projects/ldc: gen/passes/SimplifyDRuntimeCalls.cpp comparison

comparison gen/passes/SimplifyDRuntimeCalls.cpp @ 1650:40bd4a0d4870

Update to work with LLVM 2.7. Removed use of dyn_cast, llvm no compiles without exceptions and rtti by default. We do need exceptions for the libconfig stuff, but rtti isn't necessary (anymore). Debug info needs to be rewritten, as in LLVM 2.7 the format has completely changed. To have something to look at while rewriting, the old code has been wrapped inside #ifndef DISABLE_DEBUG_INFO , this means that you have to define this to compile at the moment. Updated tango 0.99.9 patch to include updated EH runtime code, which is needed for LLVM 2.7 as well.

author	Tomas Lindquist Olsen
date	Wed, 19 May 2010 12:42:32 +0200
parents	8d086d552909
children

comparison

equal deleted inserted replaced

-:36da40ecbbe0
+:40bd4a0d4870
 #define DEBUG_TYPE "simplify-drtcalls"
 #include "Passes.h"
+#include "llvm/Function.h"
 #include "llvm/Pass.h"
 #include "llvm/Intrinsics.h"
 #include "llvm/Support/IRBuilder.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/ValueTracking.h"
 Function *Caller;
 bool* Changed;
 const TargetData *TD;
 AliasAnalysis *AA;
 LLVMContext *Context;
 /// CastToCStr - Return V if it is an i8*, otherwise cast it to i8*.
 Value *CastToCStr(Value *V, IRBuilder<> &B);
 /// EmitMemCpy - Emit a call to the memcpy function to the builder.  This
 /// always expects that the size has type 'intptr_t' and Dst/Src are pointers.
 Value *EmitMemCpy(Value *Dst, Value *Src, Value *Len,
 unsigned Align, IRBuilder<> &B);
 public:
 LibCallOptimization() { }
 virtual ~LibCallOptimization() {}
 /// CallOptimizer - This pure virtual method is implemented by base classes to
 /// do various optimizations.  If this returns null then no transformation was
 /// performed.  If it returns CI, then it transformed the call and CI is to be
 /// deleted.  If it returns something else, replace CI with the new value and
 /// delete CI.
 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B)=0;
 Value *OptimizeCall(CallInst *CI, bool& Changed, const TargetData &TD,
 AliasAnalysis& AA, IRBuilder<> &B) {
 Caller = CI->getParent()->getParent();
 this->Changed = &Changed;
 this->TD = &TD;
 if (Callee->arg_size() != 4 || !isa<PointerType>(FT->getReturnType()) ||
 !isa<IntegerType>(FT->getParamType(1)) ||
 FT->getParamType(1) != FT->getParamType(2) ||
 FT->getParamType(3) != FT->getReturnType())
 return 0;
 // Whether or not this allocates is irrelevant if the result isn't used.
 // Just delete if that's the case.
 if (CI->use_empty())
 return CI;
 Value* NewLen = CI->getOperand(2);
 if (Constant* NewCst = dyn_cast<Constant>(NewLen)) {
 Value* Data = CI->getOperand(4);
 // For now, we just catch the simplest of cases.
 //
 // TODO: Implement a more general way to compare old and new
 //       lengths, to catch cases like "arr.length = arr.length - 1;"
 //       (But beware of unsigned overflow! For example, we can't
 //       safely transform that example if arr.length may be 0)
 // Setting length to 0 never reallocates, so replace by data argument
 if (NewCst->isNullValue())
 return Data;
 // If both lengths are constant integers, see if NewLen <= OldLen
 Value* OldLen = CI->getOperand(3);
 if (ConstantInt* OldInt = dyn_cast<ConstantInt>(OldLen))
 if (ConstantInt* NewInt = dyn_cast<ConstantInt>(NewCst))
 if (NewInt->getValue().ule(OldInt->getValue()))
 const FunctionType *FT = Callee->getFunctionType();
 const Type* RetTy = FT->getReturnType();
 if (Callee->arg_size() != 3 || !isa<IntegerType>(RetTy) ||
 FT->getParamType(1) != RetTy || FT->getParamType(2) != RetTy)
 return 0;
 Value* OldLen = CI->getOperand(1);
 Value* OldSize = CI->getOperand(2);
 Value* NewSize = CI->getOperand(3);
 // If the old length was zero, always return zero.
 if (Constant* LenCst = dyn_cast<Constant>(OldLen))
 if (LenCst->isNullValue())
 return OldLen;
 // Equal sizes are much faster to check for, so do so now.
 if (OldSize == NewSize)
 return OldLen;
 // If both sizes are constant integers, see if OldSize is a multiple of NewSize
 if (ConstantInt* OldInt = dyn_cast<ConstantInt>(OldSize))
 if (ConstantInt* NewInt = dyn_cast<ConstantInt>(NewSize)) {
 // Don't crash on NewSize == 0, even though it shouldn't happen.
 if (NewInt->isNullValue())
 return 0;
 APInt Quot, Rem;
 APInt::udivrem(OldInt->getValue(), NewInt->getValue(), Quot, Rem);
 if (Rem == 0)
 return B.CreateMul(OldLen, ConstantInt::get(*Context, Quot));
 }
 // Allocations are never equal to constants, so remove any equality
 // comparisons to constants. (Most importantly comparisons to null at
 // the start of inlined member functions)
 for (CallInst::use_iterator I = CI->use_begin(), E = CI->use_end() ; I != E;) {
 Instruction* User = cast<Instruction>(*I++);
 if (ICmpInst* Cmp = dyn_cast<ICmpInst>(User)) {
 if (!Cmp->isEquality())
 continue;
 Constant* C = 0;
 if ((C = dyn_cast<Constant>(Cmp->getOperand(0)))
 Cmp->setOperand(1, C);
 *Changed = true;
 }
 }
 }
 // If it's not used (anymore), pre-emptively GC it.
 if (CI->use_empty())
 return CI;
 return 0;
 }
 FT->getParamType(0) != VoidPtrTy ||
 !isa<IntegerType>(FT->getParamType(1)) ||
 FT->getParamType(2) != VoidPtrTy ||
 FT->getParamType(3) != FT->getParamType(1))
 return 0;
 Value* Size = CI->getOperand(2);
 // Check the lengths match
 if (CI->getOperand(4) != Size)
 return 0;
 // Assume unknown size unless we have constant size (that fits in an uint)
 unsigned Sz = ~0U;
 if (ConstantInt* Int = dyn_cast<ConstantInt>(Size))
 if (Int->getValue().isIntN(32))
 Sz = Int->getValue().getZExtValue();
 // Check if the pointers may alias
 if (AA->alias(CI->getOperand(1), Sz, CI->getOperand(3), Sz))
 return 0;
 // Equal length and the pointers definitely don't alias, so it's safe to
 // replace the call with memcpy
 return EmitMemCpy(CI->getOperand(1), CI->getOperand(3), Size, 0, B);
 }
 };
 namespace {
 /// This pass optimizes library functions from the D runtime as used by LDC.
 ///
 class VISIBILITY_HIDDEN SimplifyDRuntimeCalls : public FunctionPass {
 StringMap<LibCallOptimization*> Optimizations;
 // Array operations
 ArraySetLengthOpt ArraySetLength;
 ArrayCastLenOpt ArrayCastLen;
 ArraySliceCopyOpt ArraySliceCopy;
 // GC allocations
 AllocationOpt Allocation;
 public:
 static char ID; // Pass identification
 SimplifyDRuntimeCalls() : FunctionPass(&ID) {}
 void InitOptimizations();
 bool runOnFunction(Function &F);
 bool runOnce(Function &F, const TargetData& TD, AliasAnalysis& AA);
 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
 AU.addRequired<TargetData>();
 AU.addRequired<AliasAnalysis>();
 }
 };
 static RegisterPass<SimplifyDRuntimeCalls>
 X("simplify-drtcalls", "Simplify calls to D runtime");
 // Public interface to the pass.
 FunctionPass *createSimplifyDRuntimeCalls() {
 return new SimplifyDRuntimeCalls();
 }
 /// Optimizations - Populate the Optimizations map with all the optimizations
 /// we know.
 void SimplifyDRuntimeCalls::InitOptimizations() {
 // Some array-related optimizations
 Optimizations["_d_arraysetlengthT"] = &ArraySetLength;
 Optimizations["_d_arraysetlengthiT"] = &ArraySetLength;
 Optimizations["_d_array_cast_len"] = &ArrayCastLen;
 Optimizations["_d_array_slice_copy"] = &ArraySliceCopy;
 /* Delete calls to runtime functions which aren't needed if their result is
 * unused. That comes down to functions that don't do anything but
 * GC-allocate and initialize some memory.
 * We don't need to do this for functions which are marked 'readnone' or
 * 'readonly', since LLVM doesn't need our help figuring out when those can
 /// runOnFunction - Top level algorithm.
 ///
 bool SimplifyDRuntimeCalls::runOnFunction(Function &F) {
 if (Optimizations.empty())
 InitOptimizations();
 const TargetData &TD = getAnalysis<TargetData>();
 AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
 // Iterate to catch opportunities opened up by other optimizations,
 // such as calls that are only used as arguments to unused calls:
 // When the second call gets deleted the first call will become unused, but
 // without iteration we wouldn't notice if we inspected the first call
 // before the second one.
 bool Changed;
 do {
 Changed = runOnce(F, TD, AA);
 EverChanged |= Changed;
 } while (Changed);
 return EverChanged;
 }
 bool SimplifyDRuntimeCalls::runOnce(Function &F, const TargetData& TD, AliasAnalysis& AA) {
 IRBuilder<> Builder(F.getContext());
 for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
 // Ignore non-calls.
 CallInst *CI = dyn_cast<CallInst>(I++);
 if (!CI) continue;
 // Ignore indirect calls and calls to non-external functions.
 Function *Callee = CI->getCalledFunction();
 if (Callee == 0 || !Callee->isDeclaration() ||
 !(Callee->hasExternalLinkage() || Callee->hasDLLImportLinkage()))
 continue;
 // Ignore unknown calls.
 StringMap<LibCallOptimization*>::iterator OMI =
 Optimizations.find(Callee->getName());
 if (OMI == Optimizations.end()) continue;
 DEBUG(errs() << "SimplifyDRuntimeCalls inspecting: " << *CI);
 // Set the builder to the instruction after the call.
 Builder.SetInsertPoint(BB, I);
 // Try to optimize this call.
 Value *Result = OMI->second->OptimizeCall(CI, Changed, TD, AA, Builder);
 if (Result == 0) continue;
 DEBUG(errs() << "SimplifyDRuntimeCalls simplified: " << *CI;
 errs() << "  into: " << *Result << "\n");
 // Something changed!
 Changed = true;
 if (Result == CI) {
 assert(CI->use_empty());
 ++NumDeleted;
 AA.deleteValue(CI);
 } else {
 ++NumSimplified;
 AA.replaceWithNewValue(CI, Result);
 if (!CI->use_empty())
 CI->replaceAllUsesWith(Result);
 if (!Result->hasName())
 Result->takeName(CI);
 }
 // Inspect the instruction after the call (which was potentially just
 // added) next.
 I = CI; ++I;
 CI->eraseFromParent();
 }
 }
 return Changed;
 }

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comparison gen/passes/SimplifyDRuntimeCalls.cpp @ 1650:40bd4a0d4870