mirror of
https://github.com/c64scene-ar/llvm-6502.git
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077707ccc0
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52295 91177308-0d34-0410-b5e6-96231b3b80d8
1526 lines
57 KiB
C++
1526 lines
57 KiB
C++
//===- SimplifyLibCalls.cpp - Optimize specific well-known library calls --===//
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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 pass that applies a variety of small
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// optimizations for calls to specific well-known function calls (e.g. runtime
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// library functions). For example, a call to the function "exit(3)" that
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// occurs within the main() function can be transformed into a simple "return 3"
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// instruction. Any optimization that takes this form (replace call to library
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// function with simpler code that provides the same result) belongs in this
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// file.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "simplify-libcalls"
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/Intrinsics.h"
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#include "llvm/Module.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/IRBuilder.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/StringMap.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Config/config.h"
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using namespace llvm;
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STATISTIC(NumSimplified, "Number of library calls simplified");
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//===----------------------------------------------------------------------===//
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// Optimizer Base Class
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//===----------------------------------------------------------------------===//
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/// This class is the abstract base class for the set of optimizations that
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/// corresponds to one library call.
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namespace {
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class VISIBILITY_HIDDEN LibCallOptimization {
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protected:
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Function *Caller;
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const TargetData *TD;
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public:
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LibCallOptimization() { }
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virtual ~LibCallOptimization() {}
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/// CallOptimizer - This pure virtual method is implemented by base classes to
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/// do various optimizations. If this returns null then no transformation was
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/// performed. If it returns CI, then it transformed the call and CI is to be
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/// deleted. If it returns something else, replace CI with the new value and
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/// delete CI.
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virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) =0;
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Value *OptimizeCall(CallInst *CI, const TargetData &TD, IRBuilder &B) {
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Caller = CI->getParent()->getParent();
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this->TD = &TD;
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return CallOptimizer(CI->getCalledFunction(), CI, B);
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}
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/// CastToCStr - Return V if it is an i8*, otherwise cast it to i8*.
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Value *CastToCStr(Value *V, IRBuilder &B);
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/// EmitStrLen - Emit a call to the strlen function to the builder, for the
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/// specified pointer. Ptr is required to be some pointer type, and the
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/// return value has 'intptr_t' type.
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Value *EmitStrLen(Value *Ptr, IRBuilder &B);
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/// EmitMemCpy - Emit a call to the memcpy function to the builder. This
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/// always expects that the size has type 'intptr_t' and Dst/Src are pointers.
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Value *EmitMemCpy(Value *Dst, Value *Src, Value *Len,
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unsigned Align, IRBuilder &B);
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/// EmitMemChr - Emit a call to the memchr function. This assumes that Ptr is
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/// a pointer, Val is an i32 value, and Len is an 'intptr_t' value.
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Value *EmitMemChr(Value *Ptr, Value *Val, Value *Len, IRBuilder &B);
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/// EmitUnaryFloatFnCall - Emit a call to the unary function named 'Name' (e.g.
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/// 'floor'). This function is known to take a single of type matching 'Op'
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/// and returns one value with the same type. If 'Op' is a long double, 'l'
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/// is added as the suffix of name, if 'Op' is a float, we add a 'f' suffix.
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Value *EmitUnaryFloatFnCall(Value *Op, const char *Name, IRBuilder &B);
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/// EmitPutChar - Emit a call to the putchar function. This assumes that Char
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/// is an integer.
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void EmitPutChar(Value *Char, IRBuilder &B);
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/// EmitPutS - Emit a call to the puts function. This assumes that Str is
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/// some pointer.
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void EmitPutS(Value *Str, IRBuilder &B);
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/// EmitFPutC - Emit a call to the fputc function. This assumes that Char is
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/// an i32, and File is a pointer to FILE.
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void EmitFPutC(Value *Char, Value *File, IRBuilder &B);
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/// EmitFPutS - Emit a call to the puts function. Str is required to be a
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/// pointer and File is a pointer to FILE.
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void EmitFPutS(Value *Str, Value *File, IRBuilder &B);
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/// EmitFWrite - Emit a call to the fwrite function. This assumes that Ptr is
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/// a pointer, Size is an 'intptr_t', and File is a pointer to FILE.
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void EmitFWrite(Value *Ptr, Value *Size, Value *File, IRBuilder &B);
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};
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} // End anonymous namespace.
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/// CastToCStr - Return V if it is an i8*, otherwise cast it to i8*.
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Value *LibCallOptimization::CastToCStr(Value *V, IRBuilder &B) {
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return B.CreateBitCast(V, PointerType::getUnqual(Type::Int8Ty), "cstr");
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}
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/// EmitStrLen - Emit a call to the strlen function to the builder, for the
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/// specified pointer. This always returns an integer value of size intptr_t.
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Value *LibCallOptimization::EmitStrLen(Value *Ptr, IRBuilder &B) {
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Module *M = Caller->getParent();
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Constant *StrLen =M->getOrInsertFunction("strlen", TD->getIntPtrType(),
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PointerType::getUnqual(Type::Int8Ty),
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NULL);
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return B.CreateCall(StrLen, CastToCStr(Ptr, B), "strlen");
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}
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/// EmitMemCpy - Emit a call to the memcpy function to the builder. This always
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/// expects that the size has type 'intptr_t' and Dst/Src are pointers.
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Value *LibCallOptimization::EmitMemCpy(Value *Dst, Value *Src, Value *Len,
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unsigned Align, IRBuilder &B) {
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Module *M = Caller->getParent();
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Intrinsic::ID IID = Len->getType() == Type::Int32Ty ?
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Intrinsic::memcpy_i32 : Intrinsic::memcpy_i64;
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Value *MemCpy = Intrinsic::getDeclaration(M, IID);
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return B.CreateCall4(MemCpy, CastToCStr(Dst, B), CastToCStr(Src, B), Len,
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ConstantInt::get(Type::Int32Ty, Align));
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}
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/// EmitMemChr - Emit a call to the memchr function. This assumes that Ptr is
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/// a pointer, Val is an i32 value, and Len is an 'intptr_t' value.
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Value *LibCallOptimization::EmitMemChr(Value *Ptr, Value *Val,
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Value *Len, IRBuilder &B) {
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Module *M = Caller->getParent();
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Value *MemChr = M->getOrInsertFunction("memchr",
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PointerType::getUnqual(Type::Int8Ty),
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PointerType::getUnqual(Type::Int8Ty),
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Type::Int32Ty, TD->getIntPtrType(),
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NULL);
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return B.CreateCall3(MemChr, CastToCStr(Ptr, B), Val, Len, "memchr");
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}
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/// EmitUnaryFloatFnCall - Emit a call to the unary function named 'Name' (e.g.
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/// 'floor'). This function is known to take a single of type matching 'Op' and
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/// returns one value with the same type. If 'Op' is a long double, 'l' is
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/// added as the suffix of name, if 'Op' is a float, we add a 'f' suffix.
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Value *LibCallOptimization::EmitUnaryFloatFnCall(Value *Op, const char *Name,
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IRBuilder &B) {
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char NameBuffer[20];
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if (Op->getType() != Type::DoubleTy) {
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// If we need to add a suffix, copy into NameBuffer.
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unsigned NameLen = strlen(Name);
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assert(NameLen < sizeof(NameBuffer)-2);
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memcpy(NameBuffer, Name, NameLen);
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if (Op->getType() == Type::FloatTy)
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NameBuffer[NameLen] = 'f'; // floorf
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else
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NameBuffer[NameLen] = 'l'; // floorl
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NameBuffer[NameLen+1] = 0;
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Name = NameBuffer;
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}
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Module *M = Caller->getParent();
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Value *Callee = M->getOrInsertFunction(Name, Op->getType(),
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Op->getType(), NULL);
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return B.CreateCall(Callee, Op, Name);
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}
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/// EmitPutChar - Emit a call to the putchar function. This assumes that Char
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/// is an integer.
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void LibCallOptimization::EmitPutChar(Value *Char, IRBuilder &B) {
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Module *M = Caller->getParent();
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Value *F = M->getOrInsertFunction("putchar", Type::Int32Ty,
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Type::Int32Ty, NULL);
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B.CreateCall(F, B.CreateIntCast(Char, Type::Int32Ty, "chari"), "putchar");
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}
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/// EmitPutS - Emit a call to the puts function. This assumes that Str is
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/// some pointer.
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void LibCallOptimization::EmitPutS(Value *Str, IRBuilder &B) {
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Module *M = Caller->getParent();
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Value *F = M->getOrInsertFunction("puts", Type::Int32Ty,
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PointerType::getUnqual(Type::Int8Ty), NULL);
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B.CreateCall(F, CastToCStr(Str, B), "puts");
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}
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/// EmitFPutC - Emit a call to the fputc function. This assumes that Char is
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/// an integer and File is a pointer to FILE.
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void LibCallOptimization::EmitFPutC(Value *Char, Value *File, IRBuilder &B) {
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Module *M = Caller->getParent();
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Constant *F = M->getOrInsertFunction("fputc", Type::Int32Ty, Type::Int32Ty,
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File->getType(), NULL);
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Char = B.CreateIntCast(Char, Type::Int32Ty, "chari");
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B.CreateCall2(F, Char, File, "fputc");
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}
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/// EmitFPutS - Emit a call to the puts function. Str is required to be a
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/// pointer and File is a pointer to FILE.
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void LibCallOptimization::EmitFPutS(Value *Str, Value *File, IRBuilder &B) {
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Module *M = Caller->getParent();
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Constant *F = M->getOrInsertFunction("fputs", Type::Int32Ty,
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PointerType::getUnqual(Type::Int8Ty),
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File->getType(), NULL);
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B.CreateCall2(F, CastToCStr(Str, B), File, "fputs");
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}
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/// EmitFWrite - Emit a call to the fwrite function. This assumes that Ptr is
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/// a pointer, Size is an 'intptr_t', and File is a pointer to FILE.
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void LibCallOptimization::EmitFWrite(Value *Ptr, Value *Size, Value *File,
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IRBuilder &B) {
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Module *M = Caller->getParent();
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Constant *F = M->getOrInsertFunction("fwrite", TD->getIntPtrType(),
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PointerType::getUnqual(Type::Int8Ty),
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TD->getIntPtrType(), TD->getIntPtrType(),
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File->getType(), NULL);
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B.CreateCall4(F, CastToCStr(Ptr, B), Size,
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ConstantInt::get(TD->getIntPtrType(), 1), File);
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}
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//===----------------------------------------------------------------------===//
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// Helper Functions
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//===----------------------------------------------------------------------===//
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/// GetConstantStringInfo - This function computes the length of a
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/// null-terminated C string pointed to by V. If successful, it returns true
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/// and returns the string in Str. If unsuccessful, it returns false.
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static bool GetConstantStringInfo(Value *V, std::string &Str) {
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// Look bitcast instructions.
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if (BitCastInst *BCI = dyn_cast<BitCastInst>(V))
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return GetConstantStringInfo(BCI->getOperand(0), Str);
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// If the value is not a GEP instruction nor a constant expression with a
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// GEP instruction, then return false because ConstantArray can't occur
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// any other way
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User *GEP = 0;
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if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
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GEP = GEPI;
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} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
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if (CE->getOpcode() != Instruction::GetElementPtr)
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return false;
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GEP = CE;
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} else {
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return false;
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}
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// Make sure the GEP has exactly three arguments.
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if (GEP->getNumOperands() != 3)
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return false;
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// Check to make sure that the first operand of the GEP is an integer and
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// has value 0 so that we are sure we're indexing into the initializer.
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if (ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(1))) {
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if (!Idx->isZero())
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return false;
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} else
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return false;
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// If the second index isn't a ConstantInt, then this is a variable index
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// into the array. If this occurs, we can't say anything meaningful about
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// the string.
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uint64_t StartIdx = 0;
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if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
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StartIdx = CI->getZExtValue();
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else
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return false;
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// The GEP instruction, constant or instruction, must reference a global
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// variable that is a constant and is initialized. The referenced constant
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// initializer is the array that we'll use for optimization.
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GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
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if (!GV || !GV->isConstant() || !GV->hasInitializer())
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return false;
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Constant *GlobalInit = GV->getInitializer();
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// Handle the ConstantAggregateZero case
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if (isa<ConstantAggregateZero>(GlobalInit)) {
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// This is a degenerate case. The initializer is constant zero so the
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// length of the string must be zero.
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Str.clear();
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return true;
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}
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// Must be a Constant Array
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ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
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if (Array == 0 || Array->getType()->getElementType() != Type::Int8Ty)
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return false;
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// Get the number of elements in the array
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uint64_t NumElts = Array->getType()->getNumElements();
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// Traverse the constant array from StartIdx (derived above) which is
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// the place the GEP refers to in the array.
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for (unsigned i = StartIdx; i < NumElts; ++i) {
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Constant *Elt = Array->getOperand(i);
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ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
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if (!CI) // This array isn't suitable, non-int initializer.
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return false;
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if (CI->isZero())
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return true; // we found end of string, success!
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Str += (char)CI->getZExtValue();
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}
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return false; // The array isn't null terminated.
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}
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/// GetStringLengthH - If we can compute the length of the string pointed to by
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/// the specified pointer, return 'len+1'. If we can't, return 0.
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static uint64_t GetStringLengthH(Value *V, SmallPtrSet<PHINode*, 32> &PHIs) {
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// Look through noop bitcast instructions.
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if (BitCastInst *BCI = dyn_cast<BitCastInst>(V))
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return GetStringLengthH(BCI->getOperand(0), PHIs);
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// If this is a PHI node, there are two cases: either we have already seen it
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// or we haven't.
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if (PHINode *PN = dyn_cast<PHINode>(V)) {
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if (!PHIs.insert(PN))
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return ~0ULL; // already in the set.
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// If it was new, see if all the input strings are the same length.
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uint64_t LenSoFar = ~0ULL;
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for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
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uint64_t Len = GetStringLengthH(PN->getIncomingValue(i), PHIs);
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if (Len == 0) return 0; // Unknown length -> unknown.
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if (Len == ~0ULL) continue;
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if (Len != LenSoFar && LenSoFar != ~0ULL)
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return 0; // Disagree -> unknown.
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LenSoFar = Len;
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}
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// Success, all agree.
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return LenSoFar;
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}
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// strlen(select(c,x,y)) -> strlen(x) ^ strlen(y)
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if (SelectInst *SI = dyn_cast<SelectInst>(V)) {
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uint64_t Len1 = GetStringLengthH(SI->getTrueValue(), PHIs);
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if (Len1 == 0) return 0;
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uint64_t Len2 = GetStringLengthH(SI->getFalseValue(), PHIs);
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if (Len2 == 0) return 0;
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if (Len1 == ~0ULL) return Len2;
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if (Len2 == ~0ULL) return Len1;
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if (Len1 != Len2) return 0;
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return Len1;
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}
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// If the value is not a GEP instruction nor a constant expression with a
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// GEP instruction, then return unknown.
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User *GEP = 0;
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if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
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GEP = GEPI;
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} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
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if (CE->getOpcode() != Instruction::GetElementPtr)
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return 0;
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GEP = CE;
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} else {
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return 0;
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}
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// Make sure the GEP has exactly three arguments.
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if (GEP->getNumOperands() != 3)
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return 0;
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|
|
// Check to make sure that the first operand of the GEP is an integer and
|
|
// has value 0 so that we are sure we're indexing into the initializer.
|
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if (ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(1))) {
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if (!Idx->isZero())
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return 0;
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} else
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return 0;
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// If the second index isn't a ConstantInt, then this is a variable index
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// into the array. If this occurs, we can't say anything meaningful about
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// the string.
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uint64_t StartIdx = 0;
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if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
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StartIdx = CI->getZExtValue();
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else
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return 0;
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|
// The GEP instruction, constant or instruction, must reference a global
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|
// variable that is a constant and is initialized. The referenced constant
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// initializer is the array that we'll use for optimization.
|
|
GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
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if (!GV || !GV->isConstant() || !GV->hasInitializer())
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return 0;
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Constant *GlobalInit = GV->getInitializer();
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// Handle the ConstantAggregateZero case, which is a degenerate case. The
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// initializer is constant zero so the length of the string must be zero.
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if (isa<ConstantAggregateZero>(GlobalInit))
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return 1; // Len = 0 offset by 1.
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|
// Must be a Constant Array
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|
ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
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if (!Array || Array->getType()->getElementType() != Type::Int8Ty)
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return false;
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// Get the number of elements in the array
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|
uint64_t NumElts = Array->getType()->getNumElements();
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// Traverse the constant array from StartIdx (derived above) which is
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// the place the GEP refers to in the array.
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|
for (unsigned i = StartIdx; i != NumElts; ++i) {
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Constant *Elt = Array->getOperand(i);
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ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
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if (!CI) // This array isn't suitable, non-int initializer.
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return 0;
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if (CI->isZero())
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return i-StartIdx+1; // We found end of string, success!
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}
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return 0; // The array isn't null terminated, conservatively return 'unknown'.
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}
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/// GetStringLength - If we can compute the length of the string pointed to by
|
|
/// the specified pointer, return 'len+1'. If we can't, return 0.
|
|
static uint64_t GetStringLength(Value *V) {
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|
if (!isa<PointerType>(V->getType())) return 0;
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|
|
SmallPtrSet<PHINode*, 32> PHIs;
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uint64_t Len = GetStringLengthH(V, PHIs);
|
|
// If Len is ~0ULL, we had an infinite phi cycle: this is dead code, so return
|
|
// an empty string as a length.
|
|
return Len == ~0ULL ? 1 : Len;
|
|
}
|
|
|
|
/// IsOnlyUsedInZeroEqualityComparison - Return true if it only matters that the
|
|
/// value is equal or not-equal to zero.
|
|
static bool IsOnlyUsedInZeroEqualityComparison(Value *V) {
|
|
for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
|
|
UI != E; ++UI) {
|
|
if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
|
|
if (IC->isEquality())
|
|
if (Constant *C = dyn_cast<Constant>(IC->getOperand(1)))
|
|
if (C->isNullValue())
|
|
continue;
|
|
// Unknown instruction.
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Miscellaneous LibCall Optimizations
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
namespace {
|
|
//===---------------------------------------===//
|
|
// 'exit' Optimizations
|
|
|
|
/// ExitOpt - int main() { exit(4); } --> int main() { return 4; }
|
|
struct VISIBILITY_HIDDEN ExitOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
// Verify we have a reasonable prototype for exit.
|
|
if (Callee->arg_size() == 0 || !CI->use_empty())
|
|
return 0;
|
|
|
|
// Verify the caller is main, and that the result type of main matches the
|
|
// argument type of exit.
|
|
if (!Caller->isName("main") || !Caller->hasExternalLinkage() ||
|
|
Caller->getReturnType() != CI->getOperand(1)->getType())
|
|
return 0;
|
|
|
|
TerminatorInst *OldTI = CI->getParent()->getTerminator();
|
|
|
|
// Create the return after the call.
|
|
ReturnInst *RI = B.CreateRet(CI->getOperand(1));
|
|
|
|
// Drop all successor phi node entries.
|
|
for (unsigned i = 0, e = OldTI->getNumSuccessors(); i != e; ++i)
|
|
OldTI->getSuccessor(i)->removePredecessor(CI->getParent());
|
|
|
|
// Erase all instructions from after our return instruction until the end of
|
|
// the block.
|
|
BasicBlock::iterator FirstDead = RI; ++FirstDead;
|
|
CI->getParent()->getInstList().erase(FirstDead, CI->getParent()->end());
|
|
return CI;
|
|
}
|
|
};
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// String and Memory LibCall Optimizations
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
//===---------------------------------------===//
|
|
// 'strcat' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN StrCatOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
// Verify the "strcat" function prototype.
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
if (FT->getNumParams() != 2 ||
|
|
FT->getReturnType() != PointerType::getUnqual(Type::Int8Ty) ||
|
|
FT->getParamType(0) != FT->getReturnType() ||
|
|
FT->getParamType(1) != FT->getReturnType())
|
|
return 0;
|
|
|
|
// Extract some information from the instruction
|
|
Value *Dst = CI->getOperand(1);
|
|
Value *Src = CI->getOperand(2);
|
|
|
|
// See if we can get the length of the input string.
|
|
uint64_t Len = GetStringLength(Src);
|
|
if (Len == 0) return 0;
|
|
--Len; // Unbias length.
|
|
|
|
// Handle the simple, do-nothing case: strcat(x, "") -> x
|
|
if (Len == 0)
|
|
return Dst;
|
|
|
|
// We need to find the end of the destination string. That's where the
|
|
// memory is to be moved to. We just generate a call to strlen.
|
|
Value *DstLen = EmitStrLen(Dst, B);
|
|
|
|
// Now that we have the destination's length, we must index into the
|
|
// destination's pointer to get the actual memcpy destination (end of
|
|
// the string .. we're concatenating).
|
|
Dst = B.CreateGEP(Dst, DstLen, "endptr");
|
|
|
|
// We have enough information to now generate the memcpy call to do the
|
|
// concatenation for us. Make a memcpy to copy the nul byte with align = 1.
|
|
EmitMemCpy(Dst, Src, ConstantInt::get(TD->getIntPtrType(), Len+1), 1, B);
|
|
return Dst;
|
|
}
|
|
};
|
|
|
|
//===---------------------------------------===//
|
|
// 'strchr' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN StrChrOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
// Verify the "strchr" function prototype.
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
if (FT->getNumParams() != 2 ||
|
|
FT->getReturnType() != PointerType::getUnqual(Type::Int8Ty) ||
|
|
FT->getParamType(0) != FT->getReturnType())
|
|
return 0;
|
|
|
|
Value *SrcStr = CI->getOperand(1);
|
|
|
|
// If the second operand is non-constant, see if we can compute the length
|
|
// of the input string and turn this into memchr.
|
|
ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getOperand(2));
|
|
if (CharC == 0) {
|
|
uint64_t Len = GetStringLength(SrcStr);
|
|
if (Len == 0 || FT->getParamType(1) != Type::Int32Ty) // memchr needs i32.
|
|
return 0;
|
|
|
|
return EmitMemChr(SrcStr, CI->getOperand(2), // include nul.
|
|
ConstantInt::get(TD->getIntPtrType(), Len), B);
|
|
}
|
|
|
|
// Otherwise, the character is a constant, see if the first argument is
|
|
// a string literal. If so, we can constant fold.
|
|
std::string Str;
|
|
if (!GetConstantStringInfo(SrcStr, Str))
|
|
return 0;
|
|
|
|
// strchr can find the nul character.
|
|
Str += '\0';
|
|
char CharValue = CharC->getSExtValue();
|
|
|
|
// Compute the offset.
|
|
uint64_t i = 0;
|
|
while (1) {
|
|
if (i == Str.size()) // Didn't find the char. strchr returns null.
|
|
return Constant::getNullValue(CI->getType());
|
|
// Did we find our match?
|
|
if (Str[i] == CharValue)
|
|
break;
|
|
++i;
|
|
}
|
|
|
|
// strchr(s+n,c) -> gep(s+n+i,c)
|
|
Value *Idx = ConstantInt::get(Type::Int64Ty, i);
|
|
return B.CreateGEP(SrcStr, Idx, "strchr");
|
|
}
|
|
};
|
|
|
|
//===---------------------------------------===//
|
|
// 'strcmp' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN StrCmpOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
// Verify the "strcmp" function prototype.
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
if (FT->getNumParams() != 2 || FT->getReturnType() != Type::Int32Ty ||
|
|
FT->getParamType(0) != FT->getParamType(1) ||
|
|
FT->getParamType(0) != PointerType::getUnqual(Type::Int8Ty))
|
|
return 0;
|
|
|
|
Value *Str1P = CI->getOperand(1), *Str2P = CI->getOperand(2);
|
|
if (Str1P == Str2P) // strcmp(x,x) -> 0
|
|
return ConstantInt::get(CI->getType(), 0);
|
|
|
|
std::string Str1, Str2;
|
|
bool HasStr1 = GetConstantStringInfo(Str1P, Str1);
|
|
bool HasStr2 = GetConstantStringInfo(Str2P, Str2);
|
|
|
|
if (HasStr1 && Str1.empty()) // strcmp("", x) -> *x
|
|
return B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), CI->getType());
|
|
|
|
if (HasStr2 && Str2.empty()) // strcmp(x,"") -> *x
|
|
return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
|
|
|
|
// strcmp(x, y) -> cnst (if both x and y are constant strings)
|
|
if (HasStr1 && HasStr2)
|
|
return ConstantInt::get(CI->getType(), strcmp(Str1.c_str(),Str2.c_str()));
|
|
return 0;
|
|
}
|
|
};
|
|
|
|
//===---------------------------------------===//
|
|
// 'strncmp' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN StrNCmpOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
// Verify the "strncmp" function prototype.
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
if (FT->getNumParams() != 3 || FT->getReturnType() != Type::Int32Ty ||
|
|
FT->getParamType(0) != FT->getParamType(1) ||
|
|
FT->getParamType(0) != PointerType::getUnqual(Type::Int8Ty) ||
|
|
!isa<IntegerType>(FT->getParamType(2)))
|
|
return 0;
|
|
|
|
Value *Str1P = CI->getOperand(1), *Str2P = CI->getOperand(2);
|
|
if (Str1P == Str2P) // strncmp(x,x,n) -> 0
|
|
return ConstantInt::get(CI->getType(), 0);
|
|
|
|
// Get the length argument if it is constant.
|
|
uint64_t Length;
|
|
if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getOperand(3)))
|
|
Length = LengthArg->getZExtValue();
|
|
else
|
|
return 0;
|
|
|
|
if (Length == 0) // strncmp(x,y,0) -> 0
|
|
return ConstantInt::get(CI->getType(), 0);
|
|
|
|
std::string Str1, Str2;
|
|
bool HasStr1 = GetConstantStringInfo(Str1P, Str1);
|
|
bool HasStr2 = GetConstantStringInfo(Str2P, Str2);
|
|
|
|
if (HasStr1 && Str1.empty()) // strncmp("", x, n) -> *x
|
|
return B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), CI->getType());
|
|
|
|
if (HasStr2 && Str2.empty()) // strncmp(x, "", n) -> *x
|
|
return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
|
|
|
|
// strncmp(x, y) -> cnst (if both x and y are constant strings)
|
|
if (HasStr1 && HasStr2)
|
|
return ConstantInt::get(CI->getType(),
|
|
strncmp(Str1.c_str(), Str2.c_str(), Length));
|
|
return 0;
|
|
}
|
|
};
|
|
|
|
|
|
//===---------------------------------------===//
|
|
// 'strcpy' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN StrCpyOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
// Verify the "strcpy" function prototype.
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
|
|
FT->getParamType(0) != FT->getParamType(1) ||
|
|
FT->getParamType(0) != PointerType::getUnqual(Type::Int8Ty))
|
|
return 0;
|
|
|
|
Value *Dst = CI->getOperand(1), *Src = CI->getOperand(2);
|
|
if (Dst == Src) // strcpy(x,x) -> x
|
|
return Src;
|
|
|
|
// See if we can get the length of the input string.
|
|
uint64_t Len = GetStringLength(Src);
|
|
if (Len == 0) return 0;
|
|
|
|
// We have enough information to now generate the memcpy call to do the
|
|
// concatenation for us. Make a memcpy to copy the nul byte with align = 1.
|
|
EmitMemCpy(Dst, Src, ConstantInt::get(TD->getIntPtrType(), Len), 1, B);
|
|
return Dst;
|
|
}
|
|
};
|
|
|
|
|
|
|
|
//===---------------------------------------===//
|
|
// 'strlen' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN StrLenOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
if (FT->getNumParams() != 1 ||
|
|
FT->getParamType(0) != PointerType::getUnqual(Type::Int8Ty) ||
|
|
!isa<IntegerType>(FT->getReturnType()))
|
|
return 0;
|
|
|
|
Value *Src = CI->getOperand(1);
|
|
|
|
// Constant folding: strlen("xyz") -> 3
|
|
if (uint64_t Len = GetStringLength(Src))
|
|
return ConstantInt::get(CI->getType(), Len-1);
|
|
|
|
// Handle strlen(p) != 0.
|
|
if (!IsOnlyUsedInZeroEqualityComparison(CI)) return 0;
|
|
|
|
// strlen(x) != 0 --> *x != 0
|
|
// strlen(x) == 0 --> *x == 0
|
|
return B.CreateZExt(B.CreateLoad(Src, "strlenfirst"), CI->getType());
|
|
}
|
|
};
|
|
|
|
//===---------------------------------------===//
|
|
// 'memcmp' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN MemCmpOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
if (FT->getNumParams() != 3 || !isa<PointerType>(FT->getParamType(0)) ||
|
|
!isa<PointerType>(FT->getParamType(1)) ||
|
|
FT->getReturnType() != Type::Int32Ty)
|
|
return 0;
|
|
|
|
Value *LHS = CI->getOperand(1), *RHS = CI->getOperand(2);
|
|
|
|
if (LHS == RHS) // memcmp(s,s,x) -> 0
|
|
return Constant::getNullValue(CI->getType());
|
|
|
|
// Make sure we have a constant length.
|
|
ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getOperand(3));
|
|
if (!LenC) return 0;
|
|
uint64_t Len = LenC->getZExtValue();
|
|
|
|
if (Len == 0) // memcmp(s1,s2,0) -> 0
|
|
return Constant::getNullValue(CI->getType());
|
|
|
|
if (Len == 1) { // memcmp(S1,S2,1) -> *LHS - *RHS
|
|
Value *LHSV = B.CreateLoad(CastToCStr(LHS, B), "lhsv");
|
|
Value *RHSV = B.CreateLoad(CastToCStr(RHS, B), "rhsv");
|
|
return B.CreateZExt(B.CreateSub(LHSV, RHSV, "chardiff"), CI->getType());
|
|
}
|
|
|
|
// memcmp(S1,S2,2) != 0 -> (*(short*)LHS ^ *(short*)RHS) != 0
|
|
// memcmp(S1,S2,4) != 0 -> (*(int*)LHS ^ *(int*)RHS) != 0
|
|
if ((Len == 2 || Len == 4) && IsOnlyUsedInZeroEqualityComparison(CI)) {
|
|
const Type *PTy = PointerType::getUnqual(Len == 2 ?
|
|
Type::Int16Ty : Type::Int32Ty);
|
|
LHS = B.CreateBitCast(LHS, PTy, "tmp");
|
|
RHS = B.CreateBitCast(RHS, PTy, "tmp");
|
|
LoadInst *LHSV = B.CreateLoad(LHS, "lhsv");
|
|
LoadInst *RHSV = B.CreateLoad(RHS, "rhsv");
|
|
LHSV->setAlignment(1); RHSV->setAlignment(1); // Unaligned loads.
|
|
return B.CreateZExt(B.CreateXor(LHSV, RHSV, "shortdiff"), CI->getType());
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
};
|
|
|
|
//===---------------------------------------===//
|
|
// 'memcpy' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN MemCpyOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
|
|
!isa<PointerType>(FT->getParamType(0)) ||
|
|
!isa<PointerType>(FT->getParamType(1)) ||
|
|
FT->getParamType(2) != TD->getIntPtrType())
|
|
return 0;
|
|
|
|
// memcpy(x, y, n) -> llvm.memcpy(x, y, n, 1)
|
|
EmitMemCpy(CI->getOperand(1), CI->getOperand(2), CI->getOperand(3), 1, B);
|
|
return CI->getOperand(1);
|
|
}
|
|
};
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Math Library Optimizations
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
//===---------------------------------------===//
|
|
// 'pow*' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN PowOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
// Just make sure this has 2 arguments of the same FP type, which match the
|
|
// result type.
|
|
if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
|
|
FT->getParamType(0) != FT->getParamType(1) ||
|
|
!FT->getParamType(0)->isFloatingPoint())
|
|
return 0;
|
|
|
|
Value *Op1 = CI->getOperand(1), *Op2 = CI->getOperand(2);
|
|
if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
|
|
if (Op1C->isExactlyValue(1.0)) // pow(1.0, x) -> 1.0
|
|
return Op1C;
|
|
if (Op1C->isExactlyValue(2.0)) // pow(2.0, x) -> exp2(x)
|
|
return EmitUnaryFloatFnCall(Op2, "exp2", B);
|
|
}
|
|
|
|
ConstantFP *Op2C = dyn_cast<ConstantFP>(Op2);
|
|
if (Op2C == 0) return 0;
|
|
|
|
if (Op2C->getValueAPF().isZero()) // pow(x, 0.0) -> 1.0
|
|
return ConstantFP::get(CI->getType(), 1.0);
|
|
|
|
if (Op2C->isExactlyValue(0.5)) {
|
|
// FIXME: This is not safe for -0.0 and -inf. This can only be done when
|
|
// 'unsafe' math optimizations are allowed.
|
|
// x pow(x, 0.5) sqrt(x)
|
|
// ---------------------------------------------
|
|
// -0.0 +0.0 -0.0
|
|
// -inf +inf NaN
|
|
#if 0
|
|
// pow(x, 0.5) -> sqrt(x)
|
|
return B.CreateCall(get_sqrt(), Op1, "sqrt");
|
|
#endif
|
|
}
|
|
|
|
if (Op2C->isExactlyValue(1.0)) // pow(x, 1.0) -> x
|
|
return Op1;
|
|
if (Op2C->isExactlyValue(2.0)) // pow(x, 2.0) -> x*x
|
|
return B.CreateMul(Op1, Op1, "pow2");
|
|
if (Op2C->isExactlyValue(-1.0)) // pow(x, -1.0) -> 1.0/x
|
|
return B.CreateFDiv(ConstantFP::get(CI->getType(), 1.0), Op1, "powrecip");
|
|
return 0;
|
|
}
|
|
};
|
|
|
|
//===---------------------------------------===//
|
|
// 'exp2' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN Exp2Opt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
// Just make sure this has 1 argument of FP type, which matches the
|
|
// result type.
|
|
if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
|
|
!FT->getParamType(0)->isFloatingPoint())
|
|
return 0;
|
|
|
|
Value *Op = CI->getOperand(1);
|
|
// Turn exp2(sitofp(x)) -> ldexp(1.0, sext(x)) if sizeof(x) <= 32
|
|
// Turn exp2(uitofp(x)) -> ldexp(1.0, zext(x)) if sizeof(x) < 32
|
|
Value *LdExpArg = 0;
|
|
if (SIToFPInst *OpC = dyn_cast<SIToFPInst>(Op)) {
|
|
if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() <= 32)
|
|
LdExpArg = B.CreateSExt(OpC->getOperand(0), Type::Int32Ty, "tmp");
|
|
} else if (UIToFPInst *OpC = dyn_cast<UIToFPInst>(Op)) {
|
|
if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() < 32)
|
|
LdExpArg = B.CreateZExt(OpC->getOperand(0), Type::Int32Ty, "tmp");
|
|
}
|
|
|
|
if (LdExpArg) {
|
|
const char *Name;
|
|
if (Op->getType() == Type::FloatTy)
|
|
Name = "ldexpf";
|
|
else if (Op->getType() == Type::DoubleTy)
|
|
Name = "ldexp";
|
|
else
|
|
Name = "ldexpl";
|
|
|
|
Constant *One = ConstantFP::get(APFloat(1.0f));
|
|
if (Op->getType() != Type::FloatTy)
|
|
One = ConstantExpr::getFPExtend(One, Op->getType());
|
|
|
|
Module *M = Caller->getParent();
|
|
Value *Callee = M->getOrInsertFunction(Name, Op->getType(),
|
|
Op->getType(), Type::Int32Ty,NULL);
|
|
return B.CreateCall2(Callee, One, LdExpArg);
|
|
}
|
|
return 0;
|
|
}
|
|
};
|
|
|
|
|
|
//===---------------------------------------===//
|
|
// Double -> Float Shrinking Optimizations for Unary Functions like 'floor'
|
|
|
|
struct VISIBILITY_HIDDEN UnaryDoubleFPOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
if (FT->getNumParams() != 1 || FT->getReturnType() != Type::DoubleTy ||
|
|
FT->getParamType(0) != Type::DoubleTy)
|
|
return 0;
|
|
|
|
// If this is something like 'floor((double)floatval)', convert to floorf.
|
|
FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getOperand(1));
|
|
if (Cast == 0 || Cast->getOperand(0)->getType() != Type::FloatTy)
|
|
return 0;
|
|
|
|
// floor((double)floatval) -> (double)floorf(floatval)
|
|
Value *V = Cast->getOperand(0);
|
|
V = EmitUnaryFloatFnCall(V, Callee->getNameStart(), B);
|
|
return B.CreateFPExt(V, Type::DoubleTy);
|
|
}
|
|
};
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Integer Optimizations
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
//===---------------------------------------===//
|
|
// 'ffs*' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN FFSOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
// Just make sure this has 2 arguments of the same FP type, which match the
|
|
// result type.
|
|
if (FT->getNumParams() != 1 || FT->getReturnType() != Type::Int32Ty ||
|
|
!isa<IntegerType>(FT->getParamType(0)))
|
|
return 0;
|
|
|
|
Value *Op = CI->getOperand(1);
|
|
|
|
// Constant fold.
|
|
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
|
|
if (CI->getValue() == 0) // ffs(0) -> 0.
|
|
return Constant::getNullValue(CI->getType());
|
|
return ConstantInt::get(Type::Int32Ty, // ffs(c) -> cttz(c)+1
|
|
CI->getValue().countTrailingZeros()+1);
|
|
}
|
|
|
|
// ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0
|
|
const Type *ArgType = Op->getType();
|
|
Value *F = Intrinsic::getDeclaration(Callee->getParent(),
|
|
Intrinsic::cttz, &ArgType, 1);
|
|
Value *V = B.CreateCall(F, Op, "cttz");
|
|
V = B.CreateAdd(V, ConstantInt::get(Type::Int32Ty, 1), "tmp");
|
|
V = B.CreateIntCast(V, Type::Int32Ty, false, "tmp");
|
|
|
|
Value *Cond = B.CreateICmpNE(Op, Constant::getNullValue(ArgType), "tmp");
|
|
return B.CreateSelect(Cond, V, ConstantInt::get(Type::Int32Ty, 0));
|
|
}
|
|
};
|
|
|
|
//===---------------------------------------===//
|
|
// 'isdigit' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN IsDigitOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
// We require integer(i32)
|
|
if (FT->getNumParams() != 1 || !isa<IntegerType>(FT->getReturnType()) ||
|
|
FT->getParamType(0) != Type::Int32Ty)
|
|
return 0;
|
|
|
|
// isdigit(c) -> (c-'0') <u 10
|
|
Value *Op = CI->getOperand(1);
|
|
Op = B.CreateSub(Op, ConstantInt::get(Type::Int32Ty, '0'), "isdigittmp");
|
|
Op = B.CreateICmpULT(Op, ConstantInt::get(Type::Int32Ty, 10), "isdigit");
|
|
return B.CreateZExt(Op, CI->getType());
|
|
}
|
|
};
|
|
|
|
//===---------------------------------------===//
|
|
// 'isascii' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN IsAsciiOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
// We require integer(i32)
|
|
if (FT->getNumParams() != 1 || !isa<IntegerType>(FT->getReturnType()) ||
|
|
FT->getParamType(0) != Type::Int32Ty)
|
|
return 0;
|
|
|
|
// isascii(c) -> c <u 128
|
|
Value *Op = CI->getOperand(1);
|
|
Op = B.CreateICmpULT(Op, ConstantInt::get(Type::Int32Ty, 128), "isascii");
|
|
return B.CreateZExt(Op, CI->getType());
|
|
}
|
|
};
|
|
|
|
//===---------------------------------------===//
|
|
// 'abs', 'labs', 'llabs' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN AbsOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
// We require integer(integer) where the types agree.
|
|
if (FT->getNumParams() != 1 || !isa<IntegerType>(FT->getReturnType()) ||
|
|
FT->getParamType(0) != FT->getReturnType())
|
|
return 0;
|
|
|
|
// abs(x) -> x >s -1 ? x : -x
|
|
Value *Op = CI->getOperand(1);
|
|
Value *Pos = B.CreateICmpSGT(Op,ConstantInt::getAllOnesValue(Op->getType()),
|
|
"ispos");
|
|
Value *Neg = B.CreateNeg(Op, "neg");
|
|
return B.CreateSelect(Pos, Op, Neg);
|
|
}
|
|
};
|
|
|
|
|
|
//===---------------------------------------===//
|
|
// 'toascii' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN ToAsciiOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
// We require i32(i32)
|
|
if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
|
|
FT->getParamType(0) != Type::Int32Ty)
|
|
return 0;
|
|
|
|
// isascii(c) -> c & 0x7f
|
|
return B.CreateAnd(CI->getOperand(1), ConstantInt::get(CI->getType(),0x7F));
|
|
}
|
|
};
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Formatting and IO Optimizations
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
//===---------------------------------------===//
|
|
// 'printf' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN PrintFOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
// Require one fixed pointer argument and an integer/void result.
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
if (FT->getNumParams() < 1 || !isa<PointerType>(FT->getParamType(0)) ||
|
|
!(isa<IntegerType>(FT->getReturnType()) ||
|
|
FT->getReturnType() == Type::VoidTy))
|
|
return 0;
|
|
|
|
// Check for a fixed format string.
|
|
std::string FormatStr;
|
|
if (!GetConstantStringInfo(CI->getOperand(1), FormatStr))
|
|
return 0;
|
|
|
|
// Empty format string -> noop.
|
|
if (FormatStr.empty()) // Tolerate printf's declared void.
|
|
return CI->use_empty() ? (Value*)CI : ConstantInt::get(CI->getType(), 0);
|
|
|
|
// printf("x") -> putchar('x'), even for '%'.
|
|
if (FormatStr.size() == 1) {
|
|
EmitPutChar(ConstantInt::get(Type::Int32Ty, FormatStr[0]), B);
|
|
return CI->use_empty() ? (Value*)CI : ConstantInt::get(CI->getType(), 1);
|
|
}
|
|
|
|
// printf("foo\n") --> puts("foo")
|
|
if (FormatStr[FormatStr.size()-1] == '\n' &&
|
|
FormatStr.find('%') == std::string::npos) { // no format characters.
|
|
// Create a string literal with no \n on it. We expect the constant merge
|
|
// pass to be run after this pass, to merge duplicate strings.
|
|
FormatStr.erase(FormatStr.end()-1);
|
|
Constant *C = ConstantArray::get(FormatStr, true);
|
|
C = new GlobalVariable(C->getType(), true,GlobalVariable::InternalLinkage,
|
|
C, "str", Callee->getParent());
|
|
EmitPutS(C, B);
|
|
return CI->use_empty() ? (Value*)CI :
|
|
ConstantInt::get(CI->getType(), FormatStr.size()+1);
|
|
}
|
|
|
|
// Optimize specific format strings.
|
|
// printf("%c", chr) --> putchar(*(i8*)dst)
|
|
if (FormatStr == "%c" && CI->getNumOperands() > 2 &&
|
|
isa<IntegerType>(CI->getOperand(2)->getType())) {
|
|
EmitPutChar(CI->getOperand(2), B);
|
|
return CI->use_empty() ? (Value*)CI : ConstantInt::get(CI->getType(), 1);
|
|
}
|
|
|
|
// printf("%s\n", str) --> puts(str)
|
|
if (FormatStr == "%s\n" && CI->getNumOperands() > 2 &&
|
|
isa<PointerType>(CI->getOperand(2)->getType()) &&
|
|
CI->use_empty()) {
|
|
EmitPutS(CI->getOperand(2), B);
|
|
return CI;
|
|
}
|
|
return 0;
|
|
}
|
|
};
|
|
|
|
//===---------------------------------------===//
|
|
// 'sprintf' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN SPrintFOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
// Require two fixed pointer arguments and an integer result.
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
if (FT->getNumParams() != 2 || !isa<PointerType>(FT->getParamType(0)) ||
|
|
!isa<PointerType>(FT->getParamType(1)) ||
|
|
!isa<IntegerType>(FT->getReturnType()))
|
|
return 0;
|
|
|
|
// Check for a fixed format string.
|
|
std::string FormatStr;
|
|
if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
|
|
return 0;
|
|
|
|
// If we just have a format string (nothing else crazy) transform it.
|
|
if (CI->getNumOperands() == 3) {
|
|
// Make sure there's no % in the constant array. We could try to handle
|
|
// %% -> % in the future if we cared.
|
|
for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
|
|
if (FormatStr[i] == '%')
|
|
return 0; // we found a format specifier, bail out.
|
|
|
|
// sprintf(str, fmt) -> llvm.memcpy(str, fmt, strlen(fmt)+1, 1)
|
|
EmitMemCpy(CI->getOperand(1), CI->getOperand(2), // Copy the nul byte.
|
|
ConstantInt::get(TD->getIntPtrType(), FormatStr.size()+1),1,B);
|
|
return ConstantInt::get(CI->getType(), FormatStr.size());
|
|
}
|
|
|
|
// The remaining optimizations require the format string to be "%s" or "%c"
|
|
// and have an extra operand.
|
|
if (FormatStr.size() != 2 || FormatStr[0] != '%' || CI->getNumOperands() <4)
|
|
return 0;
|
|
|
|
// Decode the second character of the format string.
|
|
if (FormatStr[1] == 'c') {
|
|
// sprintf(dst, "%c", chr) --> *(i8*)dst = chr; *((i8*)dst+1) = 0
|
|
if (!isa<IntegerType>(CI->getOperand(3)->getType())) return 0;
|
|
Value *V = B.CreateTrunc(CI->getOperand(3), Type::Int8Ty, "char");
|
|
Value *Ptr = CastToCStr(CI->getOperand(1), B);
|
|
B.CreateStore(V, Ptr);
|
|
Ptr = B.CreateGEP(Ptr, ConstantInt::get(Type::Int32Ty, 1), "nul");
|
|
B.CreateStore(Constant::getNullValue(Type::Int8Ty), Ptr);
|
|
|
|
return ConstantInt::get(CI->getType(), 1);
|
|
}
|
|
|
|
if (FormatStr[1] == 's') {
|
|
// sprintf(dest, "%s", str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
|
|
if (!isa<PointerType>(CI->getOperand(3)->getType())) return 0;
|
|
|
|
Value *Len = EmitStrLen(CI->getOperand(3), B);
|
|
Value *IncLen = B.CreateAdd(Len, ConstantInt::get(Len->getType(), 1),
|
|
"leninc");
|
|
EmitMemCpy(CI->getOperand(1), CI->getOperand(3), IncLen, 1, B);
|
|
|
|
// The sprintf result is the unincremented number of bytes in the string.
|
|
return B.CreateIntCast(Len, CI->getType(), false);
|
|
}
|
|
return 0;
|
|
}
|
|
};
|
|
|
|
//===---------------------------------------===//
|
|
// 'fwrite' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN FWriteOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
// Require a pointer, an integer, an integer, a pointer, returning integer.
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
if (FT->getNumParams() != 4 || !isa<PointerType>(FT->getParamType(0)) ||
|
|
!isa<IntegerType>(FT->getParamType(1)) ||
|
|
!isa<IntegerType>(FT->getParamType(2)) ||
|
|
!isa<PointerType>(FT->getParamType(3)) ||
|
|
!isa<IntegerType>(FT->getReturnType()))
|
|
return 0;
|
|
|
|
// Get the element size and count.
|
|
ConstantInt *SizeC = dyn_cast<ConstantInt>(CI->getOperand(2));
|
|
ConstantInt *CountC = dyn_cast<ConstantInt>(CI->getOperand(3));
|
|
if (!SizeC || !CountC) return 0;
|
|
uint64_t Bytes = SizeC->getZExtValue()*CountC->getZExtValue();
|
|
|
|
// If this is writing zero records, remove the call (it's a noop).
|
|
if (Bytes == 0)
|
|
return ConstantInt::get(CI->getType(), 0);
|
|
|
|
// If this is writing one byte, turn it into fputc.
|
|
if (Bytes == 1) { // fwrite(S,1,1,F) -> fputc(S[0],F)
|
|
Value *Char = B.CreateLoad(CastToCStr(CI->getOperand(1), B), "char");
|
|
EmitFPutC(Char, CI->getOperand(4), B);
|
|
return ConstantInt::get(CI->getType(), 1);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
};
|
|
|
|
//===---------------------------------------===//
|
|
// 'fputs' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN FPutsOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
// Require two pointers. Also, we can't optimize if return value is used.
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
if (FT->getNumParams() != 2 || !isa<PointerType>(FT->getParamType(0)) ||
|
|
!isa<PointerType>(FT->getParamType(1)) ||
|
|
!CI->use_empty())
|
|
return 0;
|
|
|
|
// fputs(s,F) --> fwrite(s,1,strlen(s),F)
|
|
uint64_t Len = GetStringLength(CI->getOperand(1));
|
|
if (!Len) return 0;
|
|
EmitFWrite(CI->getOperand(1), ConstantInt::get(TD->getIntPtrType(), Len-1),
|
|
CI->getOperand(2), B);
|
|
return CI; // Known to have no uses (see above).
|
|
}
|
|
};
|
|
|
|
//===---------------------------------------===//
|
|
// 'fprintf' Optimizations
|
|
|
|
struct VISIBILITY_HIDDEN FPrintFOpt : public LibCallOptimization {
|
|
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
|
|
// Require two fixed paramters as pointers and integer result.
|
|
const FunctionType *FT = Callee->getFunctionType();
|
|
if (FT->getNumParams() != 2 || !isa<PointerType>(FT->getParamType(0)) ||
|
|
!isa<PointerType>(FT->getParamType(1)) ||
|
|
!isa<IntegerType>(FT->getReturnType()))
|
|
return 0;
|
|
|
|
// All the optimizations depend on the format string.
|
|
std::string FormatStr;
|
|
if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
|
|
return 0;
|
|
|
|
// fprintf(F, "foo") --> fwrite("foo", 3, 1, F)
|
|
if (CI->getNumOperands() == 3) {
|
|
for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
|
|
if (FormatStr[i] == '%') // Could handle %% -> % if we cared.
|
|
return 0; // We found a format specifier.
|
|
|
|
EmitFWrite(CI->getOperand(2), ConstantInt::get(TD->getIntPtrType(),
|
|
FormatStr.size()),
|
|
CI->getOperand(1), B);
|
|
return ConstantInt::get(CI->getType(), FormatStr.size());
|
|
}
|
|
|
|
// The remaining optimizations require the format string to be "%s" or "%c"
|
|
// and have an extra operand.
|
|
if (FormatStr.size() != 2 || FormatStr[0] != '%' || CI->getNumOperands() <4)
|
|
return 0;
|
|
|
|
// Decode the second character of the format string.
|
|
if (FormatStr[1] == 'c') {
|
|
// fprintf(F, "%c", chr) --> *(i8*)dst = chr
|
|
if (!isa<IntegerType>(CI->getOperand(3)->getType())) return 0;
|
|
EmitFPutC(CI->getOperand(3), CI->getOperand(1), B);
|
|
return ConstantInt::get(CI->getType(), 1);
|
|
}
|
|
|
|
if (FormatStr[1] == 's') {
|
|
// fprintf(F, "%s", str) -> fputs(str, F)
|
|
if (!isa<PointerType>(CI->getOperand(3)->getType()) || !CI->use_empty())
|
|
return 0;
|
|
EmitFPutS(CI->getOperand(3), CI->getOperand(1), B);
|
|
return CI;
|
|
}
|
|
return 0;
|
|
}
|
|
};
|
|
|
|
} // end anonymous namespace.
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// SimplifyLibCalls Pass Implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
namespace {
|
|
/// This pass optimizes well known library functions from libc and libm.
|
|
///
|
|
class VISIBILITY_HIDDEN SimplifyLibCalls : public FunctionPass {
|
|
StringMap<LibCallOptimization*> Optimizations;
|
|
// Miscellaneous LibCall Optimizations
|
|
ExitOpt Exit;
|
|
// String and Memory LibCall Optimizations
|
|
StrCatOpt StrCat; StrChrOpt StrChr; StrCmpOpt StrCmp; StrNCmpOpt StrNCmp;
|
|
StrCpyOpt StrCpy; StrLenOpt StrLen; MemCmpOpt MemCmp; MemCpyOpt MemCpy;
|
|
// Math Library Optimizations
|
|
PowOpt Pow; Exp2Opt Exp2; UnaryDoubleFPOpt UnaryDoubleFP;
|
|
// Integer Optimizations
|
|
FFSOpt FFS; AbsOpt Abs; IsDigitOpt IsDigit; IsAsciiOpt IsAscii;
|
|
ToAsciiOpt ToAscii;
|
|
// Formatting and IO Optimizations
|
|
SPrintFOpt SPrintF; PrintFOpt PrintF;
|
|
FWriteOpt FWrite; FPutsOpt FPuts; FPrintFOpt FPrintF;
|
|
public:
|
|
static char ID; // Pass identification
|
|
SimplifyLibCalls() : FunctionPass((intptr_t)&ID) {}
|
|
|
|
void InitOptimizations();
|
|
bool runOnFunction(Function &F);
|
|
|
|
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.addRequired<TargetData>();
|
|
}
|
|
};
|
|
char SimplifyLibCalls::ID = 0;
|
|
} // end anonymous namespace.
|
|
|
|
static RegisterPass<SimplifyLibCalls>
|
|
X("simplify-libcalls", "Simplify well-known library calls");
|
|
|
|
// Public interface to the Simplify LibCalls pass.
|
|
FunctionPass *llvm::createSimplifyLibCallsPass() {
|
|
return new SimplifyLibCalls();
|
|
}
|
|
|
|
/// Optimizations - Populate the Optimizations map with all the optimizations
|
|
/// we know.
|
|
void SimplifyLibCalls::InitOptimizations() {
|
|
// Miscellaneous LibCall Optimizations
|
|
Optimizations["exit"] = &Exit;
|
|
|
|
// String and Memory LibCall Optimizations
|
|
Optimizations["strcat"] = &StrCat;
|
|
Optimizations["strchr"] = &StrChr;
|
|
Optimizations["strcmp"] = &StrCmp;
|
|
Optimizations["strncmp"] = &StrNCmp;
|
|
Optimizations["strcpy"] = &StrCpy;
|
|
Optimizations["strlen"] = &StrLen;
|
|
Optimizations["memcmp"] = &MemCmp;
|
|
Optimizations["memcpy"] = &MemCpy;
|
|
|
|
// Math Library Optimizations
|
|
Optimizations["powf"] = &Pow;
|
|
Optimizations["pow"] = &Pow;
|
|
Optimizations["powl"] = &Pow;
|
|
Optimizations["exp2l"] = &Exp2;
|
|
Optimizations["exp2"] = &Exp2;
|
|
Optimizations["exp2f"] = &Exp2;
|
|
|
|
#ifdef HAVE_FLOORF
|
|
Optimizations["floor"] = &UnaryDoubleFP;
|
|
#endif
|
|
#ifdef HAVE_CEILF
|
|
Optimizations["ceil"] = &UnaryDoubleFP;
|
|
#endif
|
|
#ifdef HAVE_ROUNDF
|
|
Optimizations["round"] = &UnaryDoubleFP;
|
|
#endif
|
|
#ifdef HAVE_RINTF
|
|
Optimizations["rint"] = &UnaryDoubleFP;
|
|
#endif
|
|
#ifdef HAVE_NEARBYINTF
|
|
Optimizations["nearbyint"] = &UnaryDoubleFP;
|
|
#endif
|
|
|
|
// Integer Optimizations
|
|
Optimizations["ffs"] = &FFS;
|
|
Optimizations["ffsl"] = &FFS;
|
|
Optimizations["ffsll"] = &FFS;
|
|
Optimizations["abs"] = &Abs;
|
|
Optimizations["labs"] = &Abs;
|
|
Optimizations["llabs"] = &Abs;
|
|
Optimizations["isdigit"] = &IsDigit;
|
|
Optimizations["isascii"] = &IsAscii;
|
|
Optimizations["toascii"] = &ToAscii;
|
|
|
|
// Formatting and IO Optimizations
|
|
Optimizations["sprintf"] = &SPrintF;
|
|
Optimizations["printf"] = &PrintF;
|
|
Optimizations["fwrite"] = &FWrite;
|
|
Optimizations["fputs"] = &FPuts;
|
|
Optimizations["fprintf"] = &FPrintF;
|
|
}
|
|
|
|
|
|
/// runOnFunction - Top level algorithm.
|
|
///
|
|
bool SimplifyLibCalls::runOnFunction(Function &F) {
|
|
if (Optimizations.empty())
|
|
InitOptimizations();
|
|
|
|
const TargetData &TD = getAnalysis<TargetData>();
|
|
|
|
IRBuilder Builder;
|
|
|
|
bool Changed = false;
|
|
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
|
|
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
|
|
// Ignore non-calls.
|
|
CallInst *CI = dyn_cast<CallInst>(I++);
|
|
if (!CI) 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.
|
|
const char *CalleeName = Callee->getNameStart();
|
|
StringMap<LibCallOptimization*>::iterator OMI =
|
|
Optimizations.find(CalleeName, CalleeName+Callee->getNameLen());
|
|
if (OMI == Optimizations.end()) continue;
|
|
|
|
// Set the builder to the instruction after the call.
|
|
Builder.SetInsertPoint(BB, I);
|
|
|
|
// Try to optimize this call.
|
|
Value *Result = OMI->second->OptimizeCall(CI, TD, Builder);
|
|
if (Result == 0) continue;
|
|
|
|
DEBUG(DOUT << "SimplifyLibCalls simplified: " << *CI;
|
|
DOUT << " into: " << *Result << "\n");
|
|
|
|
// Something changed!
|
|
Changed = true;
|
|
++NumSimplified;
|
|
|
|
// Inspect the instruction after the call (which was potentially just
|
|
// added) next.
|
|
I = CI; ++I;
|
|
|
|
if (CI != Result && !CI->use_empty()) {
|
|
CI->replaceAllUsesWith(Result);
|
|
if (!Result->hasName())
|
|
Result->takeName(CI);
|
|
}
|
|
CI->eraseFromParent();
|
|
}
|
|
}
|
|
return Changed;
|
|
}
|
|
|
|
|
|
// TODO:
|
|
// Additional cases that we need to add to this file:
|
|
//
|
|
// cbrt:
|
|
// * cbrt(expN(X)) -> expN(x/3)
|
|
// * cbrt(sqrt(x)) -> pow(x,1/6)
|
|
// * cbrt(sqrt(x)) -> pow(x,1/9)
|
|
//
|
|
// cos, cosf, cosl:
|
|
// * cos(-x) -> cos(x)
|
|
//
|
|
// exp, expf, expl:
|
|
// * exp(log(x)) -> x
|
|
//
|
|
// log, logf, logl:
|
|
// * log(exp(x)) -> x
|
|
// * log(x**y) -> y*log(x)
|
|
// * log(exp(y)) -> y*log(e)
|
|
// * log(exp2(y)) -> y*log(2)
|
|
// * log(exp10(y)) -> y*log(10)
|
|
// * log(sqrt(x)) -> 0.5*log(x)
|
|
// * log(pow(x,y)) -> y*log(x)
|
|
//
|
|
// lround, lroundf, lroundl:
|
|
// * lround(cnst) -> cnst'
|
|
//
|
|
// memcmp:
|
|
// * memcmp(x,y,l) -> cnst
|
|
// (if all arguments are constant and strlen(x) <= l and strlen(y) <= l)
|
|
//
|
|
// memmove:
|
|
// * memmove(d,s,l,a) -> memcpy(d,s,l,a)
|
|
// (if s is a global constant array)
|
|
//
|
|
// pow, powf, powl:
|
|
// * pow(exp(x),y) -> exp(x*y)
|
|
// * pow(sqrt(x),y) -> pow(x,y*0.5)
|
|
// * pow(pow(x,y),z)-> pow(x,y*z)
|
|
//
|
|
// puts:
|
|
// * puts("") -> putchar("\n")
|
|
//
|
|
// round, roundf, roundl:
|
|
// * round(cnst) -> cnst'
|
|
//
|
|
// signbit:
|
|
// * signbit(cnst) -> cnst'
|
|
// * signbit(nncst) -> 0 (if pstv is a non-negative constant)
|
|
//
|
|
// sqrt, sqrtf, sqrtl:
|
|
// * sqrt(expN(x)) -> expN(x*0.5)
|
|
// * sqrt(Nroot(x)) -> pow(x,1/(2*N))
|
|
// * sqrt(pow(x,y)) -> pow(|x|,y*0.5)
|
|
//
|
|
// stpcpy:
|
|
// * stpcpy(str, "literal") ->
|
|
// llvm.memcpy(str,"literal",strlen("literal")+1,1)
|
|
// strrchr:
|
|
// * strrchr(s,c) -> reverse_offset_of_in(c,s)
|
|
// (if c is a constant integer and s is a constant string)
|
|
// * strrchr(s1,0) -> strchr(s1,0)
|
|
//
|
|
// strncat:
|
|
// * strncat(x,y,0) -> x
|
|
// * strncat(x,y,0) -> x (if strlen(y) = 0)
|
|
// * strncat(x,y,l) -> strcat(x,y) (if y and l are constants an l > strlen(y))
|
|
//
|
|
// strncpy:
|
|
// * strncpy(d,s,0) -> d
|
|
// * strncpy(d,s,l) -> memcpy(d,s,l,1)
|
|
// (if s and l are constants)
|
|
//
|
|
// strpbrk:
|
|
// * strpbrk(s,a) -> offset_in_for(s,a)
|
|
// (if s and a are both constant strings)
|
|
// * strpbrk(s,"") -> 0
|
|
// * strpbrk(s,a) -> strchr(s,a[0]) (if a is constant string of length 1)
|
|
//
|
|
// strspn, strcspn:
|
|
// * strspn(s,a) -> const_int (if both args are constant)
|
|
// * strspn("",a) -> 0
|
|
// * strspn(s,"") -> 0
|
|
// * strcspn(s,a) -> const_int (if both args are constant)
|
|
// * strcspn("",a) -> 0
|
|
// * strcspn(s,"") -> strlen(a)
|
|
//
|
|
// strstr:
|
|
// * strstr(x,x) -> x
|
|
// * strstr(s1,s2) -> offset_of_s2_in(s1)
|
|
// (if s1 and s2 are constant strings)
|
|
//
|
|
// tan, tanf, tanl:
|
|
// * tan(atan(x)) -> x
|
|
//
|
|
// trunc, truncf, truncl:
|
|
// * trunc(cnst) -> cnst'
|
|
//
|
|
//
|