't null terminated.
|
|
}
|
|
|
|
/// CastToCStr - Return V if it is an sbyte*, otherwise cast it to sbyte*,
|
|
/// inserting the cast before IP, and return the cast.
|
|
/// @brief Cast a value to a "C" string.
|
|
static Value *CastToCStr(Value *V, Instruction *IP) {
|
|
assert(isa<PointerType>(V->getType()) &&
|
|
"Can't cast non-pointer type to C string type");
|
|
const Type *SBPTy = PointerType::get(Type::Int8Ty);
|
|
if (V->getType() != SBPTy)
|
|
return new BitCastInst(V, SBPTy, V->getName(), IP);
|
|
return V;
|
|
}
|
|
|
|
// TODO:
|
|
// Additional cases that we need to add to this file:
|
|
//
|
|
// cbrt:
|
|
// * cbrt(expN(X)) -> expN(x/3)
|
|
// * cbrt(sqrt(x)) -> pow(x,1/6)
|
|
// * cbrt(sqrt(x)) -> pow(x,1/9)
|
|
//
|
|
// cos, cosf, cosl:
|
|
// * cos(-x) -> cos(x)
|
|
//
|
|
// exp, expf, expl:
|
|
// * exp(log(x)) -> x
|
|
//
|
|
// log, logf, logl:
|
|
// * log(exp(x)) -> x
|
|
// * log(x**y) -> y*log(x)
|
|
// * log(exp(y)) -> y*log(e)
|
|
// * log(exp2(y)) -> y*log(2)
|
|
// * log(exp10(y)) -> y*log(10)
|
|
// * log(sqrt(x)) -> 0.5*log(x)
|
|
// * log(pow(x,y)) -> y*log(x)
|
|
//
|
|
// lround, lroundf, lroundl:
|
|
// * lround(cnst) -> cnst'
|
|
//
|
|
// memcmp:
|
|
// * memcmp(x,y,l) -> cnst
|
|
// (if all arguments are constant and strlen(x) <= l and strlen(y) <= l)
|
|
//
|
|
// memmove:
|
|
// * memmove(d,s,l,a) -> memcpy(d,s,l,a)
|
|
// (if s is a global constant array)
|
|
//
|
|
// pow, powf, powl:
|
|
// * pow(exp(x),y) -> exp(x*y)
|
|
// * pow(sqrt(x),y) -> pow(x,y*0.5)
|
|
// * pow(pow(x,y),z)-> pow(x,y*z)
|
|
//
|
|
// puts:
|
|
// * puts("") -> fputc("\n",stdout) (how do we get "stdout"?)
|
|
//
|
|
// round, roundf, roundl:
|
|
// * round(cnst) -> cnst'
|
|
//
|
|
// signbit:
|
|
// * signbit(cnst) -> cnst'
|
|
// * signbit(nncst) -> 0 (if pstv is a non-negative constant)
|
|
//
|
|
// sqrt, sqrtf, sqrtl:
|
|
// * sqrt(expN(x)) -> expN(x*0.5)
|
|
// * sqrt(Nroot(x)) -> pow(x,1/(2*N))
|
|
// * sqrt(pow(x,y)) -> pow(|x|,y*0.5)
|
|
//
|
|
// stpcpy:
|
|
// * stpcpy(str, "literal") ->
|
|
// llvm.memcpy(str,"literal",strlen("literal")+1,1)
|
|
// strrchr:
|
|
// * strrchr(s,c) -> reverse_offset_of_in(c,s)
|
|
// (if c is a constant integer and s is a constant string)
|
|
// * strrchr(s1,0) -> strchr(s1,0)
|
|
//
|
|
// strncat:
|
|
// * strncat(x,y,0) -> x
|
|
// * strncat(x,y,0) -> x (if strlen(y) = 0)
|
|
// * strncat(x,y,l) -> strcat(x,y) (if y and l are constants an l > strlen(y))
|
|
//
|
|
// strncpy:
|
|
// * strncpy(d,s,0) -> d
|
|
// * strncpy(d,s,l) -> memcpy(d,s,l,1)
|
|
// (if s and l are constants)
|
|
//
|
|
// strpbrk:
|
|
// * strpbrk(s,a) -> offset_in_for(s,a)
|
|
// (if s and a are both constant strings)
|
|
// * strpbrk(s,"") -> 0
|
|
// * strpbrk(s,a) -> strchr(s,a[0]) (if a is constant string of length 1)
|
|
//
|
|
// strspn, strcspn:
|
|
// * strspn(s,a) -> const_int (if both args are constant)
|
|
// * strspn("",a) -> 0
|
|
// * strspn(s,"") -> 0
|
|
// * strcspn(s,a) -> const_int (if both args are constant)
|
|
// * strcspn("",a) -> 0
|
|
// * strcspn(s,"") -> strlen(a)
|
|
//
|
|
// strstr:
|
|
// * strstr(x,x) -> x
|
|
// * strstr(s1,s2) -> offset_of_s2_in(s1)
|
|
// (if s1 and s2 are constant strings)
|
|
//
|
|
// tan, tanf, tanl:
|
|
// * tan(atan(x)) -> x
|
|
//
|
|
// trunc, truncf, truncl:
|
|
// * trunc(cnst) -> cnst'
|
|
//
|
|
//
|
|
}
|