//
// This file implements a simple interprocedural pass which walks the
// call-graph, looking for functions which do not access or only read
-// non-local memory, and marking them readnone/readonly. In addition,
-// it marks function arguments (of pointer type) 'nocapture' if a call
-// to the function does not create any copies of the pointer value that
-// outlive the call. This more or less means that the pointer is only
-// dereferenced, and not returned from the function or stored in a global.
-// Finally, well-known library call declarations are marked with all
-// attributes that are consistent with the function's standard definition.
-// This pass is implemented as a bottom-up traversal of the call-graph.
+// non-local memory, and marking them readnone/readonly. It does the
+// same with function arguments independently, marking them readonly/
+// readnone/nocapture. Finally, well-known library call declarations
+// are marked with all attributes that are consistent with the
+// function's standard definition. This pass is implemented as a
+// bottom-up traversal of the call-graph.
//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "functionattrs"
#include "llvm/Transforms/IPO.h"
#include "llvm/ADT/SCCIterator.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/BasicAliasAnalysis.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Analysis/CallGraphSCCPass.h"
#include "llvm/Analysis/CaptureTracking.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/InstIterator.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
-#include "llvm/Support/InstIterator.h"
-#include "llvm/Target/TargetLibraryInfo.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
using namespace llvm;
+#define DEBUG_TYPE "functionattrs"
+
STATISTIC(NumReadNone, "Number of functions marked readnone");
STATISTIC(NumReadOnly, "Number of functions marked readonly");
STATISTIC(NumNoCapture, "Number of arguments marked nocapture");
+STATISTIC(NumReadNoneArg, "Number of arguments marked readnone");
+STATISTIC(NumReadOnlyArg, "Number of arguments marked readonly");
STATISTIC(NumNoAlias, "Number of function returns marked noalias");
+STATISTIC(NumNonNullReturn, "Number of function returns marked nonnull");
STATISTIC(NumAnnotated, "Number of attributes added to library functions");
namespace {
- struct FunctionAttrs : public CallGraphSCCPass {
- static char ID; // Pass identification, replacement for typeid
- FunctionAttrs() : CallGraphSCCPass(ID), AA(0) {
- initializeFunctionAttrsPass(*PassRegistry::getPassRegistry());
- }
+struct FunctionAttrs : public CallGraphSCCPass {
+ static char ID; // Pass identification, replacement for typeid
+ FunctionAttrs() : CallGraphSCCPass(ID) {
+ initializeFunctionAttrsPass(*PassRegistry::getPassRegistry());
+ }
- // runOnSCC - Analyze the SCC, performing the transformation if possible.
- bool runOnSCC(CallGraphSCC &SCC);
+ bool runOnSCC(CallGraphSCC &SCC) override;
- // AddReadAttrs - Deduce readonly/readnone attributes for the SCC.
- bool AddReadAttrs(const CallGraphSCC &SCC);
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.setPreservesCFG();
+ AU.addRequired<AssumptionCacheTracker>();
+ AU.addRequired<TargetLibraryInfoWrapperPass>();
+ CallGraphSCCPass::getAnalysisUsage(AU);
+ }
- // AddNoCaptureAttrs - Deduce nocapture attributes for the SCC.
- bool AddNoCaptureAttrs(const CallGraphSCC &SCC);
+private:
+ TargetLibraryInfo *TLI;
- // IsFunctionMallocLike - Does this function allocate new memory?
- bool IsFunctionMallocLike(Function *F,
- SmallPtrSet<Function*, 8> &) const;
+ bool AddReadAttrs(const CallGraphSCC &SCC);
+ bool AddArgumentAttrs(const CallGraphSCC &SCC);
+ bool AddNoAliasAttrs(const CallGraphSCC &SCC);
+ bool AddNonNullAttrs(const CallGraphSCC &SCC);
+ bool annotateLibraryCalls(const CallGraphSCC &SCC);
+};
+}
- // AddNoAliasAttrs - Deduce noalias attributes for the SCC.
- bool AddNoAliasAttrs(const CallGraphSCC &SCC);
+char FunctionAttrs::ID = 0;
+INITIALIZE_PASS_BEGIN(FunctionAttrs, "functionattrs",
+ "Deduce function attributes", false, false)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
+INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
+INITIALIZE_PASS_END(FunctionAttrs, "functionattrs",
+ "Deduce function attributes", false, false)
- // Utility methods used by inferPrototypeAttributes to add attributes
- // and maintain annotation statistics.
+Pass *llvm::createFunctionAttrsPass() { return new FunctionAttrs(); }
- void setDoesNotAccessMemory(Function &F) {
- if (!F.doesNotAccessMemory()) {
- F.setDoesNotAccessMemory();
- ++NumAnnotated;
- }
- }
+namespace {
+/// The three kinds of memory access relevant to 'readonly' and
+/// 'readnone' attributes.
+enum MemoryAccessKind {
+ MAK_ReadNone = 0,
+ MAK_ReadOnly = 1,
+ MAK_MayWrite = 2
+};
+}
- void setOnlyReadsMemory(Function &F) {
- if (!F.onlyReadsMemory()) {
- F.setOnlyReadsMemory();
- ++NumAnnotated;
- }
- }
+static MemoryAccessKind
+checkFunctionMemoryAccess(Function &F, AAResults &AAR,
+ const SmallPtrSetImpl<Function *> &SCCNodes) {
+ FunctionModRefBehavior MRB = AAR.getModRefBehavior(&F);
+ if (MRB == FMRB_DoesNotAccessMemory)
+ // Already perfect!
+ return MAK_ReadNone;
+
+ // Definitions with weak linkage may be overridden at linktime with
+ // something that writes memory, so treat them like declarations.
+ if (F.isDeclaration() || F.mayBeOverridden()) {
+ if (AliasAnalysis::onlyReadsMemory(MRB))
+ return MAK_ReadOnly;
+
+ // Conservatively assume it writes to memory.
+ return MAK_MayWrite;
+ }
- void setDoesNotThrow(Function &F) {
- if (!F.doesNotThrow()) {
- F.setDoesNotThrow();
- ++NumAnnotated;
+ // Scan the function body for instructions that may read or write memory.
+ bool ReadsMemory = false;
+ for (inst_iterator II = inst_begin(F), E = inst_end(F); II != E; ++II) {
+ Instruction *I = &*II;
+
+ // Some instructions can be ignored even if they read or write memory.
+ // Detect these now, skipping to the next instruction if one is found.
+ CallSite CS(cast<Value>(I));
+ if (CS) {
+ // Ignore calls to functions in the same SCC.
+ if (CS.getCalledFunction() && SCCNodes.count(CS.getCalledFunction()))
+ continue;
+ FunctionModRefBehavior MRB = AAR.getModRefBehavior(CS);
+ // If the call doesn't access arbitrary memory, we may be able to
+ // figure out something.
+ if (AliasAnalysis::onlyAccessesArgPointees(MRB)) {
+ // If the call does access argument pointees, check each argument.
+ if (AliasAnalysis::doesAccessArgPointees(MRB))
+ // Check whether all pointer arguments point to local memory, and
+ // ignore calls that only access local memory.
+ for (CallSite::arg_iterator CI = CS.arg_begin(), CE = CS.arg_end();
+ CI != CE; ++CI) {
+ Value *Arg = *CI;
+ if (Arg->getType()->isPointerTy()) {
+ AAMDNodes AAInfo;
+ I->getAAMetadata(AAInfo);
+
+ MemoryLocation Loc(Arg, MemoryLocation::UnknownSize, AAInfo);
+ if (!AAR.pointsToConstantMemory(Loc, /*OrLocal=*/true)) {
+ if (MRB & MRI_Mod)
+ // Writes non-local memory. Give up.
+ return MAK_MayWrite;
+ if (MRB & MRI_Ref)
+ // Ok, it reads non-local memory.
+ ReadsMemory = true;
+ }
+ }
+ }
+ continue;
}
- }
-
- void setDoesNotCapture(Function &F, unsigned n) {
- if (!F.doesNotCapture(n)) {
- F.setDoesNotCapture(n);
- ++NumAnnotated;
+ // The call could access any memory. If that includes writes, give up.
+ if (MRB & MRI_Mod)
+ return MAK_MayWrite;
+ // If it reads, note it.
+ if (MRB & MRI_Ref)
+ ReadsMemory = true;
+ continue;
+ } else if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
+ // Ignore non-volatile loads from local memory. (Atomic is okay here.)
+ if (!LI->isVolatile()) {
+ MemoryLocation Loc = MemoryLocation::get(LI);
+ if (AAR.pointsToConstantMemory(Loc, /*OrLocal=*/true))
+ continue;
}
- }
-
- void setDoesNotAlias(Function &F, unsigned n) {
- if (!F.doesNotAlias(n)) {
- F.setDoesNotAlias(n);
- ++NumAnnotated;
+ } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
+ // Ignore non-volatile stores to local memory. (Atomic is okay here.)
+ if (!SI->isVolatile()) {
+ MemoryLocation Loc = MemoryLocation::get(SI);
+ if (AAR.pointsToConstantMemory(Loc, /*OrLocal=*/true))
+ continue;
}
+ } else if (VAArgInst *VI = dyn_cast<VAArgInst>(I)) {
+ // Ignore vaargs on local memory.
+ MemoryLocation Loc = MemoryLocation::get(VI);
+ if (AAR.pointsToConstantMemory(Loc, /*OrLocal=*/true))
+ continue;
}
- // 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 inferPrototypeAttributes(Function &F);
+ // Any remaining instructions need to be taken seriously! Check if they
+ // read or write memory.
+ if (I->mayWriteToMemory())
+ // Writes memory. Just give up.
+ return MAK_MayWrite;
- // annotateLibraryCalls - Adds attributes to well-known standard library
- // call declarations.
- bool annotateLibraryCalls(const CallGraphSCC &SCC);
-
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesCFG();
- AU.addRequired<AliasAnalysis>();
- AU.addRequired<TargetLibraryInfo>();
- CallGraphSCCPass::getAnalysisUsage(AU);
- }
+ // If this instruction may read memory, remember that.
+ ReadsMemory |= I->mayReadFromMemory();
+ }
- private:
- AliasAnalysis *AA;
- TargetLibraryInfo *TLI;
- };
+ return ReadsMemory ? MAK_ReadOnly : MAK_ReadNone;
}
-char FunctionAttrs::ID = 0;
-INITIALIZE_PASS_BEGIN(FunctionAttrs, "functionattrs",
- "Deduce function attributes", false, false)
-INITIALIZE_AG_DEPENDENCY(CallGraph)
-INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
-INITIALIZE_PASS_END(FunctionAttrs, "functionattrs",
- "Deduce function attributes", false, false)
-
-Pass *llvm::createFunctionAttrsPass() { return new FunctionAttrs(); }
-
-
-/// AddReadAttrs - Deduce readonly/readnone attributes for the SCC.
+/// Deduce readonly/readnone attributes for the SCC.
bool FunctionAttrs::AddReadAttrs(const CallGraphSCC &SCC) {
- SmallPtrSet<Function*, 8> SCCNodes;
+ 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 == 0)
- // External node - may write memory. Just give up.
+ if (!F || F->hasFnAttribute(Attribute::OptimizeNone))
+ // External node or node we don't want to optimize - assume it may write
+ // memory and give up.
return false;
- AliasAnalysis::ModRefBehavior MRB = AA->getModRefBehavior(F);
- if (MRB == AliasAnalysis::DoesNotAccessMemory)
- // Already perfect!
- continue;
+ // We need to manually construct BasicAA directly in order to disable its
+ // use of other function analyses.
+ BasicAAResult BAR(createLegacyPMBasicAAResult(*this, *F));
- // Definitions with weak linkage may be overridden at linktime with
- // something that writes memory, so treat them like declarations.
- if (F->isDeclaration() || F->mayBeOverridden()) {
- if (!AliasAnalysis::onlyReadsMemory(MRB))
- // May write memory. Just give up.
- return false;
+ // Construct our own AA results for this function. We do this manually to
+ // work around the limitations of the legacy pass manager.
+ AAResults AAR(createLegacyPMAAResults(*this, *F, BAR));
+ switch (checkFunctionMemoryAccess(*F, AAR, SCCNodes)) {
+ case MAK_MayWrite:
+ return false;
+ case MAK_ReadOnly:
ReadsMemory = true;
- continue;
- }
-
- // Scan the function body for instructions that may read or write memory.
- for (inst_iterator II = inst_begin(F), E = inst_end(F); II != E; ++II) {
- Instruction *I = &*II;
-
- // Some instructions can be ignored even if they read or write memory.
- // Detect these now, skipping to the next instruction if one is found.
- CallSite CS(cast<Value>(I));
- if (CS) {
- // Ignore calls to functions in the same SCC.
- if (CS.getCalledFunction() && SCCNodes.count(CS.getCalledFunction()))
- continue;
- AliasAnalysis::ModRefBehavior MRB = AA->getModRefBehavior(CS);
- // If the call doesn't access arbitrary memory, we may be able to
- // figure out something.
- if (AliasAnalysis::onlyAccessesArgPointees(MRB)) {
- // If the call does access argument pointees, check each argument.
- if (AliasAnalysis::doesAccessArgPointees(MRB))
- // Check whether all pointer arguments point to local memory, and
- // ignore calls that only access local memory.
- for (CallSite::arg_iterator CI = CS.arg_begin(), CE = CS.arg_end();
- CI != CE; ++CI) {
- Value *Arg = *CI;
- if (Arg->getType()->isPointerTy()) {
- AliasAnalysis::Location Loc(Arg,
- AliasAnalysis::UnknownSize,
- I->getMetadata(LLVMContext::MD_tbaa));
- if (!AA->pointsToConstantMemory(Loc, /*OrLocal=*/true)) {
- if (MRB & AliasAnalysis::Mod)
- // Writes non-local memory. Give up.
- return false;
- if (MRB & AliasAnalysis::Ref)
- // Ok, it reads non-local memory.
- ReadsMemory = true;
- }
- }
- }
- continue;
- }
- // The call could access any memory. If that includes writes, give up.
- if (MRB & AliasAnalysis::Mod)
- return false;
- // If it reads, note it.
- if (MRB & AliasAnalysis::Ref)
- ReadsMemory = true;
- continue;
- } else if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
- // Ignore non-volatile loads from local memory. (Atomic is okay here.)
- if (!LI->isVolatile()) {
- AliasAnalysis::Location Loc = AA->getLocation(LI);
- if (AA->pointsToConstantMemory(Loc, /*OrLocal=*/true))
- continue;
- }
- } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
- // Ignore non-volatile stores to local memory. (Atomic is okay here.)
- if (!SI->isVolatile()) {
- AliasAnalysis::Location Loc = AA->getLocation(SI);
- if (AA->pointsToConstantMemory(Loc, /*OrLocal=*/true))
- continue;
- }
- } else if (VAArgInst *VI = dyn_cast<VAArgInst>(I)) {
- // Ignore vaargs on local memory.
- AliasAnalysis::Location Loc = AA->getLocation(VI);
- if (AA->pointsToConstantMemory(Loc, /*OrLocal=*/true))
- continue;
- }
-
- // Any remaining instructions need to be taken seriously! Check if they
- // read or write memory.
- if (I->mayWriteToMemory())
- // Writes memory. Just give up.
- return false;
-
- // If this instruction may read memory, remember that.
- ReadsMemory |= I->mayReadFromMemory();
+ break;
+ case MAK_ReadNone:
+ // Nothing to do!
+ break;
}
}
// Clear out any existing attributes.
AttrBuilder B;
- B.addAttribute(Attribute::ReadOnly)
- .addAttribute(Attribute::ReadNone);
- F->removeAttributes(AttributeSet::FunctionIndex,
- AttributeSet::get(F->getContext(),
- AttributeSet::FunctionIndex, B));
+ B.addAttribute(Attribute::ReadOnly).addAttribute(Attribute::ReadNone);
+ F->removeAttributes(
+ AttributeSet::FunctionIndex,
+ AttributeSet::get(F->getContext(), AttributeSet::FunctionIndex, B));
// Add in the new attribute.
F->addAttribute(AttributeSet::FunctionIndex,
}
namespace {
- // For a given pointer Argument, this retains a list of Arguments of functions
- // in the same SCC that the pointer data flows into. We use this to build an
- // SCC of the arguments.
- struct ArgumentGraphNode {
- Argument *Definition;
- SmallVector<ArgumentGraphNode*, 4> Uses;
- };
-
- class ArgumentGraph {
- // We store pointers to ArgumentGraphNode objects, so it's important that
- // that they not move around upon insert.
- typedef std::map<Argument*, ArgumentGraphNode> ArgumentMapTy;
-
- ArgumentMapTy ArgumentMap;
-
- // There is no root node for the argument graph, in fact:
- // void f(int *x, int *y) { if (...) f(x, y); }
- // is an example where the graph is disconnected. The SCCIterator requires a
- // single entry point, so we maintain a fake ("synthetic") root node that
- // uses every node. Because the graph is directed and nothing points into
- // the root, it will not participate in any SCCs (except for its own).
- ArgumentGraphNode SyntheticRoot;
-
- public:
- ArgumentGraph() { SyntheticRoot.Definition = 0; }
-
- typedef SmallVectorImpl<ArgumentGraphNode*>::iterator iterator;
-
- iterator begin() { return SyntheticRoot.Uses.begin(); }
- iterator end() { return SyntheticRoot.Uses.end(); }
- ArgumentGraphNode *getEntryNode() { return &SyntheticRoot; }
-
- ArgumentGraphNode *operator[](Argument *A) {
- ArgumentGraphNode &Node = ArgumentMap[A];
- Node.Definition = A;
- SyntheticRoot.Uses.push_back(&Node);
- return &Node;
- }
- };
+/// For a given pointer Argument, this retains a list of Arguments of functions
+/// in the same SCC that the pointer data flows into. We use this to build an
+/// SCC of the arguments.
+struct ArgumentGraphNode {
+ Argument *Definition;
+ SmallVector<ArgumentGraphNode *, 4> Uses;
+};
+
+class ArgumentGraph {
+ // We store pointers to ArgumentGraphNode objects, so it's important that
+ // that they not move around upon insert.
+ typedef std::map<Argument *, ArgumentGraphNode> ArgumentMapTy;
+
+ ArgumentMapTy ArgumentMap;
+
+ // There is no root node for the argument graph, in fact:
+ // void f(int *x, int *y) { if (...) f(x, y); }
+ // is an example where the graph is disconnected. The SCCIterator requires a
+ // single entry point, so we maintain a fake ("synthetic") root node that
+ // uses every node. Because the graph is directed and nothing points into
+ // the root, it will not participate in any SCCs (except for its own).
+ ArgumentGraphNode SyntheticRoot;
+
+public:
+ ArgumentGraph() { SyntheticRoot.Definition = nullptr; }
+
+ typedef SmallVectorImpl<ArgumentGraphNode *>::iterator iterator;
+
+ iterator begin() { return SyntheticRoot.Uses.begin(); }
+ iterator end() { return SyntheticRoot.Uses.end(); }
+ ArgumentGraphNode *getEntryNode() { return &SyntheticRoot; }
+
+ ArgumentGraphNode *operator[](Argument *A) {
+ ArgumentGraphNode &Node = ArgumentMap[A];
+ Node.Definition = A;
+ SyntheticRoot.Uses.push_back(&Node);
+ return &Node;
+ }
+};
- // This tracker checks whether callees are in the SCC, and if so it does not
- // consider that a capture, instead adding it to the "Uses" list and
- // continuing with the analysis.
- struct ArgumentUsesTracker : public CaptureTracker {
- ArgumentUsesTracker(const SmallPtrSet<Function*, 8> &SCCNodes)
+/// This tracker checks whether callees are in the SCC, and if so it does not
+/// consider that a capture, instead adding it to the "Uses" list and
+/// continuing with the analysis.
+struct ArgumentUsesTracker : public CaptureTracker {
+ ArgumentUsesTracker(const SmallPtrSet<Function *, 8> &SCCNodes)
: Captured(false), SCCNodes(SCCNodes) {}
- void tooManyUses() { Captured = true; }
+ void tooManyUses() override { Captured = true; }
- bool captured(Use *U) {
- CallSite CS(U->getUser());
- if (!CS.getInstruction()) { Captured = true; return true; }
+ bool captured(const Use *U) override {
+ CallSite CS(U->getUser());
+ if (!CS.getInstruction()) {
+ Captured = true;
+ return true;
+ }
- Function *F = CS.getCalledFunction();
- if (!F || !SCCNodes.count(F)) { Captured = true; return true; }
+ Function *F = CS.getCalledFunction();
+ if (!F || !SCCNodes.count(F)) {
+ Captured = true;
+ return true;
+ }
- Function::arg_iterator AI = F->arg_begin(), AE = F->arg_end();
- for (CallSite::arg_iterator PI = CS.arg_begin(), PE = CS.arg_end();
- PI != PE; ++PI, ++AI) {
- if (AI == AE) {
- assert(F->isVarArg() && "More params than args in non-varargs call");
- Captured = true;
- return true;
- }
- if (PI == U) {
- Uses.push_back(AI);
- break;
- }
+ bool Found = false;
+ Function::arg_iterator AI = F->arg_begin(), AE = F->arg_end();
+ for (CallSite::arg_iterator PI = CS.arg_begin(), PE = CS.arg_end();
+ PI != PE; ++PI, ++AI) {
+ if (AI == AE) {
+ assert(F->isVarArg() && "More params than args in non-varargs call");
+ Captured = true;
+ return true;
+ }
+ if (PI == U) {
+ Uses.push_back(AI);
+ Found = true;
+ break;
}
- assert(!Uses.empty() && "Capturing call-site captured nothing?");
- return false;
}
+ assert(Found && "Capturing call-site captured nothing?");
+ (void)Found;
+ return false;
+ }
- bool Captured; // True only if certainly captured (used outside our SCC).
- SmallVector<Argument*, 4> Uses; // Uses within our SCC.
+ bool Captured; // True only if certainly captured (used outside our SCC).
+ SmallVector<Argument *, 4> Uses; // Uses within our SCC.
- const SmallPtrSet<Function*, 8> &SCCNodes;
- };
+ const SmallPtrSet<Function *, 8> &SCCNodes;
+};
}
namespace llvm {
- template<> struct GraphTraits<ArgumentGraphNode*> {
- typedef ArgumentGraphNode NodeType;
- typedef SmallVectorImpl<ArgumentGraphNode*>::iterator ChildIteratorType;
+template <> struct GraphTraits<ArgumentGraphNode *> {
+ typedef ArgumentGraphNode NodeType;
+ typedef SmallVectorImpl<ArgumentGraphNode *>::iterator ChildIteratorType;
- static inline NodeType *getEntryNode(NodeType *A) { return A; }
- static inline ChildIteratorType child_begin(NodeType *N) {
- return N->Uses.begin();
- }
- static inline ChildIteratorType child_end(NodeType *N) {
- return N->Uses.end();
- }
- };
- template<> struct GraphTraits<ArgumentGraph*>
- : public GraphTraits<ArgumentGraphNode*> {
- static NodeType *getEntryNode(ArgumentGraph *AG) {
- return AG->getEntryNode();
- }
- static ChildIteratorType nodes_begin(ArgumentGraph *AG) {
- return AG->begin();
+ static inline NodeType *getEntryNode(NodeType *A) { return A; }
+ static inline ChildIteratorType child_begin(NodeType *N) {
+ return N->Uses.begin();
+ }
+ static inline ChildIteratorType child_end(NodeType *N) {
+ return N->Uses.end();
+ }
+};
+template <>
+struct GraphTraits<ArgumentGraph *> : public GraphTraits<ArgumentGraphNode *> {
+ static NodeType *getEntryNode(ArgumentGraph *AG) {
+ return AG->getEntryNode();
+ }
+ static ChildIteratorType nodes_begin(ArgumentGraph *AG) {
+ return AG->begin();
+ }
+ static ChildIteratorType nodes_end(ArgumentGraph *AG) { return AG->end(); }
+};
+}
+
+/// Returns Attribute::None, Attribute::ReadOnly or Attribute::ReadNone.
+static Attribute::AttrKind
+determinePointerReadAttrs(Argument *A,
+ const SmallPtrSet<Argument *, 8> &SCCNodes) {
+
+ SmallVector<Use *, 32> Worklist;
+ SmallSet<Use *, 32> Visited;
+
+ // inalloca arguments are always clobbered by the call.
+ if (A->hasInAllocaAttr())
+ return Attribute::None;
+
+ bool IsRead = false;
+ // We don't need to track IsWritten. If A is written to, return immediately.
+
+ for (Use &U : A->uses()) {
+ Visited.insert(&U);
+ Worklist.push_back(&U);
+ }
+
+ while (!Worklist.empty()) {
+ Use *U = Worklist.pop_back_val();
+ Instruction *I = cast<Instruction>(U->getUser());
+ Value *V = U->get();
+
+ switch (I->getOpcode()) {
+ case Instruction::BitCast:
+ case Instruction::GetElementPtr:
+ case Instruction::PHI:
+ case Instruction::Select:
+ case Instruction::AddrSpaceCast:
+ // The original value is not read/written via this if the new value isn't.
+ for (Use &UU : I->uses())
+ if (Visited.insert(&UU).second)
+ Worklist.push_back(&UU);
+ break;
+
+ case Instruction::Call:
+ case Instruction::Invoke: {
+ bool Captures = true;
+
+ if (I->getType()->isVoidTy())
+ Captures = false;
+
+ auto AddUsersToWorklistIfCapturing = [&] {
+ if (Captures)
+ for (Use &UU : I->uses())
+ if (Visited.insert(&UU).second)
+ Worklist.push_back(&UU);
+ };
+
+ CallSite CS(I);
+ if (CS.doesNotAccessMemory()) {
+ AddUsersToWorklistIfCapturing();
+ continue;
+ }
+
+ Function *F = CS.getCalledFunction();
+ if (!F) {
+ if (CS.onlyReadsMemory()) {
+ IsRead = true;
+ AddUsersToWorklistIfCapturing();
+ continue;
+ }
+ return Attribute::None;
+ }
+
+ Function::arg_iterator AI = F->arg_begin(), AE = F->arg_end();
+ CallSite::arg_iterator B = CS.arg_begin(), E = CS.arg_end();
+ for (CallSite::arg_iterator A = B; A != E; ++A, ++AI) {
+ if (A->get() == V) {
+ if (AI == AE) {
+ assert(F->isVarArg() &&
+ "More params than args in non-varargs call.");
+ return Attribute::None;
+ }
+ Captures &= !CS.doesNotCapture(A - B);
+ if (SCCNodes.count(AI))
+ continue;
+ if (!CS.onlyReadsMemory() && !CS.onlyReadsMemory(A - B))
+ return Attribute::None;
+ if (!CS.doesNotAccessMemory(A - B))
+ IsRead = true;
+ }
+ }
+ AddUsersToWorklistIfCapturing();
+ break;
}
- static ChildIteratorType nodes_end(ArgumentGraph *AG) {
- return AG->end();
+
+ case Instruction::Load:
+ IsRead = true;
+ break;
+
+ case Instruction::ICmp:
+ case Instruction::Ret:
+ break;
+
+ default:
+ return Attribute::None;
}
- };
+ }
+
+ return IsRead ? Attribute::ReadOnly : Attribute::ReadNone;
}
-/// AddNoCaptureAttrs - Deduce nocapture attributes for the SCC.
-bool FunctionAttrs::AddNoCaptureAttrs(const CallGraphSCC &SCC) {
+/// Deduce nocapture attributes for the SCC.
+bool FunctionAttrs::AddArgumentAttrs(const CallGraphSCC &SCC) {
bool Changed = false;
- SmallPtrSet<Function*, 8> SCCNodes;
+ 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())
+ 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 == 0)
- // External node - only a problem for arguments that we pass to it.
+ 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
if (F->isDeclaration() || F->mayBeOverridden())
continue;
- SmallVector<AttributeSet, 8> AttrSets;
-
// 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())
- continue;
-
- AttributeSet In =
- F->getAttributes().getParamAttributes(A->getArgNo() + 1);
- AttrSets.push_back(In.addAttribute(F->getContext(), A->getArgNo() + 1,
- Attribute::NoCapture));
+ if (A->getType()->isPointerTy() && !A->hasNoCaptureAttr()) {
+ A->addAttr(AttributeSet::get(F->getContext(), A->getArgNo() + 1, B));
+ ++NumNoCapture;
+ Changed = true;
+ }
}
- } else {
- for (Function::arg_iterator A = F->arg_begin(), E = F->arg_end(); A != E;
- ++A) {
- if (!A->getType()->isPointerTy() || A->hasNoCaptureAttr())
- continue;
+ 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)
- continue; // It's captured. Don't bother doing SCC analysis on it.
-
- if (Tracker.Uses.empty()) {
- // If it's trivially not captured, mark it nocapture now.
- AttributeSet In =
- F->getAttributes().getParamAttributes(A->getArgNo() + 1);
- AttrSets.push_back(In.addAttribute(F->getContext(), A->getArgNo() + 1,
- Attribute::NoCapture));
- } 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 (!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;
}
}
- }
-
- // Merge all attribute sets into one in a single step.
- if (!AttrSets.empty()) {
- NumNoCapture += AttrSets.size();
- AttrSets.push_back(F->getAttributes());
- F->setAttributes(AttributeSet::get(F->getContext(), AttrSets));
- Changed = true;
}
}
// made. If the definition doesn't have a 'nocapture' attribute by now, it
// captures.
- for (scc_iterator<ArgumentGraph*> I = scc_begin(&AG), E = scc_end(&AG);
- I != E; ++I) {
- std::vector<ArgumentGraphNode*> &ArgumentSCC = *I;
+ 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
+ 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]) {
- ArgumentSCC[0]->
- Definition->
- addAttr(AttributeSet::get(ArgumentSCC[0]->Definition->getContext(),
- ArgumentSCC[0]->Definition->getArgNo() + 1,
- Attribute::NoCapture));
+ Argument *A = ArgumentSCC[0]->Definition;
+ A->addAttr(AttributeSet::get(A->getContext(), A->getArgNo() + 1, B));
++NumNoCapture;
Changed = true;
}
}
bool SCCCaptured = false;
- for (std::vector<ArgumentGraphNode*>::iterator I = ArgumentSCC.begin(),
- E = ArgumentSCC.end(); I != E && !SCCCaptured; ++I) {
+ 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;
+ if (SCCCaptured)
+ continue;
- SmallPtrSet<Argument*, 8> ArgumentSCCNodes;
+ 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 (std::vector<ArgumentGraphNode*>::iterator I = ArgumentSCC.begin(),
- E = ArgumentSCC.end(); I != E; ++I) {
+ for (auto I = ArgumentSCC.begin(), E = ArgumentSCC.end(); I != E; ++I) {
ArgumentSCCNodes.insert((*I)->Definition);
}
- for (std::vector<ArgumentGraphNode*>::iterator I = ArgumentSCC.begin(),
- E = ArgumentSCC.end(); I != E && !SCCCaptured; ++I) {
+ 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) {
+ 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;
break;
}
}
- if (SCCCaptured) continue;
+ 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,
- Attribute::NoCapture));
+ 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, R;
+ B.addAttribute(ReadAttr);
+ R.addAttribute(Attribute::ReadOnly).addAttribute(Attribute::ReadNone);
+ for (unsigned i = 0, e = ArgumentSCC.size(); i != e; ++i) {
+ Argument *A = ArgumentSCC[i]->Definition;
+ // Clear out existing readonly/readnone attributes
+ A->removeAttr(AttributeSet::get(A->getContext(), A->getArgNo() + 1, R));
+ 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 {
+/// Tests whether a function is "malloc-like".
+///
+/// A function is "malloc-like" if it returns either null or a pointer that
+/// doesn't alias any other pointer visible to the caller.
+static bool isFunctionMallocLike(Function *F,
+ SmallPtrSet<Function *, 8> &SCCNodes) {
SmallSetVector<Value *, 8> FlowsToReturn;
for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I)
if (ReturnInst *Ret = dyn_cast<ReturnInst>(I->getTerminator()))
if (Instruction *RVI = dyn_cast<Instruction>(RetVal))
switch (RVI->getOpcode()) {
- // Extend the analysis by looking upwards.
- case Instruction::BitCast:
- case Instruction::GetElementPtr:
- 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;
- }
+ // 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 (Value *IncValue : PN->incoming_values())
+ FlowsToReturn.insert(IncValue);
+ continue;
+ }
- // Check whether the pointer came from an allocation.
- case Instruction::Alloca:
+ // 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;
- 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.
+ } // fall-through
+ default:
+ return false; // Did not come from an allocation.
}
if (PointerMayBeCaptured(RetVal, false, /*StoreCaptures=*/false))
return true;
}
-/// AddNoAliasAttrs - Deduce noalias attributes for the SCC.
+/// Deduce noalias attributes for the SCC.
bool FunctionAttrs::AddNoAliasAttrs(const CallGraphSCC &SCC) {
- SmallPtrSet<Function*, 8> SCCNodes;
+ 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 == 0)
- // External node - skip it;
+ if (!F || F->hasFnAttribute(Attribute::OptimizeNone))
+ // External node or node we don't want to optimize - skip it;
return false;
// Already noalias.
if (F->isDeclaration() || F->mayBeOverridden())
return false;
- // We annotate noalias return values, which are only applicable to
+ // We annotate noalias return values, which are only applicable to
// pointer types.
if (!F->getReturnType()->isPointerTy())
continue;
- if (!IsFunctionMallocLike(F, SCCNodes))
+ if (!isFunctionMallocLike(F, SCCNodes))
return false;
}
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) {
+/// Tests whether this function is known to not return null.
+///
+/// Requires that the function returns a pointer.
+///
+/// Returns true if it believes the function will not return a null, and sets
+/// \p Speculative based on whether the returned conclusion is a speculative
+/// conclusion due to SCC calls.
+static bool isReturnNonNull(Function *F, SmallPtrSet<Function *, 8> &SCCNodes,
+ const TargetLibraryInfo &TLI, bool &Speculative) {
+ assert(F->getReturnType()->isPointerTy() &&
+ "nonnull only meaningful on pointer types");
+ Speculative = false;
+
+ SmallSetVector<Value *, 8> FlowsToReturn;
+ for (BasicBlock &BB : *F)
+ if (auto *Ret = dyn_cast<ReturnInst>(BB.getTerminator()))
+ FlowsToReturn.insert(Ret->getReturnValue());
+
+ for (unsigned i = 0; i != FlowsToReturn.size(); ++i) {
+ Value *RetVal = FlowsToReturn[i];
+
+ // If this value is locally known to be non-null, we're good
+ if (isKnownNonNull(RetVal, &TLI))
+ continue;
+
+ // Otherwise, we need to look upwards since we can't make any local
+ // conclusions.
+ Instruction *RVI = dyn_cast<Instruction>(RetVal);
+ if (!RVI)
+ return false;
+ 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;
+ }
+ case Instruction::Call:
+ case Instruction::Invoke: {
+ CallSite CS(RVI);
+ Function *Callee = CS.getCalledFunction();
+ // A call to a node within the SCC is assumed to return null until
+ // proven otherwise
+ if (Callee && SCCNodes.count(Callee)) {
+ Speculative = true;
+ continue;
+ }
+ return false;
+ }
+ default:
+ return false; // Unknown source, may be null
+ };
+ llvm_unreachable("should have either continued or returned");
+ }
+
+ return true;
+}
+
+/// Deduce nonnull attributes for the SCC.
+bool FunctionAttrs::AddNonNullAttrs(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());
+
+ // Speculative that all functions in the SCC return only nonnull
+ // pointers. We may refute this as we analyze functions.
+ bool SCCReturnsNonNull = true;
+
+ bool MadeChange = false;
+
+ // Check each function in turn, determining which functions return nonnull
+ // 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 nonnull.
+ if (F->getAttributes().hasAttribute(AttributeSet::ReturnIndex,
+ Attribute::NonNull))
+ continue;
+
+ // Definitions with weak linkage may be overridden at linktime, so
+ // treat them like declarations.
+ if (F->isDeclaration() || F->mayBeOverridden())
+ return false;
+
+ // We annotate nonnull return values, which are only applicable to
+ // pointer types.
+ if (!F->getReturnType()->isPointerTy())
+ continue;
+
+ bool Speculative = false;
+ if (isReturnNonNull(F, SCCNodes, *TLI, Speculative)) {
+ if (!Speculative) {
+ // Mark the function eagerly since we may discover a function
+ // which prevents us from speculating about the entire SCC
+ DEBUG(dbgs() << "Eagerly marking " << F->getName() << " as nonnull\n");
+ F->addAttribute(AttributeSet::ReturnIndex, Attribute::NonNull);
+ ++NumNonNullReturn;
+ MadeChange = true;
+ }
+ continue;
+ }
+ // At least one function returns something which could be null, can't
+ // speculate any more.
+ SCCReturnsNonNull = false;
+ }
+
+ if (SCCReturnsNonNull) {
+ for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
+ Function *F = (*I)->getFunction();
+ if (F->getAttributes().hasAttribute(AttributeSet::ReturnIndex,
+ Attribute::NonNull) ||
+ !F->getReturnType()->isPointerTy())
+ continue;
+
+ DEBUG(dbgs() << "SCC marking " << F->getName() << " as nonnull\n");
+ F->addAttribute(AttributeSet::ReturnIndex, Attribute::NonNull);
+ ++NumNonNullReturn;
+ MadeChange = true;
+ }
+ }
+
+ return MadeChange;
+}
+
+static void setDoesNotAccessMemory(Function &F) {
+ if (!F.doesNotAccessMemory()) {
+ F.setDoesNotAccessMemory();
+ ++NumAnnotated;
+ }
+}
+
+static void setOnlyReadsMemory(Function &F) {
+ if (!F.onlyReadsMemory()) {
+ F.setOnlyReadsMemory();
+ ++NumAnnotated;
+ }
+}
+
+static void setDoesNotThrow(Function &F) {
+ if (!F.doesNotThrow()) {
+ F.setDoesNotThrow();
+ ++NumAnnotated;
+ }
+}
+
+static void setDoesNotCapture(Function &F, unsigned n) {
+ if (!F.doesNotCapture(n)) {
+ F.setDoesNotCapture(n);
+ ++NumAnnotated;
+ }
+}
+
+static void setOnlyReadsMemory(Function &F, unsigned n) {
+ if (!F.onlyReadsMemory(n)) {
+ F.setOnlyReadsMemory(n);
+ ++NumAnnotated;
+ }
+}
+
+static void setDoesNotAlias(Function &F, unsigned n) {
+ if (!F.doesNotAlias(n)) {
+ F.setDoesNotAlias(n);
+ ++NumAnnotated;
+ }
+}
+
+/// Analyze the name and prototype of the given function and set any applicable
+/// attributes.
+///
+/// Returns true if any attributes were set and false otherwise.
+static bool inferPrototypeAttributes(Function &F, const TargetLibraryInfo &TLI) {
+ if (F.hasFnAttribute(Attribute::OptimizeNone))
+ return false;
+
FunctionType *FTy = F.getFunctionType();
LibFunc::Func TheLibFunc;
- if (!(TLI->getLibFunc(F.getName(), TheLibFunc) && TLI->has(TheLibFunc)))
+ if (!(TLI.getLibFunc(F.getName(), TheLibFunc) && TLI.has(TheLibFunc)))
return false;
switch (TheLibFunc) {
break;
case LibFunc::strchr:
case LibFunc::strrchr:
- if (FTy->getNumParams() != 2 ||
- !FTy->getParamType(0)->isPointerTy() ||
+ if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isIntegerTy())
return false;
setOnlyReadsMemory(F);
setDoesNotThrow(F);
break;
- case LibFunc::strcpy:
- case LibFunc::stpcpy:
- case LibFunc::strcat:
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:
- case LibFunc::strtoull:
- if (FTy->getNumParams() < 2 ||
- !FTy->getParamType(1)->isPointerTy())
+ 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() ||
+ if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
- break;
- case LibFunc::strcmp:
- case LibFunc::strspn:
- case LibFunc::strncmp:
- case LibFunc::strcspn:
- case LibFunc::strcoll:
- case LibFunc::strcasecmp:
- case LibFunc::strncasecmp:
- if (FTy->getNumParams() < 2 ||
- !FTy->getParamType(0)->isPointerTy() ||
+ 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);
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())
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:
- case LibFunc::statvfs:
- if (FTy->getNumParams() < 2 ||
- !FTy->getParamType(0)->isPointerTy() ||
+ 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() ||
+ 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() ||
+ 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())
+ 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())
+ 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() ||
+ if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
setOnlyReadsMemory(F);
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())
+ 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())
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())
+ 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() ||
+ if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getReturnType()->isPointerTy())
return false;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
break;
case LibFunc::read:
- if (FTy->getNumParams() != 3 ||
- !FTy->getParamType(1)->isPointerTy())
+ 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::rmdir:
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())
+ 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() ||
+ 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() ||
+ 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() ||
+ if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
break;
case LibFunc::calloc:
- if (FTy->getNumParams() != 2 ||
- !FTy->getReturnType()->isPointerTy())
+ 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:
return false;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
+ setOnlyReadsMemory(F, 1);
break;
case LibFunc::fopen:
- if (FTy->getNumParams() != 2 ||
- !FTy->getReturnType()->isPointerTy() ||
+ if (FTy->getNumParams() != 2 || !FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
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() ||
+ 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:
setDoesNotCapture(F, 2);
break;
case LibFunc::fgets:
- if (FTy->getNumParams() != 3 ||
- !FTy->getParamType(0)->isPointerTy() ||
+ 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() ||
+ 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() ||
+ if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
setDoesNotThrow(F);
return false;
setDoesNotThrow(F);
setDoesNotCapture(F, 1);
+ setOnlyReadsMemory(F, 1);
break;
case LibFunc::ungetc:
if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
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() ||
+ 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, 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; these are valid pthread cancellation points.
+ // 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() ||
+ if (FTy->getNumParams() != 2 || !FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
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);
+ 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() ||
+ 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);
setDoesNotCapture(F, 1);
+ setOnlyReadsMemory(F, 1);
break;
case LibFunc::vfprintf:
case LibFunc::vsprintf:
- if (FTy->getNumParams() != 3 ||
- !FTy->getParamType(0)->isPointerTy() ||
+ 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() ||
+ 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() ||
+ 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())
setDoesNotAccessMemory(F);
break;
case LibFunc::lstat:
- if (FTy->getNumParams() != 2 ||
- !FTy->getParamType(0)->isPointerTy() ||
+ 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())
break;
case LibFunc::dunder_strdup:
case LibFunc::dunder_strndup:
- if (FTy->getNumParams() < 1 ||
- !FTy->getReturnType()->isPointerTy() ||
+ 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())
+ 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())
setDoesNotCapture(F, 2);
break;
case LibFunc::dunder_isoc99_scanf:
- if (FTy->getNumParams() < 1 ||
- !FTy->getParamType(0)->isPointerTy())
+ 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() ||
+ 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() ||
+ if (FTy->getNumParams() != 2 || !FTy->getReturnType()->isPointerTy() ||
!FTy->getParamType(0)->isPointerTy() ||
!FTy->getParamType(1)->isPointerTy())
return false;
setDoesNotAlias(F, 0);
setDoesNotCapture(F, 1);
setDoesNotCapture(F, 2);
+ setOnlyReadsMemory(F, 1);
+ setOnlyReadsMemory(F, 2);
break;
case LibFunc::fseeko64:
case LibFunc::ftello64:
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 true;
}
-/// annotateLibraryCalls - Adds attributes to well-known standard library
-/// call declarations.
+/// Adds attributes to well-known standard library call declarations.
bool FunctionAttrs::annotateLibraryCalls(const CallGraphSCC &SCC) {
bool MadeChange = false;
for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
Function *F = (*I)->getFunction();
- if (F != 0 && F->isDeclaration())
- MadeChange |= inferPrototypeAttributes(*F);
+ if (F && F->isDeclaration())
+ MadeChange |= inferPrototypeAttributes(*F, *TLI);
}
return MadeChange;
}
bool FunctionAttrs::runOnSCC(CallGraphSCC &SCC) {
- AA = &getAnalysis<AliasAnalysis>();
- TLI = &getAnalysis<TargetLibraryInfo>();
+ TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
bool Changed = annotateLibraryCalls(SCC);
Changed |= AddReadAttrs(SCC);
- Changed |= AddNoCaptureAttrs(SCC);
+ Changed |= AddArgumentAttrs(SCC);
Changed |= AddNoAliasAttrs(SCC);
+ Changed |= AddNonNullAttrs(SCC);
return Changed;
}