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llvm-6502/lib/Transforms/Scalar/SimplifyLibCalls.cpp
Bill Wendling 143d46476c Implement the NoBuiltin attribute. 
The 'nobuiltin' attribute is applied to call sites to indicate that LLVM should
not treat the callee function as a built-in function. I.e., it shouldn't try to
replace that function with different code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175835 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-22 00:12:35 +00:00

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//===- SimplifyLibCalls.cpp - Optimize specific well-known library calls --===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements a simple pass that applies a variety of small
// optimizations for calls to specific well-known function calls (e.g. runtime
// library functions). Any optimization that takes the very simple form
// "replace call to library function with simpler code that provides the same
// result" belongs in this file.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "simplify-libcalls"
#include "llvm/Transforms/Scalar.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Config/config.h" // FIXME: Shouldn't depend on host!
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Transforms/Utils/BuildLibCalls.h"
using namespace llvm;
STATISTIC(NumAnnotated, "Number of attributes added to library functions");
//===----------------------------------------------------------------------===//
// Optimizer Base Class
//===----------------------------------------------------------------------===//
/// This class is the abstract base class for the set of optimizations that
/// corresponds to one library call.
namespace {
class LibCallOptimization {
protected:
Function *Caller;
const DataLayout *TD;
const TargetLibraryInfo *TLI;
LLVMContext* Context;
public:
LibCallOptimization() { }
virtual ~LibCallOptimization() {}
/// CallOptimizer - This pure virtual method is implemented by base classes to
/// do various optimizations. If this returns null then no transformation was
/// performed. If it returns CI, then it transformed the call and CI is to be
/// deleted. If it returns something else, replace CI with the new value and
/// delete CI.
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B)
=0;
Value *OptimizeCall(CallInst *CI, const DataLayout *TD,
const TargetLibraryInfo *TLI, IRBuilder<> &B) {
Caller = CI->getParent()->getParent();
this->TD = TD;
this->TLI = TLI;
if (CI->getCalledFunction())
Context = &CI->getCalledFunction()->getContext();
// We never change the calling convention.
if (CI->getCallingConv() != llvm::CallingConv::C)
return NULL;
return CallOptimizer(CI->getCalledFunction(), CI, B);
}
};
} // End anonymous namespace.
//===----------------------------------------------------------------------===//
// SimplifyLibCalls Pass Implementation
//===----------------------------------------------------------------------===//
namespace {
/// This pass optimizes well known library functions from libc and libm.
///
class SimplifyLibCalls : public FunctionPass {
TargetLibraryInfo *TLI;
StringMap<LibCallOptimization*> Optimizations;
bool Modified; // This is only used by doInitialization.
public:
static char ID; // Pass identification
SimplifyLibCalls() : FunctionPass(ID) {
initializeSimplifyLibCallsPass(*PassRegistry::getPassRegistry());
}
void AddOpt(LibFunc::Func F, LibCallOptimization* Opt);
void AddOpt(LibFunc::Func F1, LibFunc::Func F2, LibCallOptimization* Opt);
void InitOptimizations();
bool runOnFunction(Function &F);
void setDoesNotAccessMemory(Function &F);
void setOnlyReadsMemory(Function &F);
void setDoesNotThrow(Function &F);
void setDoesNotCapture(Function &F, unsigned n);
void setDoesNotAlias(Function &F, unsigned n);
bool doInitialization(Module &M);
void inferPrototypeAttributes(Function &F);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<TargetLibraryInfo>();
}
};
} // end anonymous namespace.
char SimplifyLibCalls::ID = 0;
INITIALIZE_PASS_BEGIN(SimplifyLibCalls, "simplify-libcalls",
"Simplify well-known library calls", false, false)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
INITIALIZE_PASS_END(SimplifyLibCalls, "simplify-libcalls",
"Simplify well-known library calls", false, false)
// Public interface to the Simplify LibCalls pass.
FunctionPass *llvm::createSimplifyLibCallsPass() {
return new SimplifyLibCalls();
}
void SimplifyLibCalls::AddOpt(LibFunc::Func F, LibCallOptimization* Opt) {
if (TLI->has(F))
Optimizations[TLI->getName(F)] = Opt;
}
void SimplifyLibCalls::AddOpt(LibFunc::Func F1, LibFunc::Func F2,
LibCallOptimization* Opt) {
if (TLI->has(F1) && TLI->has(F2))
Optimizations[TLI->getName(F1)] = Opt;
}
/// Optimizations - Populate the Optimizations map with all the optimizations
/// we know.
void SimplifyLibCalls::InitOptimizations() {
}
/// runOnFunction - Top level algorithm.
///
bool SimplifyLibCalls::runOnFunction(Function &F) {
TLI = &getAnalysis<TargetLibraryInfo>();
if (Optimizations.empty())
InitOptimizations();
const DataLayout *TD = getAnalysisIfAvailable<DataLayout>();
IRBuilder<> Builder(F.getContext());
bool Changed = false;
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
// Ignore non-calls.
CallInst *CI = dyn_cast<CallInst>(I++);
if (!CI || CI->hasFnAttr(Attribute::NoBuiltin)) continue;
// Ignore indirect calls and calls to non-external functions.
Function *Callee = CI->getCalledFunction();
if (Callee == 0 || !Callee->isDeclaration() ||
!(Callee->hasExternalLinkage() || Callee->hasDLLImportLinkage()))
continue;
// Ignore unknown calls.
LibCallOptimization *LCO = Optimizations.lookup(Callee->getName());
if (!LCO) continue;
// Set the builder to the instruction after the call.
Builder.SetInsertPoint(BB, I);
// Use debug location of CI for all new instructions.
Builder.SetCurrentDebugLocation(CI->getDebugLoc());
// Try to optimize this call.
Value *Result = LCO->OptimizeCall(CI, TD, TLI, Builder);
if (Result == 0) continue;
DEBUG(dbgs() << "SimplifyLibCalls simplified: " << *CI;
dbgs() << " into: " << *Result << "\n");
// Something changed!
Changed = true;
// Inspect the instruction after the call (which was potentially just
// added) next.
I = CI; ++I;
if (CI != Result && !CI->use_empty()) {
CI->replaceAllUsesWith(Result);
if (!Result->hasName())
Result->takeName(CI);
}
CI->eraseFromParent();
}
}
return Changed;
}
// Utility methods for doInitialization.
void SimplifyLibCalls::setDoesNotAccessMemory(Function &F) {
if (!F.doesNotAccessMemory()) {
F.setDoesNotAccessMemory();
++NumAnnotated;
Modified = true;
}
}
void SimplifyLibCalls::setOnlyReadsMemory(Function &F) {
if (!F.onlyReadsMemory()) {
F.setOnlyReadsMemory();
++NumAnnotated;
Modified = true;
}
}
void SimplifyLibCalls::setDoesNotThrow(Function &F) {
if (!F.doesNotThrow()) {
F.setDoesNotThrow();
++NumAnnotated;
Modified = true;
}
}
void SimplifyLibCalls::setDoesNotCapture(Function &F, unsigned n) {
if (!F.doesNotCapture(n)) {
F.setDoesNotCapture(n);
++NumAnnotated;
Modified = true;
}
}
void SimplifyLibCalls::setDoesNotAlias(Function &F, unsigned n) {
if (!F.doesNotAlias(n)) {
F.setDoesNotAlias(n);
++NumAnnotated;
Modified = true;
}
}
void SimplifyLibCalls::inferPrototypeAttributes(Function &F) {
FunctionType *FTy = F.getFunctionType();
StringRef Name = F.getName();
switch (Name[0]) {
case 's':
if (Name == "strlen") {
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return;
setOnlyReadsMemory(F);
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
} else if (Name == "strchr" ||
Name == "strrchr") {
if (FTy->getNumParams() != 2 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isIntegerTy())
return;
setOnlyReadsMemory(F);
setDoesNotThrow(F);
} else if (Name == "strcpy" ||
Name == "stpcpy" ||
Name == "strcat" ||
Name == "strtol" ||
Name == "strtod" ||
Name == "strtof" ||
Name == "strtoul" ||
Name == "strtoll" ||
Name == "strtold" ||
Name == "strncat" ||
Name == "strncpy" ||
Name == "stpncpy" ||
Name == "strtoull") {
if (FTy->getNumParams() < 2 ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 2);
} else if (Name == "strxfrm") {
if (FTy->getNumParams() != 3 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
} else if (Name == "strcmp" ||
Name == "strspn" ||
Name == "strncmp" ||
Name == "strcspn" ||
Name == "strcoll" ||
Name == "strcasecmp" ||
Name == "strncasecmp") {
if (FTy->getNumParams() < 2 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setOnlyReadsMemory(F);
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
} else if (Name == "strstr" ||
Name == "strpbrk") {
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return;
setOnlyReadsMemory(F);
setDoesNotThrow(F);
setDoesNotCapture(F, 2);
} else if (Name == "strtok" ||
Name == "strtok_r") {
if (FTy->getNumParams() < 2 || !FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 2);
} else if (Name == "scanf" ||
Name == "setbuf" ||
Name == "setvbuf") {
if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
} else if (Name == "strdup" ||
Name == "strndup") {
if (FTy->getNumParams() < 1 || !FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotAlias(F, 0);
setDoesNotCapture(F, 1);
} else if (Name == "stat" ||
Name == "sscanf" ||
Name == "sprintf" ||
Name == "statvfs") {
if (FTy->getNumParams() < 2 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
} else if (Name == "snprintf") {
if (FTy->getNumParams() != 3 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(2)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 3);
} else if (Name == "setitimer") {
if (FTy->getNumParams() != 3 ||
!FTy->getParamType(1)->isPointerTy() ||
!FTy->getParamType(2)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 2);
setDoesNotCapture(F, 3);
} else if (Name == "system") {
if (FTy->getNumParams() != 1 ||
!FTy->getParamType(0)->isPointerTy())
return;
// May throw; "system" is a valid pthread cancellation point.
setDoesNotCapture(F, 1);
}
break;
case 'm':
if (Name == "malloc") {
if (FTy->getNumParams() != 1 ||
!FTy->getReturnType()->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotAlias(F, 0);
} else if (Name == "memcmp") {
if (FTy->getNumParams() != 3 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setOnlyReadsMemory(F);
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
} else if (Name == "memchr" ||
Name == "memrchr") {
if (FTy->getNumParams() != 3)
return;
setOnlyReadsMemory(F);
setDoesNotThrow(F);
} else if (Name == "modf" ||
Name == "modff" ||
Name == "modfl" ||
Name == "memcpy" ||
Name == "memccpy" ||
Name == "memmove") {
if (FTy->getNumParams() < 2 ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 2);
} else if (Name == "memalign") {
if (!FTy->getReturnType()->isPointerTy())
return;
setDoesNotAlias(F, 0);
} else if (Name == "mkdir" ||
Name == "mktime") {
if (FTy->getNumParams() == 0 ||
!FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
}
break;
case 'r':
if (Name == "realloc") {
if (FTy->getNumParams() != 2 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getReturnType()->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotAlias(F, 0);
setDoesNotCapture(F, 1);
} else if (Name == "read") {
if (FTy->getNumParams() != 3 ||
!FTy->getParamType(1)->isPointerTy())
return;
// May throw; "read" is a valid pthread cancellation point.
setDoesNotCapture(F, 2);
} else if (Name == "rmdir" ||
Name == "rewind" ||
Name == "remove" ||
Name == "realpath") {
if (FTy->getNumParams() < 1 ||
!FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
} else if (Name == "rename" ||
Name == "readlink") {
if (FTy->getNumParams() < 2 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
}
break;
case 'w':
if (Name == "write") {
if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy())
return;
// May throw; "write" is a valid pthread cancellation point.
setDoesNotCapture(F, 2);
}
break;
case 'b':
if (Name == "bcopy") {
if (FTy->getNumParams() != 3 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
} else if (Name == "bcmp") {
if (FTy->getNumParams() != 3 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setOnlyReadsMemory(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
} else if (Name == "bzero") {
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
}
break;
case 'c':
if (Name == "calloc") {
if (FTy->getNumParams() != 2 ||
!FTy->getReturnType()->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotAlias(F, 0);
} else if (Name == "chmod" ||
Name == "chown" ||
Name == "ctermid" ||
Name == "clearerr" ||
Name == "closedir") {
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
}
break;
case 'a':
if (Name == "atoi" ||
Name == "atol" ||
Name == "atof" ||
Name == "atoll") {
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setOnlyReadsMemory(F);
setDoesNotCapture(F, 1);
} else if (Name == "access") {
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
}
break;
case 'f':
if (Name == "fopen") {
if (FTy->getNumParams() != 2 ||
!FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotAlias(F, 0);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
} else if (Name == "fdopen") {
if (FTy->getNumParams() != 2 ||
!FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotAlias(F, 0);
setDoesNotCapture(F, 2);
} else if (Name == "feof" ||
Name == "free" ||
Name == "fseek" ||
Name == "ftell" ||
Name == "fgetc" ||
Name == "fseeko" ||
Name == "ftello" ||
Name == "fileno" ||
Name == "fflush" ||
Name == "fclose" ||
Name == "fsetpos" ||
Name == "flockfile" ||
Name == "funlockfile" ||
Name == "ftrylockfile") {
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
} else if (Name == "ferror") {
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setOnlyReadsMemory(F);
} else if (Name == "fputc" ||
Name == "fstat" ||
Name == "frexp" ||
Name == "frexpf" ||
Name == "frexpl" ||
Name == "fstatvfs") {
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 2);
} else if (Name == "fgets") {
if (FTy->getNumParams() != 3 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(2)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 3);
} else if (Name == "fread" ||
Name == "fwrite") {
if (FTy->getNumParams() != 4 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(3)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 4);
} else if (Name == "fputs" ||
Name == "fscanf" ||
Name == "fprintf" ||
Name == "fgetpos") {
if (FTy->getNumParams() < 2 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
}
break;
case 'g':
if (Name == "getc" ||
Name == "getlogin_r" ||
Name == "getc_unlocked") {
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
} else if (Name == "getenv") {
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setOnlyReadsMemory(F);
setDoesNotCapture(F, 1);
} else if (Name == "gets" ||
Name == "getchar") {
setDoesNotThrow(F);
} else if (Name == "getitimer") {
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 2);
} else if (Name == "getpwnam") {
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
}
break;
case 'u':
if (Name == "ungetc") {
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 2);
} else if (Name == "uname" ||
Name == "unlink" ||
Name == "unsetenv") {
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
} else if (Name == "utime" ||
Name == "utimes") {
if (FTy->getNumParams() != 2 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
}
break;
case 'p':
if (Name == "putc") {
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 2);
} else if (Name == "puts" ||
Name == "printf" ||
Name == "perror") {
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
} else if (Name == "pread" ||
Name == "pwrite") {
if (FTy->getNumParams() != 4 || !FTy->getParamType(1)->isPointerTy())
return;
// May throw; these are valid pthread cancellation points.
setDoesNotCapture(F, 2);
} else if (Name == "putchar") {
setDoesNotThrow(F);
} else if (Name == "popen") {
if (FTy->getNumParams() != 2 ||
!FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotAlias(F, 0);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
} else if (Name == "pclose") {
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
}
break;
case 'v':
if (Name == "vscanf") {
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
} else if (Name == "vsscanf" ||
Name == "vfscanf") {
if (FTy->getNumParams() != 3 ||
!FTy->getParamType(1)->isPointerTy() ||
!FTy->getParamType(2)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
} else if (Name == "valloc") {
if (!FTy->getReturnType()->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotAlias(F, 0);
} else if (Name == "vprintf") {
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
} else if (Name == "vfprintf" ||
Name == "vsprintf") {
if (FTy->getNumParams() != 3 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
} else if (Name == "vsnprintf") {
if (FTy->getNumParams() != 4 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(2)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 3);
}
break;
case 'o':
if (Name == "open") {
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy())
return;
// May throw; "open" is a valid pthread cancellation point.
setDoesNotCapture(F, 1);
} else if (Name == "opendir") {
if (FTy->getNumParams() != 1 ||
!FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotAlias(F, 0);
setDoesNotCapture(F, 1);
}
break;
case 't':
if (Name == "tmpfile") {
if (!FTy->getReturnType()->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotAlias(F, 0);
} else if (Name == "times") {
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
}
break;
case 'h':
if (Name == "htonl" ||
Name == "htons") {
setDoesNotThrow(F);
setDoesNotAccessMemory(F);
}
break;
case 'n':
if (Name == "ntohl" ||
Name == "ntohs") {
setDoesNotThrow(F);
setDoesNotAccessMemory(F);
}
break;
case 'l':
if (Name == "lstat") {
if (FTy->getNumParams() != 2 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
} else if (Name == "lchown") {
if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
}
break;
case 'q':
if (Name == "qsort") {
if (FTy->getNumParams() != 4 || !FTy->getParamType(3)->isPointerTy())
return;
// May throw; places call through function pointer.
setDoesNotCapture(F, 4);
}
break;
case '_':
if (Name == "__strdup" ||
Name == "__strndup") {
if (FTy->getNumParams() < 1 ||
!FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotAlias(F, 0);
setDoesNotCapture(F, 1);
} else if (Name == "__strtok_r") {
if (FTy->getNumParams() != 3 ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 2);
} else if (Name == "_IO_getc") {
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
} else if (Name == "_IO_putc") {
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 2);
}
break;
case 1:
if (Name == "\1__isoc99_scanf") {
if (FTy->getNumParams() < 1 ||
!FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
} else if (Name == "\1stat64" ||
Name == "\1lstat64" ||
Name == "\1statvfs64" ||
Name == "\1__isoc99_sscanf") {
if (FTy->getNumParams() < 1 ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
} else if (Name == "\1fopen64") {
if (FTy->getNumParams() != 2 ||
!FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotAlias(F, 0);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
} else if (Name == "\1fseeko64" ||
Name == "\1ftello64") {
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
} else if (Name == "\1tmpfile64") {
if (!FTy->getReturnType()->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotAlias(F, 0);
} else if (Name == "\1fstat64" ||
Name == "\1fstatvfs64") {
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
return;
setDoesNotThrow(F);
setDoesNotCapture(F, 2);
} else if (Name == "\1open64") {
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy())
return;
// May throw; "open" is a valid pthread cancellation point.
setDoesNotCapture(F, 1);
}
break;
}
}
/// doInitialization - Add attributes to well-known functions.
///
bool SimplifyLibCalls::doInitialization(Module &M) {
Modified = false;
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
Function &F = *I;
if (F.isDeclaration() && F.hasName())
inferPrototypeAttributes(F);
}
return Modified;
}
// 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)
//
// 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'
//
// 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)
//
// 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)
//
// strchr:
// * strchr(p, 0) -> strlen(p)
// tan, tanf, tanl:
// * tan(atan(x)) -> x
//
// trunc, truncf, truncl:
// * trunc(cnst) -> cnst'
//
//
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