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701073e58e
attribute and function argument attribute synthesizing and propagating. As with the other uses of this attribute, the goal remains a best-effort (no guarantees) attempt to not optimize the function or assume things about the function when optimizing. This is particularly useful for compiler testing, bisecting miscompiles, triaging things, etc. I was hitting specific issues using optnone to isolate test code from a test driver for my fuzz testing, and this is one step of fixing that. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215538 91177308-0d34-0410-b5e6-96231b3b80d8
1713 lines
54 KiB
C++
1713 lines
54 KiB
C++
//===- FunctionAttrs.cpp - Pass which marks functions attributes ----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// 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 simple interprocedural pass which walks the
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// call-graph, looking for functions which do not access or only read
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// non-local memory, and marking them readnone/readonly. It does the
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// same with function arguments independently, marking them readonly/
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// readnone/nocapture. Finally, well-known library call declarations
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// are marked with all attributes that are consistent with the
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// function's standard definition. This pass is implemented as a
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// bottom-up traversal of the call-graph.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/IPO.h"
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#include "llvm/ADT/SCCIterator.h"
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#include "llvm/ADT/SetVector.h"
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#include "llvm/ADT/SmallSet.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/Analysis/AliasAnalysis.h"
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#include "llvm/Analysis/CallGraph.h"
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#include "llvm/Analysis/CallGraphSCCPass.h"
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#include "llvm/Analysis/CaptureTracking.h"
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#include "llvm/IR/GlobalVariable.h"
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#include "llvm/IR/InstIterator.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/Target/TargetLibraryInfo.h"
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using namespace llvm;
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#define DEBUG_TYPE "functionattrs"
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STATISTIC(NumReadNone, "Number of functions marked readnone");
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STATISTIC(NumReadOnly, "Number of functions marked readonly");
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STATISTIC(NumNoCapture, "Number of arguments marked nocapture");
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STATISTIC(NumReadNoneArg, "Number of arguments marked readnone");
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STATISTIC(NumReadOnlyArg, "Number of arguments marked readonly");
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STATISTIC(NumNoAlias, "Number of function returns marked noalias");
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STATISTIC(NumAnnotated, "Number of attributes added to library functions");
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namespace {
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struct FunctionAttrs : public CallGraphSCCPass {
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static char ID; // Pass identification, replacement for typeid
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FunctionAttrs() : CallGraphSCCPass(ID), AA(nullptr) {
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initializeFunctionAttrsPass(*PassRegistry::getPassRegistry());
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}
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// runOnSCC - Analyze the SCC, performing the transformation if possible.
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bool runOnSCC(CallGraphSCC &SCC) override;
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// AddReadAttrs - Deduce readonly/readnone attributes for the SCC.
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bool AddReadAttrs(const CallGraphSCC &SCC);
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// AddArgumentAttrs - Deduce nocapture attributes for the SCC.
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bool AddArgumentAttrs(const CallGraphSCC &SCC);
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// IsFunctionMallocLike - Does this function allocate new memory?
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bool IsFunctionMallocLike(Function *F,
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SmallPtrSet<Function*, 8> &) const;
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// AddNoAliasAttrs - Deduce noalias attributes for the SCC.
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bool AddNoAliasAttrs(const CallGraphSCC &SCC);
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// Utility methods used by inferPrototypeAttributes to add attributes
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// and maintain annotation statistics.
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void setDoesNotAccessMemory(Function &F) {
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if (!F.doesNotAccessMemory()) {
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F.setDoesNotAccessMemory();
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++NumAnnotated;
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}
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}
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void setOnlyReadsMemory(Function &F) {
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if (!F.onlyReadsMemory()) {
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F.setOnlyReadsMemory();
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++NumAnnotated;
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}
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}
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void setDoesNotThrow(Function &F) {
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if (!F.doesNotThrow()) {
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F.setDoesNotThrow();
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++NumAnnotated;
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}
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}
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void setDoesNotCapture(Function &F, unsigned n) {
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if (!F.doesNotCapture(n)) {
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F.setDoesNotCapture(n);
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++NumAnnotated;
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}
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}
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void setOnlyReadsMemory(Function &F, unsigned n) {
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if (!F.onlyReadsMemory(n)) {
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F.setOnlyReadsMemory(n);
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++NumAnnotated;
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}
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}
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void setDoesNotAlias(Function &F, unsigned n) {
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if (!F.doesNotAlias(n)) {
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F.setDoesNotAlias(n);
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++NumAnnotated;
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}
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}
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// inferPrototypeAttributes - Analyze the name and prototype of the
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// given function and set any applicable attributes. Returns true
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// if any attributes were set and false otherwise.
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bool inferPrototypeAttributes(Function &F);
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// annotateLibraryCalls - Adds attributes to well-known standard library
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// call declarations.
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bool annotateLibraryCalls(const CallGraphSCC &SCC);
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.setPreservesCFG();
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AU.addRequired<AliasAnalysis>();
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AU.addRequired<TargetLibraryInfo>();
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CallGraphSCCPass::getAnalysisUsage(AU);
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}
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private:
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AliasAnalysis *AA;
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TargetLibraryInfo *TLI;
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};
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}
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char FunctionAttrs::ID = 0;
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INITIALIZE_PASS_BEGIN(FunctionAttrs, "functionattrs",
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"Deduce function attributes", false, false)
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INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
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INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
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INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
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INITIALIZE_PASS_END(FunctionAttrs, "functionattrs",
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"Deduce function attributes", false, false)
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Pass *llvm::createFunctionAttrsPass() { return new FunctionAttrs(); }
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/// AddReadAttrs - Deduce readonly/readnone attributes for the SCC.
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bool FunctionAttrs::AddReadAttrs(const CallGraphSCC &SCC) {
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SmallPtrSet<Function*, 8> SCCNodes;
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// Fill SCCNodes with the elements of the SCC. Used for quickly
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// looking up whether a given CallGraphNode is in this SCC.
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for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I)
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SCCNodes.insert((*I)->getFunction());
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// Check if any of the functions in the SCC read or write memory. If they
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// write memory then they can't be marked readnone or readonly.
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bool ReadsMemory = false;
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for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
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Function *F = (*I)->getFunction();
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if (!F || F->hasFnAttribute(Attribute::OptimizeNone))
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// External node or node we don't want to optimize - assume it may write
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// memory and give up.
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return false;
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AliasAnalysis::ModRefBehavior MRB = AA->getModRefBehavior(F);
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if (MRB == AliasAnalysis::DoesNotAccessMemory)
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// Already perfect!
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continue;
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// Definitions with weak linkage may be overridden at linktime with
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// something that writes memory, so treat them like declarations.
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if (F->isDeclaration() || F->mayBeOverridden()) {
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if (!AliasAnalysis::onlyReadsMemory(MRB))
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// May write memory. Just give up.
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return false;
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ReadsMemory = true;
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continue;
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}
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// Scan the function body for instructions that may read or write memory.
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for (inst_iterator II = inst_begin(F), E = inst_end(F); II != E; ++II) {
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Instruction *I = &*II;
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// Some instructions can be ignored even if they read or write memory.
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// Detect these now, skipping to the next instruction if one is found.
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CallSite CS(cast<Value>(I));
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if (CS) {
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// Ignore calls to functions in the same SCC.
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if (CS.getCalledFunction() && SCCNodes.count(CS.getCalledFunction()))
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continue;
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AliasAnalysis::ModRefBehavior MRB = AA->getModRefBehavior(CS);
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// If the call doesn't access arbitrary memory, we may be able to
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// figure out something.
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if (AliasAnalysis::onlyAccessesArgPointees(MRB)) {
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// If the call does access argument pointees, check each argument.
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if (AliasAnalysis::doesAccessArgPointees(MRB))
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// Check whether all pointer arguments point to local memory, and
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// ignore calls that only access local memory.
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for (CallSite::arg_iterator CI = CS.arg_begin(), CE = CS.arg_end();
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CI != CE; ++CI) {
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Value *Arg = *CI;
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if (Arg->getType()->isPointerTy()) {
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AAMDNodes AAInfo;
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I->getAAMetadata(AAInfo);
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AliasAnalysis::Location Loc(Arg,
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AliasAnalysis::UnknownSize, AAInfo);
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if (!AA->pointsToConstantMemory(Loc, /*OrLocal=*/true)) {
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if (MRB & AliasAnalysis::Mod)
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// Writes non-local memory. Give up.
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return false;
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if (MRB & AliasAnalysis::Ref)
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// Ok, it reads non-local memory.
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ReadsMemory = true;
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}
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}
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}
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continue;
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}
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// The call could access any memory. If that includes writes, give up.
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if (MRB & AliasAnalysis::Mod)
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return false;
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// If it reads, note it.
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if (MRB & AliasAnalysis::Ref)
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ReadsMemory = true;
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continue;
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} else if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
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// Ignore non-volatile loads from local memory. (Atomic is okay here.)
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if (!LI->isVolatile()) {
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AliasAnalysis::Location Loc = AA->getLocation(LI);
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if (AA->pointsToConstantMemory(Loc, /*OrLocal=*/true))
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continue;
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}
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} else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
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// Ignore non-volatile stores to local memory. (Atomic is okay here.)
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if (!SI->isVolatile()) {
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AliasAnalysis::Location Loc = AA->getLocation(SI);
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if (AA->pointsToConstantMemory(Loc, /*OrLocal=*/true))
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continue;
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}
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} else if (VAArgInst *VI = dyn_cast<VAArgInst>(I)) {
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// Ignore vaargs on local memory.
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AliasAnalysis::Location Loc = AA->getLocation(VI);
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if (AA->pointsToConstantMemory(Loc, /*OrLocal=*/true))
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continue;
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}
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// Any remaining instructions need to be taken seriously! Check if they
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// read or write memory.
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if (I->mayWriteToMemory())
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// Writes memory. Just give up.
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return false;
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// If this instruction may read memory, remember that.
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ReadsMemory |= I->mayReadFromMemory();
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}
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}
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// Success! Functions in this SCC do not access memory, or only read memory.
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// Give them the appropriate attribute.
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bool MadeChange = false;
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for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
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Function *F = (*I)->getFunction();
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if (F->doesNotAccessMemory())
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// Already perfect!
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continue;
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if (F->onlyReadsMemory() && ReadsMemory)
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// No change.
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continue;
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MadeChange = true;
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// Clear out any existing attributes.
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AttrBuilder B;
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B.addAttribute(Attribute::ReadOnly)
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.addAttribute(Attribute::ReadNone);
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F->removeAttributes(AttributeSet::FunctionIndex,
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AttributeSet::get(F->getContext(),
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AttributeSet::FunctionIndex, B));
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// Add in the new attribute.
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F->addAttribute(AttributeSet::FunctionIndex,
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ReadsMemory ? Attribute::ReadOnly : Attribute::ReadNone);
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if (ReadsMemory)
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++NumReadOnly;
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else
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++NumReadNone;
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}
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return MadeChange;
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}
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namespace {
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// For a given pointer Argument, this retains a list of Arguments of functions
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// in the same SCC that the pointer data flows into. We use this to build an
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// SCC of the arguments.
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struct ArgumentGraphNode {
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Argument *Definition;
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SmallVector<ArgumentGraphNode*, 4> Uses;
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};
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class ArgumentGraph {
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// We store pointers to ArgumentGraphNode objects, so it's important that
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// that they not move around upon insert.
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typedef std::map<Argument*, ArgumentGraphNode> ArgumentMapTy;
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ArgumentMapTy ArgumentMap;
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// There is no root node for the argument graph, in fact:
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// void f(int *x, int *y) { if (...) f(x, y); }
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// is an example where the graph is disconnected. The SCCIterator requires a
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// single entry point, so we maintain a fake ("synthetic") root node that
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// uses every node. Because the graph is directed and nothing points into
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// the root, it will not participate in any SCCs (except for its own).
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ArgumentGraphNode SyntheticRoot;
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public:
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ArgumentGraph() { SyntheticRoot.Definition = nullptr; }
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typedef SmallVectorImpl<ArgumentGraphNode*>::iterator iterator;
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iterator begin() { return SyntheticRoot.Uses.begin(); }
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iterator end() { return SyntheticRoot.Uses.end(); }
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ArgumentGraphNode *getEntryNode() { return &SyntheticRoot; }
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ArgumentGraphNode *operator[](Argument *A) {
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ArgumentGraphNode &Node = ArgumentMap[A];
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Node.Definition = A;
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SyntheticRoot.Uses.push_back(&Node);
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return &Node;
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}
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};
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// This tracker checks whether callees are in the SCC, and if so it does not
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// consider that a capture, instead adding it to the "Uses" list and
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// continuing with the analysis.
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struct ArgumentUsesTracker : public CaptureTracker {
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ArgumentUsesTracker(const SmallPtrSet<Function*, 8> &SCCNodes)
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: Captured(false), SCCNodes(SCCNodes) {}
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void tooManyUses() override { Captured = true; }
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bool captured(const Use *U) override {
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CallSite CS(U->getUser());
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if (!CS.getInstruction()) { Captured = true; return true; }
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Function *F = CS.getCalledFunction();
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if (!F || !SCCNodes.count(F)) { Captured = true; return true; }
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bool Found = false;
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Function::arg_iterator AI = F->arg_begin(), AE = F->arg_end();
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for (CallSite::arg_iterator PI = CS.arg_begin(), PE = CS.arg_end();
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PI != PE; ++PI, ++AI) {
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if (AI == AE) {
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assert(F->isVarArg() && "More params than args in non-varargs call");
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Captured = true;
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return true;
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}
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if (PI == U) {
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Uses.push_back(AI);
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Found = true;
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break;
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}
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}
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assert(Found && "Capturing call-site captured nothing?");
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(void)Found;
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return false;
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}
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bool Captured; // True only if certainly captured (used outside our SCC).
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SmallVector<Argument*, 4> Uses; // Uses within our SCC.
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const SmallPtrSet<Function*, 8> &SCCNodes;
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};
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}
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namespace llvm {
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template<> struct GraphTraits<ArgumentGraphNode*> {
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typedef ArgumentGraphNode NodeType;
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typedef SmallVectorImpl<ArgumentGraphNode*>::iterator ChildIteratorType;
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static inline NodeType *getEntryNode(NodeType *A) { return A; }
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static inline ChildIteratorType child_begin(NodeType *N) {
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return N->Uses.begin();
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}
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static inline ChildIteratorType child_end(NodeType *N) {
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return N->Uses.end();
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}
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};
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template<> struct GraphTraits<ArgumentGraph*>
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: public GraphTraits<ArgumentGraphNode*> {
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static NodeType *getEntryNode(ArgumentGraph *AG) {
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return AG->getEntryNode();
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}
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static ChildIteratorType nodes_begin(ArgumentGraph *AG) {
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return AG->begin();
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}
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static ChildIteratorType nodes_end(ArgumentGraph *AG) {
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return AG->end();
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}
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};
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}
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// Returns Attribute::None, Attribute::ReadOnly or Attribute::ReadNone.
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static Attribute::AttrKind
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determinePointerReadAttrs(Argument *A,
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const SmallPtrSet<Argument*, 8> &SCCNodes) {
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SmallVector<Use*, 32> Worklist;
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SmallSet<Use*, 32> Visited;
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int Count = 0;
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// inalloca arguments are always clobbered by the call.
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if (A->hasInAllocaAttr())
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return Attribute::None;
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bool IsRead = false;
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// We don't need to track IsWritten. If A is written to, return immediately.
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for (Use &U : A->uses()) {
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if (Count++ >= 20)
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return Attribute::None;
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Visited.insert(&U);
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Worklist.push_back(&U);
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}
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while (!Worklist.empty()) {
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Use *U = Worklist.pop_back_val();
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Instruction *I = cast<Instruction>(U->getUser());
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Value *V = U->get();
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switch (I->getOpcode()) {
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case Instruction::BitCast:
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case Instruction::GetElementPtr:
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case Instruction::PHI:
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case Instruction::Select:
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case Instruction::AddrSpaceCast:
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// The original value is not read/written via this if the new value isn't.
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for (Use &UU : I->uses())
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if (Visited.insert(&UU))
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Worklist.push_back(&UU);
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break;
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case Instruction::Call:
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case Instruction::Invoke: {
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bool Captures = true;
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if (I->getType()->isVoidTy())
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Captures = false;
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auto AddUsersToWorklistIfCapturing = [&] {
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if (Captures)
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for (Use &UU : I->uses())
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if (Visited.insert(&UU))
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Worklist.push_back(&UU);
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};
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CallSite CS(I);
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if (CS.doesNotAccessMemory()) {
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AddUsersToWorklistIfCapturing();
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continue;
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}
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Function *F = CS.getCalledFunction();
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if (!F) {
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if (CS.onlyReadsMemory()) {
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IsRead = true;
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AddUsersToWorklistIfCapturing();
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continue;
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}
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return Attribute::None;
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}
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Function::arg_iterator AI = F->arg_begin(), AE = F->arg_end();
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CallSite::arg_iterator B = CS.arg_begin(), E = CS.arg_end();
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for (CallSite::arg_iterator A = B; A != E; ++A, ++AI) {
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if (A->get() == V) {
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if (AI == AE) {
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assert(F->isVarArg() &&
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"More params than args in non-varargs call.");
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return Attribute::None;
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}
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Captures &= !CS.doesNotCapture(A - B);
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if (SCCNodes.count(AI))
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continue;
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if (!CS.onlyReadsMemory() && !CS.onlyReadsMemory(A - B))
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return Attribute::None;
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if (!CS.doesNotAccessMemory(A - B))
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IsRead = true;
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}
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}
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AddUsersToWorklistIfCapturing();
|
|
break;
|
|
}
|
|
|
|
case Instruction::Load:
|
|
IsRead = true;
|
|
break;
|
|
|
|
case Instruction::ICmp:
|
|
case Instruction::Ret:
|
|
break;
|
|
|
|
default:
|
|
return Attribute::None;
|
|
}
|
|
}
|
|
|
|
return IsRead ? Attribute::ReadOnly : Attribute::ReadNone;
|
|
}
|
|
|
|
/// AddArgumentAttrs - Deduce nocapture attributes for the SCC.
|
|
bool FunctionAttrs::AddArgumentAttrs(const CallGraphSCC &SCC) {
|
|
bool Changed = false;
|
|
|
|
SmallPtrSet<Function*, 8> SCCNodes;
|
|
|
|
// Fill SCCNodes with the elements of the SCC. Used for quickly
|
|
// looking up whether a given CallGraphNode is in this SCC.
|
|
for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
|
|
Function *F = (*I)->getFunction();
|
|
if (F && !F->isDeclaration() && !F->mayBeOverridden() &&
|
|
!F->hasFnAttribute(Attribute::OptimizeNone))
|
|
SCCNodes.insert(F);
|
|
}
|
|
|
|
ArgumentGraph AG;
|
|
|
|
AttrBuilder B;
|
|
B.addAttribute(Attribute::NoCapture);
|
|
|
|
// Check each function in turn, determining which pointer arguments are not
|
|
// captured.
|
|
for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
|
|
Function *F = (*I)->getFunction();
|
|
|
|
if (!F || F->hasFnAttribute(Attribute::OptimizeNone))
|
|
// External node or function we're trying not to optimize - only a problem
|
|
// for arguments that we pass to it.
|
|
continue;
|
|
|
|
// Definitions with weak linkage may be overridden at linktime with
|
|
// something that captures pointers, so treat them like declarations.
|
|
if (F->isDeclaration() || F->mayBeOverridden())
|
|
continue;
|
|
|
|
// Functions that are readonly (or readnone) and nounwind and don't return
|
|
// a value can't capture arguments. Don't analyze them.
|
|
if (F->onlyReadsMemory() && F->doesNotThrow() &&
|
|
F->getReturnType()->isVoidTy()) {
|
|
for (Function::arg_iterator A = F->arg_begin(), E = F->arg_end();
|
|
A != E; ++A) {
|
|
if (A->getType()->isPointerTy() && !A->hasNoCaptureAttr()) {
|
|
A->addAttr(AttributeSet::get(F->getContext(), A->getArgNo() + 1, B));
|
|
++NumNoCapture;
|
|
Changed = true;
|
|
}
|
|
}
|
|
continue;
|
|
}
|
|
|
|
for (Function::arg_iterator A = F->arg_begin(), E = F->arg_end();
|
|
A != E; ++A) {
|
|
if (!A->getType()->isPointerTy()) continue;
|
|
bool HasNonLocalUses = false;
|
|
if (!A->hasNoCaptureAttr()) {
|
|
ArgumentUsesTracker Tracker(SCCNodes);
|
|
PointerMayBeCaptured(A, &Tracker);
|
|
if (!Tracker.Captured) {
|
|
if (Tracker.Uses.empty()) {
|
|
// If it's trivially not captured, mark it nocapture now.
|
|
A->addAttr(AttributeSet::get(F->getContext(), A->getArgNo()+1, B));
|
|
++NumNoCapture;
|
|
Changed = true;
|
|
} else {
|
|
// If it's not trivially captured and not trivially not captured,
|
|
// then it must be calling into another function in our SCC. Save
|
|
// its particulars for Argument-SCC analysis later.
|
|
ArgumentGraphNode *Node = AG[A];
|
|
for (SmallVectorImpl<Argument*>::iterator UI = Tracker.Uses.begin(),
|
|
UE = Tracker.Uses.end(); UI != UE; ++UI) {
|
|
Node->Uses.push_back(AG[*UI]);
|
|
if (*UI != A)
|
|
HasNonLocalUses = true;
|
|
}
|
|
}
|
|
}
|
|
// Otherwise, it's captured. Don't bother doing SCC analysis on it.
|
|
}
|
|
if (!HasNonLocalUses && !A->onlyReadsMemory()) {
|
|
// Can we determine that it's readonly/readnone without doing an SCC?
|
|
// Note that we don't allow any calls at all here, or else our result
|
|
// will be dependent on the iteration order through the functions in the
|
|
// SCC.
|
|
SmallPtrSet<Argument*, 8> Self;
|
|
Self.insert(A);
|
|
Attribute::AttrKind R = determinePointerReadAttrs(A, Self);
|
|
if (R != Attribute::None) {
|
|
AttrBuilder B;
|
|
B.addAttribute(R);
|
|
A->addAttr(AttributeSet::get(A->getContext(), A->getArgNo() + 1, B));
|
|
Changed = true;
|
|
R == Attribute::ReadOnly ? ++NumReadOnlyArg : ++NumReadNoneArg;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// The graph we've collected is partial because we stopped scanning for
|
|
// argument uses once we solved the argument trivially. These partial nodes
|
|
// show up as ArgumentGraphNode objects with an empty Uses list, and for
|
|
// these nodes the final decision about whether they capture has already been
|
|
// made. If the definition doesn't have a 'nocapture' attribute by now, it
|
|
// captures.
|
|
|
|
for (scc_iterator<ArgumentGraph*> I = scc_begin(&AG); !I.isAtEnd(); ++I) {
|
|
const std::vector<ArgumentGraphNode *> &ArgumentSCC = *I;
|
|
if (ArgumentSCC.size() == 1) {
|
|
if (!ArgumentSCC[0]->Definition) continue; // synthetic root node
|
|
|
|
// eg. "void f(int* x) { if (...) f(x); }"
|
|
if (ArgumentSCC[0]->Uses.size() == 1 &&
|
|
ArgumentSCC[0]->Uses[0] == ArgumentSCC[0]) {
|
|
Argument *A = ArgumentSCC[0]->Definition;
|
|
A->addAttr(AttributeSet::get(A->getContext(), A->getArgNo() + 1, B));
|
|
++NumNoCapture;
|
|
Changed = true;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
bool SCCCaptured = false;
|
|
for (auto I = ArgumentSCC.begin(), E = ArgumentSCC.end();
|
|
I != E && !SCCCaptured; ++I) {
|
|
ArgumentGraphNode *Node = *I;
|
|
if (Node->Uses.empty()) {
|
|
if (!Node->Definition->hasNoCaptureAttr())
|
|
SCCCaptured = true;
|
|
}
|
|
}
|
|
if (SCCCaptured) continue;
|
|
|
|
SmallPtrSet<Argument*, 8> ArgumentSCCNodes;
|
|
// Fill ArgumentSCCNodes with the elements of the ArgumentSCC. Used for
|
|
// quickly looking up whether a given Argument is in this ArgumentSCC.
|
|
for (auto I = ArgumentSCC.begin(), E = ArgumentSCC.end(); I != E; ++I) {
|
|
ArgumentSCCNodes.insert((*I)->Definition);
|
|
}
|
|
|
|
for (auto I = ArgumentSCC.begin(), E = ArgumentSCC.end();
|
|
I != E && !SCCCaptured; ++I) {
|
|
ArgumentGraphNode *N = *I;
|
|
for (SmallVectorImpl<ArgumentGraphNode*>::iterator UI = N->Uses.begin(),
|
|
UE = N->Uses.end(); UI != UE; ++UI) {
|
|
Argument *A = (*UI)->Definition;
|
|
if (A->hasNoCaptureAttr() || ArgumentSCCNodes.count(A))
|
|
continue;
|
|
SCCCaptured = true;
|
|
break;
|
|
}
|
|
}
|
|
if (SCCCaptured) continue;
|
|
|
|
for (unsigned i = 0, e = ArgumentSCC.size(); i != e; ++i) {
|
|
Argument *A = ArgumentSCC[i]->Definition;
|
|
A->addAttr(AttributeSet::get(A->getContext(), A->getArgNo() + 1, B));
|
|
++NumNoCapture;
|
|
Changed = true;
|
|
}
|
|
|
|
// We also want to compute readonly/readnone. With a small number of false
|
|
// negatives, we can assume that any pointer which is captured isn't going
|
|
// to be provably readonly or readnone, since by definition we can't
|
|
// analyze all uses of a captured pointer.
|
|
//
|
|
// The false negatives happen when the pointer is captured by a function
|
|
// that promises readonly/readnone behaviour on the pointer, then the
|
|
// pointer's lifetime ends before anything that writes to arbitrary memory.
|
|
// Also, a readonly/readnone pointer may be returned, but returning a
|
|
// pointer is capturing it.
|
|
|
|
Attribute::AttrKind ReadAttr = Attribute::ReadNone;
|
|
for (unsigned i = 0, e = ArgumentSCC.size(); i != e; ++i) {
|
|
Argument *A = ArgumentSCC[i]->Definition;
|
|
Attribute::AttrKind K = determinePointerReadAttrs(A, ArgumentSCCNodes);
|
|
if (K == Attribute::ReadNone)
|
|
continue;
|
|
if (K == Attribute::ReadOnly) {
|
|
ReadAttr = Attribute::ReadOnly;
|
|
continue;
|
|
}
|
|
ReadAttr = K;
|
|
break;
|
|
}
|
|
|
|
if (ReadAttr != Attribute::None) {
|
|
AttrBuilder B;
|
|
B.addAttribute(ReadAttr);
|
|
for (unsigned i = 0, e = ArgumentSCC.size(); i != e; ++i) {
|
|
Argument *A = ArgumentSCC[i]->Definition;
|
|
A->addAttr(AttributeSet::get(A->getContext(), A->getArgNo() + 1, B));
|
|
ReadAttr == Attribute::ReadOnly ? ++NumReadOnlyArg : ++NumReadNoneArg;
|
|
Changed = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
return Changed;
|
|
}
|
|
|
|
/// IsFunctionMallocLike - A function is malloc-like if it returns either null
|
|
/// or a pointer that doesn't alias any other pointer visible to the caller.
|
|
bool FunctionAttrs::IsFunctionMallocLike(Function *F,
|
|
SmallPtrSet<Function*, 8> &SCCNodes) const {
|
|
SmallSetVector<Value *, 8> FlowsToReturn;
|
|
for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I)
|
|
if (ReturnInst *Ret = dyn_cast<ReturnInst>(I->getTerminator()))
|
|
FlowsToReturn.insert(Ret->getReturnValue());
|
|
|
|
for (unsigned i = 0; i != FlowsToReturn.size(); ++i) {
|
|
Value *RetVal = FlowsToReturn[i];
|
|
|
|
if (Constant *C = dyn_cast<Constant>(RetVal)) {
|
|
if (!C->isNullValue() && !isa<UndefValue>(C))
|
|
return false;
|
|
|
|
continue;
|
|
}
|
|
|
|
if (isa<Argument>(RetVal))
|
|
return false;
|
|
|
|
if (Instruction *RVI = dyn_cast<Instruction>(RetVal))
|
|
switch (RVI->getOpcode()) {
|
|
// Extend the analysis by looking upwards.
|
|
case Instruction::BitCast:
|
|
case Instruction::GetElementPtr:
|
|
case Instruction::AddrSpaceCast:
|
|
FlowsToReturn.insert(RVI->getOperand(0));
|
|
continue;
|
|
case Instruction::Select: {
|
|
SelectInst *SI = cast<SelectInst>(RVI);
|
|
FlowsToReturn.insert(SI->getTrueValue());
|
|
FlowsToReturn.insert(SI->getFalseValue());
|
|
continue;
|
|
}
|
|
case Instruction::PHI: {
|
|
PHINode *PN = cast<PHINode>(RVI);
|
|
for (int i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
|
|
FlowsToReturn.insert(PN->getIncomingValue(i));
|
|
continue;
|
|
}
|
|
|
|
// Check whether the pointer came from an allocation.
|
|
case Instruction::Alloca:
|
|
break;
|
|
case Instruction::Call:
|
|
case Instruction::Invoke: {
|
|
CallSite CS(RVI);
|
|
if (CS.paramHasAttr(0, Attribute::NoAlias))
|
|
break;
|
|
if (CS.getCalledFunction() &&
|
|
SCCNodes.count(CS.getCalledFunction()))
|
|
break;
|
|
} // fall-through
|
|
default:
|
|
return false; // Did not come from an allocation.
|
|
}
|
|
|
|
if (PointerMayBeCaptured(RetVal, false, /*StoreCaptures=*/false))
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/// AddNoAliasAttrs - Deduce noalias attributes for the SCC.
|
|
bool FunctionAttrs::AddNoAliasAttrs(const CallGraphSCC &SCC) {
|
|
SmallPtrSet<Function*, 8> SCCNodes;
|
|
|
|
// Fill SCCNodes with the elements of the SCC. Used for quickly
|
|
// looking up whether a given CallGraphNode is in this SCC.
|
|
for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I)
|
|
SCCNodes.insert((*I)->getFunction());
|
|
|
|
// Check each function in turn, determining which functions return noalias
|
|
// pointers.
|
|
for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
|
|
Function *F = (*I)->getFunction();
|
|
|
|
if (!F || F->hasFnAttribute(Attribute::OptimizeNone))
|
|
// External node or node we don't want to optimize - skip it;
|
|
return false;
|
|
|
|
// Already noalias.
|
|
if (F->doesNotAlias(0))
|
|
continue;
|
|
|
|
// Definitions with weak linkage may be overridden at linktime, so
|
|
// treat them like declarations.
|
|
if (F->isDeclaration() || F->mayBeOverridden())
|
|
return false;
|
|
|
|
// We annotate noalias return values, which are only applicable to
|
|
// pointer types.
|
|
if (!F->getReturnType()->isPointerTy())
|
|
continue;
|
|
|
|
if (!IsFunctionMallocLike(F, SCCNodes))
|
|
return false;
|
|
}
|
|
|
|
bool MadeChange = false;
|
|
for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
|
|
Function *F = (*I)->getFunction();
|
|
if (F->doesNotAlias(0) || !F->getReturnType()->isPointerTy())
|
|
continue;
|
|
|
|
F->setDoesNotAlias(0);
|
|
++NumNoAlias;
|
|
MadeChange = true;
|
|
}
|
|
|
|
return MadeChange;
|
|
}
|
|
|
|
/// inferPrototypeAttributes - Analyze the name and prototype of the
|
|
/// given function and set any applicable attributes. Returns true
|
|
/// if any attributes were set and false otherwise.
|
|
bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
|
|
if (F.hasFnAttribute(Attribute::OptimizeNone))
|
|
return false;
|
|
|
|
FunctionType *FTy = F.getFunctionType();
|
|
LibFunc::Func TheLibFunc;
|
|
if (!(TLI->getLibFunc(F.getName(), TheLibFunc) && TLI->has(TheLibFunc)))
|
|
return false;
|
|
|
|
switch (TheLibFunc) {
|
|
case LibFunc::strlen:
|
|
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setOnlyReadsMemory(F);
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::strchr:
|
|
case LibFunc::strrchr:
|
|
if (FTy->getNumParams() != 2 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isIntegerTy())
|
|
return false;
|
|
setOnlyReadsMemory(F);
|
|
setDoesNotThrow(F);
|
|
break;
|
|
case LibFunc::strtol:
|
|
case LibFunc::strtod:
|
|
case LibFunc::strtof:
|
|
case LibFunc::strtoul:
|
|
case LibFunc::strtoll:
|
|
case LibFunc::strtold:
|
|
case LibFunc::strtoull:
|
|
if (FTy->getNumParams() < 2 ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::strcpy:
|
|
case LibFunc::stpcpy:
|
|
case LibFunc::strcat:
|
|
case LibFunc::strncat:
|
|
case LibFunc::strncpy:
|
|
case LibFunc::stpncpy:
|
|
if (FTy->getNumParams() < 2 ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::strxfrm:
|
|
if (FTy->getNumParams() != 3 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::strcmp: //0,1
|
|
case LibFunc::strspn: // 0,1
|
|
case LibFunc::strncmp: // 0,1
|
|
case LibFunc::strcspn: //0,1
|
|
case LibFunc::strcoll: //0,1
|
|
case LibFunc::strcasecmp: // 0,1
|
|
case LibFunc::strncasecmp: //
|
|
if (FTy->getNumParams() < 2 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setOnlyReadsMemory(F);
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
case LibFunc::strstr:
|
|
case LibFunc::strpbrk:
|
|
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setOnlyReadsMemory(F);
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
case LibFunc::strtok:
|
|
case LibFunc::strtok_r:
|
|
if (FTy->getNumParams() < 2 || !FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::scanf:
|
|
if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::setbuf:
|
|
case LibFunc::setvbuf:
|
|
if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::strdup:
|
|
case LibFunc::strndup:
|
|
if (FTy->getNumParams() < 1 || !FTy->getReturnType()->isPointerTy() ||
|
|
!FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotAlias(F, 0);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::stat:
|
|
case LibFunc::statvfs:
|
|
if (FTy->getNumParams() < 2 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::sscanf:
|
|
if (FTy->getNumParams() < 2 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::sprintf:
|
|
if (FTy->getNumParams() < 2 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::snprintf:
|
|
if (FTy->getNumParams() != 3 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(2)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 3);
|
|
setOnlyReadsMemory(F, 3);
|
|
break;
|
|
case LibFunc::setitimer:
|
|
if (FTy->getNumParams() != 3 ||
|
|
!FTy->getParamType(1)->isPointerTy() ||
|
|
!FTy->getParamType(2)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 2);
|
|
setDoesNotCapture(F, 3);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::system:
|
|
if (FTy->getNumParams() != 1 ||
|
|
!FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
// May throw; "system" is a valid pthread cancellation point.
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::malloc:
|
|
if (FTy->getNumParams() != 1 ||
|
|
!FTy->getReturnType()->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotAlias(F, 0);
|
|
break;
|
|
case LibFunc::memcmp:
|
|
if (FTy->getNumParams() != 3 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setOnlyReadsMemory(F);
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
case LibFunc::memchr:
|
|
case LibFunc::memrchr:
|
|
if (FTy->getNumParams() != 3)
|
|
return false;
|
|
setOnlyReadsMemory(F);
|
|
setDoesNotThrow(F);
|
|
break;
|
|
case LibFunc::modf:
|
|
case LibFunc::modff:
|
|
case LibFunc::modfl:
|
|
if (FTy->getNumParams() < 2 ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
case LibFunc::memcpy:
|
|
case LibFunc::memccpy:
|
|
case LibFunc::memmove:
|
|
if (FTy->getNumParams() < 2 ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::memalign:
|
|
if (!FTy->getReturnType()->isPointerTy())
|
|
return false;
|
|
setDoesNotAlias(F, 0);
|
|
break;
|
|
case LibFunc::mkdir:
|
|
if (FTy->getNumParams() == 0 ||
|
|
!FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::mktime:
|
|
if (FTy->getNumParams() == 0 ||
|
|
!FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::realloc:
|
|
if (FTy->getNumParams() != 2 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getReturnType()->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotAlias(F, 0);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::read:
|
|
if (FTy->getNumParams() != 3 ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
// May throw; "read" is a valid pthread cancellation point.
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
case LibFunc::rewind:
|
|
if (FTy->getNumParams() < 1 ||
|
|
!FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::rmdir:
|
|
case LibFunc::remove:
|
|
case LibFunc::realpath:
|
|
if (FTy->getNumParams() < 1 ||
|
|
!FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::rename:
|
|
if (FTy->getNumParams() < 2 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::readlink:
|
|
if (FTy->getNumParams() < 2 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::write:
|
|
if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
// May throw; "write" is a valid pthread cancellation point.
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::bcopy:
|
|
if (FTy->getNumParams() != 3 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::bcmp:
|
|
if (FTy->getNumParams() != 3 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setOnlyReadsMemory(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
case LibFunc::bzero:
|
|
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::calloc:
|
|
if (FTy->getNumParams() != 2 ||
|
|
!FTy->getReturnType()->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotAlias(F, 0);
|
|
break;
|
|
case LibFunc::chmod:
|
|
case LibFunc::chown:
|
|
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::ctermid:
|
|
case LibFunc::clearerr:
|
|
case LibFunc::closedir:
|
|
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::atoi:
|
|
case LibFunc::atol:
|
|
case LibFunc::atof:
|
|
case LibFunc::atoll:
|
|
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setOnlyReadsMemory(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::access:
|
|
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::fopen:
|
|
if (FTy->getNumParams() != 2 ||
|
|
!FTy->getReturnType()->isPointerTy() ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotAlias(F, 0);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::fdopen:
|
|
if (FTy->getNumParams() != 2 ||
|
|
!FTy->getReturnType()->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotAlias(F, 0);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::feof:
|
|
case LibFunc::free:
|
|
case LibFunc::fseek:
|
|
case LibFunc::ftell:
|
|
case LibFunc::fgetc:
|
|
case LibFunc::fseeko:
|
|
case LibFunc::ftello:
|
|
case LibFunc::fileno:
|
|
case LibFunc::fflush:
|
|
case LibFunc::fclose:
|
|
case LibFunc::fsetpos:
|
|
case LibFunc::flockfile:
|
|
case LibFunc::funlockfile:
|
|
case LibFunc::ftrylockfile:
|
|
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::ferror:
|
|
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F);
|
|
break;
|
|
case LibFunc::fputc:
|
|
case LibFunc::fstat:
|
|
case LibFunc::frexp:
|
|
case LibFunc::frexpf:
|
|
case LibFunc::frexpl:
|
|
case LibFunc::fstatvfs:
|
|
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
case LibFunc::fgets:
|
|
if (FTy->getNumParams() != 3 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(2)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 3);
|
|
break;
|
|
case LibFunc::fread:
|
|
if (FTy->getNumParams() != 4 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(3)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 4);
|
|
break;
|
|
case LibFunc::fwrite:
|
|
if (FTy->getNumParams() != 4 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(3)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 4);
|
|
break;
|
|
case LibFunc::fputs:
|
|
if (FTy->getNumParams() < 2 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::fscanf:
|
|
case LibFunc::fprintf:
|
|
if (FTy->getNumParams() < 2 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::fgetpos:
|
|
if (FTy->getNumParams() < 2 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
case LibFunc::getc:
|
|
case LibFunc::getlogin_r:
|
|
case LibFunc::getc_unlocked:
|
|
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::getenv:
|
|
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setOnlyReadsMemory(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::gets:
|
|
case LibFunc::getchar:
|
|
setDoesNotThrow(F);
|
|
break;
|
|
case LibFunc::getitimer:
|
|
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
case LibFunc::getpwnam:
|
|
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::ungetc:
|
|
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
case LibFunc::uname:
|
|
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::unlink:
|
|
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::unsetenv:
|
|
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::utime:
|
|
case LibFunc::utimes:
|
|
if (FTy->getNumParams() != 2 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::putc:
|
|
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
case LibFunc::puts:
|
|
case LibFunc::printf:
|
|
case LibFunc::perror:
|
|
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::pread:
|
|
if (FTy->getNumParams() != 4 || !FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
// May throw; "pread" is a valid pthread cancellation point.
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
case LibFunc::pwrite:
|
|
if (FTy->getNumParams() != 4 || !FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
// May throw; "pwrite" is a valid pthread cancellation point.
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::putchar:
|
|
setDoesNotThrow(F);
|
|
break;
|
|
case LibFunc::popen:
|
|
if (FTy->getNumParams() != 2 ||
|
|
!FTy->getReturnType()->isPointerTy() ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotAlias(F, 0);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::pclose:
|
|
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::vscanf:
|
|
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::vsscanf:
|
|
if (FTy->getNumParams() != 3 ||
|
|
!FTy->getParamType(1)->isPointerTy() ||
|
|
!FTy->getParamType(2)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::vfscanf:
|
|
if (FTy->getNumParams() != 3 ||
|
|
!FTy->getParamType(1)->isPointerTy() ||
|
|
!FTy->getParamType(2)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::valloc:
|
|
if (!FTy->getReturnType()->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotAlias(F, 0);
|
|
break;
|
|
case LibFunc::vprintf:
|
|
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::vfprintf:
|
|
case LibFunc::vsprintf:
|
|
if (FTy->getNumParams() != 3 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::vsnprintf:
|
|
if (FTy->getNumParams() != 4 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(2)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 3);
|
|
setOnlyReadsMemory(F, 3);
|
|
break;
|
|
case LibFunc::open:
|
|
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
// May throw; "open" is a valid pthread cancellation point.
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::opendir:
|
|
if (FTy->getNumParams() != 1 ||
|
|
!FTy->getReturnType()->isPointerTy() ||
|
|
!FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotAlias(F, 0);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::tmpfile:
|
|
if (!FTy->getReturnType()->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotAlias(F, 0);
|
|
break;
|
|
case LibFunc::times:
|
|
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::htonl:
|
|
case LibFunc::htons:
|
|
case LibFunc::ntohl:
|
|
case LibFunc::ntohs:
|
|
setDoesNotThrow(F);
|
|
setDoesNotAccessMemory(F);
|
|
break;
|
|
case LibFunc::lstat:
|
|
if (FTy->getNumParams() != 2 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::lchown:
|
|
if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::qsort:
|
|
if (FTy->getNumParams() != 4 || !FTy->getParamType(3)->isPointerTy())
|
|
return false;
|
|
// May throw; places call through function pointer.
|
|
setDoesNotCapture(F, 4);
|
|
break;
|
|
case LibFunc::dunder_strdup:
|
|
case LibFunc::dunder_strndup:
|
|
if (FTy->getNumParams() < 1 ||
|
|
!FTy->getReturnType()->isPointerTy() ||
|
|
!FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotAlias(F, 0);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::dunder_strtok_r:
|
|
if (FTy->getNumParams() != 3 ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::under_IO_getc:
|
|
if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::under_IO_putc:
|
|
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
case LibFunc::dunder_isoc99_scanf:
|
|
if (FTy->getNumParams() < 1 ||
|
|
!FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::stat64:
|
|
case LibFunc::lstat64:
|
|
case LibFunc::statvfs64:
|
|
if (FTy->getNumParams() < 1 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::dunder_isoc99_sscanf:
|
|
if (FTy->getNumParams() < 1 ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::fopen64:
|
|
if (FTy->getNumParams() != 2 ||
|
|
!FTy->getReturnType()->isPointerTy() ||
|
|
!FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotAlias(F, 0);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
setOnlyReadsMemory(F, 1);
|
|
setOnlyReadsMemory(F, 2);
|
|
break;
|
|
case LibFunc::fseeko64:
|
|
case LibFunc::ftello64:
|
|
if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
break;
|
|
case LibFunc::tmpfile64:
|
|
if (!FTy->getReturnType()->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotAlias(F, 0);
|
|
break;
|
|
case LibFunc::fstat64:
|
|
case LibFunc::fstatvfs64:
|
|
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
case LibFunc::open64:
|
|
if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy())
|
|
return false;
|
|
// May throw; "open" is a valid pthread cancellation point.
|
|
setDoesNotCapture(F, 1);
|
|
setOnlyReadsMemory(F, 1);
|
|
break;
|
|
case LibFunc::gettimeofday:
|
|
if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy() ||
|
|
!FTy->getParamType(1)->isPointerTy())
|
|
return false;
|
|
// Currently some platforms have the restrict keyword on the arguments to
|
|
// gettimeofday. To be conservative, do not add noalias to gettimeofday's
|
|
// arguments.
|
|
setDoesNotThrow(F);
|
|
setDoesNotCapture(F, 1);
|
|
setDoesNotCapture(F, 2);
|
|
break;
|
|
default:
|
|
// Didn't mark any attributes.
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/// annotateLibraryCalls - Adds attributes to well-known standard library
|
|
/// call declarations.
|
|
bool FunctionAttrs::annotateLibraryCalls(const CallGraphSCC &SCC) {
|
|
bool MadeChange = false;
|
|
|
|
// Check each function in turn annotating well-known library function
|
|
// declarations with attributes.
|
|
for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
|
|
Function *F = (*I)->getFunction();
|
|
|
|
if (F && F->isDeclaration())
|
|
MadeChange |= inferPrototypeAttributes(*F);
|
|
}
|
|
|
|
return MadeChange;
|
|
}
|
|
|
|
bool FunctionAttrs::runOnSCC(CallGraphSCC &SCC) {
|
|
AA = &getAnalysis<AliasAnalysis>();
|
|
TLI = &getAnalysis<TargetLibraryInfo>();
|
|
|
|
bool Changed = annotateLibraryCalls(SCC);
|
|
Changed |= AddReadAttrs(SCC);
|
|
Changed |= AddArgumentAttrs(SCC);
|
|
Changed |= AddNoAliasAttrs(SCC);
|
|
return Changed;
|
|
}
|