#include "llvm/Attributes.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Analysis/DebugInfo.h"
+#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/Utils/Local.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/CallSite.h"
+#include "llvm/Support/IRBuilder.h"
using namespace llvm;
bool llvm::InlineFunction(CallInst *CI, InlineFunctionInfo &IFI) {
CallerNode->removeCallEdgeFor(CS);
}
+/// HandleByValArgument - When inlining a call site that has a byval argument,
+/// we have to make the implicit memcpy explicit by adding it.
+static Value *HandleByValArgument(Value *Arg, Instruction *TheCall,
+ const Function *CalledFunc,
+ InlineFunctionInfo &IFI,
+ unsigned ByValAlignment) {
+ const Type *AggTy = cast<PointerType>(Arg->getType())->getElementType();
+
+ // If the called function is readonly, then it could not mutate the caller's
+ // copy of the byval'd memory. In this case, it is safe to elide the copy and
+ // temporary.
+ if (CalledFunc->onlyReadsMemory()) {
+ // If the byval argument has a specified alignment that is greater than the
+ // passed in pointer, then we either have to round up the input pointer or
+ // give up on this transformation.
+ if (ByValAlignment <= 1) // 0 = unspecified, 1 = no particular alignment.
+ return Arg;
+
+ // If the pointer is already known to be sufficiently aligned, or if we can
+ // round it up to a larger alignment, then we don't need a temporary.
+ if (getOrEnforceKnownAlignment(Arg, ByValAlignment,
+ IFI.TD) >= ByValAlignment)
+ return Arg;
+
+ // Otherwise, we have to make a memcpy to get a safe alignment. This is bad
+ // for code quality, but rarely happens and is required for correctness.
+ }
+
+ LLVMContext &Context = Arg->getContext();
+
+ const Type *VoidPtrTy = Type::getInt8PtrTy(Context);
+
+ // Create the alloca. If we have TargetData, use nice alignment.
+ unsigned Align = 1;
+ if (IFI.TD)
+ Align = IFI.TD->getPrefTypeAlignment(AggTy);
+
+ // If the byval had an alignment specified, we *must* use at least that
+ // alignment, as it is required by the byval argument (and uses of the
+ // pointer inside the callee).
+ Align = std::max(Align, ByValAlignment);
+
+ Function *Caller = TheCall->getParent()->getParent();
+
+ Value *NewAlloca = new AllocaInst(AggTy, 0, Align, Arg->getName(),
+ &*Caller->begin()->begin());
+ // Emit a memcpy.
+ const Type *Tys[3] = {VoidPtrTy, VoidPtrTy, Type::getInt64Ty(Context)};
+ Function *MemCpyFn = Intrinsic::getDeclaration(Caller->getParent(),
+ Intrinsic::memcpy,
+ Tys, 3);
+ Value *DestCast = new BitCastInst(NewAlloca, VoidPtrTy, "tmp", TheCall);
+ Value *SrcCast = new BitCastInst(Arg, VoidPtrTy, "tmp", TheCall);
+
+ Value *Size;
+ if (IFI.TD == 0)
+ Size = ConstantExpr::getSizeOf(AggTy);
+ else
+ Size = ConstantInt::get(Type::getInt64Ty(Context),
+ IFI.TD->getTypeStoreSize(AggTy));
+
+ // Always generate a memcpy of alignment 1 here because we don't know
+ // the alignment of the src pointer. Other optimizations can infer
+ // better alignment.
+ Value *CallArgs[] = {
+ DestCast, SrcCast, Size,
+ ConstantInt::get(Type::getInt32Ty(Context), 1),
+ ConstantInt::getFalse(Context) // isVolatile
+ };
+ CallInst *TheMemCpy =
+ CallInst::Create(MemCpyFn, CallArgs, CallArgs+5, "", TheCall);
+
+ // If we have a call graph, update it.
+ if (CallGraph *CG = IFI.CG) {
+ CallGraphNode *MemCpyCGN = CG->getOrInsertFunction(MemCpyFn);
+ CallGraphNode *CallerNode = (*CG)[Caller];
+ CallerNode->addCalledFunction(TheMemCpy, MemCpyCGN);
+ }
+
+ // Uses of the argument in the function should use our new alloca
+ // instead.
+ return NewAlloca;
+}
+
+// isUsedByLifetimeMarker - Check whether this Value is used by a lifetime
+// intrinsic.
+static bool isUsedByLifetimeMarker(Value *V) {
+ for (Value::use_iterator UI = V->use_begin(), UE = V->use_end(); UI != UE;
+ ++UI) {
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*UI)) {
+ switch (II->getIntrinsicID()) {
+ default: break;
+ case Intrinsic::lifetime_start:
+ case Intrinsic::lifetime_end:
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
+// hasLifetimeMarkers - Check whether the given alloca already has
+// lifetime.start or lifetime.end intrinsics.
+static bool hasLifetimeMarkers(AllocaInst *AI) {
+ const Type *Int8PtrTy = Type::getInt8PtrTy(AI->getType()->getContext());
+ if (AI->getType() == Int8PtrTy)
+ return isUsedByLifetimeMarker(AI);
+
+ // Do a scan to find all the bitcasts to i8*.
+ for (Value::use_iterator I = AI->use_begin(), E = AI->use_end(); I != E;
+ ++I) {
+ if (I->getType() != Int8PtrTy) continue;
+ if (!isa<BitCastInst>(*I)) continue;
+ if (isUsedByLifetimeMarker(*I))
+ return true;
+ }
+ return false;
+}
+
// InlineFunction - This function inlines the called function into the basic
// block of the caller. This returns false if it is not possible to inline this
// call. The program is still in a well defined state if this occurs though.
//
// Note that this only does one level of inlining. For example, if the
// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
-// exists in the instruction stream. Similiarly this will inline a recursive
+// exists in the instruction stream. Similarly this will inline a recursive
// function by one level.
//
bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI) {
CalledFunc->isDeclaration() || // call, or call to a vararg function!
CalledFunc->getFunctionType()->isVarArg()) return false;
-
// If the call to the callee is not a tail call, we must clear the 'tail'
// flags on any calls that we inline.
bool MustClearTailCallFlags =
// by them explicit. However, we don't do this if the callee is readonly
// or readnone, because the copy would be unneeded: the callee doesn't
// modify the struct.
- if (CalledFunc->paramHasAttr(ArgNo+1, Attribute::ByVal) &&
- !CalledFunc->onlyReadsMemory()) {
- const Type *AggTy = cast<PointerType>(I->getType())->getElementType();
- const Type *VoidPtrTy =
- Type::getInt8PtrTy(Context);
-
- // Create the alloca. If we have TargetData, use nice alignment.
- unsigned Align = 1;
- if (IFI.TD) Align = IFI.TD->getPrefTypeAlignment(AggTy);
- Value *NewAlloca = new AllocaInst(AggTy, 0, Align,
- I->getName(),
- &*Caller->begin()->begin());
- // Emit a memcpy.
- const Type *Tys[3] = {VoidPtrTy, VoidPtrTy, Type::getInt64Ty(Context)};
- Function *MemCpyFn = Intrinsic::getDeclaration(Caller->getParent(),
- Intrinsic::memcpy,
- Tys, 3);
- Value *DestCast = new BitCastInst(NewAlloca, VoidPtrTy, "tmp", TheCall);
- Value *SrcCast = new BitCastInst(*AI, VoidPtrTy, "tmp", TheCall);
-
- Value *Size;
- if (IFI.TD == 0)
- Size = ConstantExpr::getSizeOf(AggTy);
- else
- Size = ConstantInt::get(Type::getInt64Ty(Context),
- IFI.TD->getTypeStoreSize(AggTy));
-
- // Always generate a memcpy of alignment 1 here because we don't know
- // the alignment of the src pointer. Other optimizations can infer
- // better alignment.
- Value *CallArgs[] = {
- DestCast, SrcCast, Size,
- ConstantInt::get(Type::getInt32Ty(Context), 1),
- ConstantInt::get(Type::getInt1Ty(Context), 0)
- };
- CallInst *TheMemCpy =
- CallInst::Create(MemCpyFn, CallArgs, CallArgs+5, "", TheCall);
-
- // If we have a call graph, update it.
- if (CallGraph *CG = IFI.CG) {
- CallGraphNode *MemCpyCGN = CG->getOrInsertFunction(MemCpyFn);
- CallGraphNode *CallerNode = (*CG)[Caller];
- CallerNode->addCalledFunction(TheMemCpy, MemCpyCGN);
- }
-
- // Uses of the argument in the function should use our new alloca
- // instead.
- ActualArg = NewAlloca;
-
+ if (CalledFunc->paramHasAttr(ArgNo+1, Attribute::ByVal)) {
+ ActualArg = HandleByValArgument(ActualArg, TheCall, CalledFunc, IFI,
+ CalledFunc->getParamAlignment(ArgNo+1));
+
// Calls that we inline may use the new alloca, so we need to clear
- // their 'tail' flags.
- MustClearTailCallFlags = true;
+ // their 'tail' flags if HandleByValArgument introduced a new alloca and
+ // the callee has calls.
+ MustClearTailCallFlags |= ActualArg != *AI;
}
VMap[I] = ActualArg;
if (!isa<Constant>(AI->getArraySize()))
continue;
- // Keep track of the static allocas that we inline into the caller if the
- // StaticAllocas pointer is non-null.
+ // Keep track of the static allocas that we inline into the caller.
IFI.StaticAllocas.push_back(AI);
// Scan for the block of allocas that we can move over, and move them
}
}
+ // Leave lifetime markers for the static alloca's, scoping them to the
+ // function we just inlined.
+ if (!IFI.StaticAllocas.empty()) {
+ // Also preserve the call graph, if applicable.
+ CallGraphNode *StartCGN = 0, *EndCGN = 0, *CallerNode = 0;
+ if (CallGraph *CG = IFI.CG) {
+ Function *Start = Intrinsic::getDeclaration(Caller->getParent(),
+ Intrinsic::lifetime_start);
+ Function *End = Intrinsic::getDeclaration(Caller->getParent(),
+ Intrinsic::lifetime_end);
+ StartCGN = CG->getOrInsertFunction(Start);
+ EndCGN = CG->getOrInsertFunction(End);
+ CallerNode = (*CG)[Caller];
+ }
+
+ IRBuilder<> builder(FirstNewBlock->begin());
+ for (unsigned ai = 0, ae = IFI.StaticAllocas.size(); ai != ae; ++ai) {
+ AllocaInst *AI = IFI.StaticAllocas[ai];
+
+ // If the alloca is already scoped to something smaller than the whole
+ // function then there's no need to add redundant, less accurate markers.
+ if (hasLifetimeMarkers(AI))
+ continue;
+
+ CallInst *StartCall = builder.CreateLifetimeStart(AI);
+ if (IFI.CG) CallerNode->addCalledFunction(StartCall, StartCGN);
+ for (unsigned ri = 0, re = Returns.size(); ri != re; ++ri) {
+ IRBuilder<> builder(Returns[ri]);
+ CallInst *EndCall = builder.CreateLifetimeEnd(AI);
+ if (IFI.CG) CallerNode->addCalledFunction(EndCall, EndCGN);
+ }
+ }
+ }
+
// If the inlined code contained dynamic alloca instructions, wrap the inlined
// code with llvm.stacksave/llvm.stackrestore intrinsics.
if (InlinedFunctionInfo.ContainsDynamicAllocas) {
// any users of the original call/invoke instruction.
const Type *RTy = CalledFunc->getReturnType();
+ PHINode *PHI = 0;
if (Returns.size() > 1) {
// The PHI node should go at the front of the new basic block to merge all
// possible incoming values.
- PHINode *PHI = 0;
if (!TheCall->use_empty()) {
- PHI = PHINode::Create(RTy, TheCall->getName(),
+ PHI = PHINode::Create(RTy, Returns.size(), TheCall->getName(),
AfterCallBB->begin());
// Anything that used the result of the function call should now use the
// PHI node as their operand.
"Ret value not consistent in function!");
PHI->addIncoming(RI->getReturnValue(), RI->getParent());
}
-
- // Now that we inserted the PHI, check to see if it has a single value
- // (e.g. all the entries are the same or undef). If so, remove the PHI so
- // it doesn't block other optimizations.
- if (Value *V = PHI->hasConstantValue()) {
- PHI->replaceAllUsesWith(V);
- PHI->eraseFromParent();
- }
}
// Now we can remove the CalleeEntry block, which is now empty.
Caller->getBasicBlockList().erase(CalleeEntry);
+ // If we inserted a phi node, check to see if it has a single value (e.g. all
+ // the entries are the same or undef). If so, remove the PHI so it doesn't
+ // block other optimizations.
+ if (PHI)
+ if (Value *V = SimplifyInstruction(PHI, IFI.TD)) {
+ PHI->replaceAllUsesWith(V);
+ PHI->eraseFromParent();
+ }
+
return true;
}
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