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https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117667 91177308-0d34-0410-b5e6-96231b3b80d8
286 lines
11 KiB
C++
286 lines
11 KiB
C++
//===-- Analysis.cpp - CodeGen LLVM IR Analysis Utilities --*- C++ ------*-===//
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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 defines several CodeGen-specific LLVM IR analysis utilties.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/Analysis.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Function.h"
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#include "llvm/Instructions.h"
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#include "llvm/IntrinsicInst.h"
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#include "llvm/LLVMContext.h"
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#include "llvm/Module.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Target/TargetLowering.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/MathExtras.h"
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using namespace llvm;
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/// ComputeLinearIndex - Given an LLVM IR aggregate type and a sequence
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/// of insertvalue or extractvalue indices that identify a member, return
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/// the linearized index of the start of the member.
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///
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unsigned llvm::ComputeLinearIndex(const Type *Ty,
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const unsigned *Indices,
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const unsigned *IndicesEnd,
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unsigned CurIndex) {
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// Base case: We're done.
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if (Indices && Indices == IndicesEnd)
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return CurIndex;
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// Given a struct type, recursively traverse the elements.
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if (const StructType *STy = dyn_cast<StructType>(Ty)) {
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for (StructType::element_iterator EB = STy->element_begin(),
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EI = EB,
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EE = STy->element_end();
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EI != EE; ++EI) {
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if (Indices && *Indices == unsigned(EI - EB))
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return ComputeLinearIndex(*EI, Indices+1, IndicesEnd, CurIndex);
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CurIndex = ComputeLinearIndex(*EI, 0, 0, CurIndex);
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}
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return CurIndex;
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}
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// Given an array type, recursively traverse the elements.
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else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
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const Type *EltTy = ATy->getElementType();
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for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i) {
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if (Indices && *Indices == i)
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return ComputeLinearIndex(EltTy, Indices+1, IndicesEnd, CurIndex);
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CurIndex = ComputeLinearIndex(EltTy, 0, 0, CurIndex);
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}
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return CurIndex;
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}
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// We haven't found the type we're looking for, so keep searching.
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return CurIndex + 1;
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}
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/// ComputeValueVTs - Given an LLVM IR type, compute a sequence of
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/// EVTs that represent all the individual underlying
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/// non-aggregate types that comprise it.
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///
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/// If Offsets is non-null, it points to a vector to be filled in
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/// with the in-memory offsets of each of the individual values.
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///
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void llvm::ComputeValueVTs(const TargetLowering &TLI, const Type *Ty,
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SmallVectorImpl<EVT> &ValueVTs,
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SmallVectorImpl<uint64_t> *Offsets,
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uint64_t StartingOffset) {
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// Given a struct type, recursively traverse the elements.
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if (const StructType *STy = dyn_cast<StructType>(Ty)) {
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const StructLayout *SL = TLI.getTargetData()->getStructLayout(STy);
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for (StructType::element_iterator EB = STy->element_begin(),
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EI = EB,
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EE = STy->element_end();
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EI != EE; ++EI)
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ComputeValueVTs(TLI, *EI, ValueVTs, Offsets,
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StartingOffset + SL->getElementOffset(EI - EB));
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return;
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}
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// Given an array type, recursively traverse the elements.
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if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
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const Type *EltTy = ATy->getElementType();
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uint64_t EltSize = TLI.getTargetData()->getTypeAllocSize(EltTy);
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for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i)
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ComputeValueVTs(TLI, EltTy, ValueVTs, Offsets,
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StartingOffset + i * EltSize);
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return;
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}
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// Interpret void as zero return values.
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if (Ty->isVoidTy())
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return;
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// Base case: we can get an EVT for this LLVM IR type.
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ValueVTs.push_back(TLI.getValueType(Ty));
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if (Offsets)
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Offsets->push_back(StartingOffset);
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}
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/// ExtractTypeInfo - Returns the type info, possibly bitcast, encoded in V.
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GlobalVariable *llvm::ExtractTypeInfo(Value *V) {
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V = V->stripPointerCasts();
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GlobalVariable *GV = dyn_cast<GlobalVariable>(V);
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if (GV && GV->getName() == "llvm.eh.catch.all.value") {
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assert(GV->hasInitializer() &&
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"The EH catch-all value must have an initializer");
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Value *Init = GV->getInitializer();
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GV = dyn_cast<GlobalVariable>(Init);
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if (!GV) V = cast<ConstantPointerNull>(Init);
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}
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assert((GV || isa<ConstantPointerNull>(V)) &&
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"TypeInfo must be a global variable or NULL");
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return GV;
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}
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/// hasInlineAsmMemConstraint - Return true if the inline asm instruction being
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/// processed uses a memory 'm' constraint.
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bool
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llvm::hasInlineAsmMemConstraint(InlineAsm::ConstraintInfoVector &CInfos,
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const TargetLowering &TLI) {
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for (unsigned i = 0, e = CInfos.size(); i != e; ++i) {
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InlineAsm::ConstraintInfo &CI = CInfos[i];
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for (unsigned j = 0, ee = CI.Codes.size(); j != ee; ++j) {
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TargetLowering::ConstraintType CType = TLI.getConstraintType(CI.Codes[j]);
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if (CType == TargetLowering::C_Memory)
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return true;
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}
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// Indirect operand accesses access memory.
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if (CI.isIndirect)
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return true;
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}
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return false;
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}
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/// getFCmpCondCode - Return the ISD condition code corresponding to
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/// the given LLVM IR floating-point condition code. This includes
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/// consideration of global floating-point math flags.
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///
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ISD::CondCode llvm::getFCmpCondCode(FCmpInst::Predicate Pred) {
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ISD::CondCode FPC, FOC;
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switch (Pred) {
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case FCmpInst::FCMP_FALSE: FOC = FPC = ISD::SETFALSE; break;
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case FCmpInst::FCMP_OEQ: FOC = ISD::SETEQ; FPC = ISD::SETOEQ; break;
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case FCmpInst::FCMP_OGT: FOC = ISD::SETGT; FPC = ISD::SETOGT; break;
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case FCmpInst::FCMP_OGE: FOC = ISD::SETGE; FPC = ISD::SETOGE; break;
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case FCmpInst::FCMP_OLT: FOC = ISD::SETLT; FPC = ISD::SETOLT; break;
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case FCmpInst::FCMP_OLE: FOC = ISD::SETLE; FPC = ISD::SETOLE; break;
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case FCmpInst::FCMP_ONE: FOC = ISD::SETNE; FPC = ISD::SETONE; break;
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case FCmpInst::FCMP_ORD: FOC = FPC = ISD::SETO; break;
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case FCmpInst::FCMP_UNO: FOC = FPC = ISD::SETUO; break;
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case FCmpInst::FCMP_UEQ: FOC = ISD::SETEQ; FPC = ISD::SETUEQ; break;
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case FCmpInst::FCMP_UGT: FOC = ISD::SETGT; FPC = ISD::SETUGT; break;
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case FCmpInst::FCMP_UGE: FOC = ISD::SETGE; FPC = ISD::SETUGE; break;
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case FCmpInst::FCMP_ULT: FOC = ISD::SETLT; FPC = ISD::SETULT; break;
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case FCmpInst::FCMP_ULE: FOC = ISD::SETLE; FPC = ISD::SETULE; break;
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case FCmpInst::FCMP_UNE: FOC = ISD::SETNE; FPC = ISD::SETUNE; break;
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case FCmpInst::FCMP_TRUE: FOC = FPC = ISD::SETTRUE; break;
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default:
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llvm_unreachable("Invalid FCmp predicate opcode!");
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FOC = FPC = ISD::SETFALSE;
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break;
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}
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if (NoNaNsFPMath)
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return FOC;
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else
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return FPC;
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}
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/// getICmpCondCode - Return the ISD condition code corresponding to
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/// the given LLVM IR integer condition code.
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///
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ISD::CondCode llvm::getICmpCondCode(ICmpInst::Predicate Pred) {
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switch (Pred) {
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case ICmpInst::ICMP_EQ: return ISD::SETEQ;
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case ICmpInst::ICMP_NE: return ISD::SETNE;
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case ICmpInst::ICMP_SLE: return ISD::SETLE;
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case ICmpInst::ICMP_ULE: return ISD::SETULE;
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case ICmpInst::ICMP_SGE: return ISD::SETGE;
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case ICmpInst::ICMP_UGE: return ISD::SETUGE;
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case ICmpInst::ICMP_SLT: return ISD::SETLT;
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case ICmpInst::ICMP_ULT: return ISD::SETULT;
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case ICmpInst::ICMP_SGT: return ISD::SETGT;
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case ICmpInst::ICMP_UGT: return ISD::SETUGT;
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default:
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llvm_unreachable("Invalid ICmp predicate opcode!");
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return ISD::SETNE;
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}
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}
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/// Test if the given instruction is in a position to be optimized
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/// with a tail-call. This roughly means that it's in a block with
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/// a return and there's nothing that needs to be scheduled
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/// between it and the return.
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///
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/// This function only tests target-independent requirements.
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bool llvm::isInTailCallPosition(ImmutableCallSite CS, Attributes CalleeRetAttr,
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const TargetLowering &TLI) {
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const Instruction *I = CS.getInstruction();
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const BasicBlock *ExitBB = I->getParent();
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const TerminatorInst *Term = ExitBB->getTerminator();
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const ReturnInst *Ret = dyn_cast<ReturnInst>(Term);
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const Function *F = ExitBB->getParent();
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// The block must end in a return statement or unreachable.
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//
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// FIXME: Decline tailcall if it's not guaranteed and if the block ends in
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// an unreachable, for now. The way tailcall optimization is currently
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// implemented means it will add an epilogue followed by a jump. That is
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// not profitable. Also, if the callee is a special function (e.g.
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// longjmp on x86), it can end up causing miscompilation that has not
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// been fully understood.
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if (!Ret &&
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(!GuaranteedTailCallOpt || !isa<UnreachableInst>(Term))) return false;
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// If I will have a chain, make sure no other instruction that will have a
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// chain interposes between I and the return.
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if (I->mayHaveSideEffects() || I->mayReadFromMemory() ||
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!I->isSafeToSpeculativelyExecute())
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for (BasicBlock::const_iterator BBI = prior(prior(ExitBB->end())); ;
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--BBI) {
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if (&*BBI == I)
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break;
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// Debug info intrinsics do not get in the way of tail call optimization.
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if (isa<DbgInfoIntrinsic>(BBI))
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continue;
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if (BBI->mayHaveSideEffects() || BBI->mayReadFromMemory() ||
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!BBI->isSafeToSpeculativelyExecute())
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return false;
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}
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// If the block ends with a void return or unreachable, it doesn't matter
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// what the call's return type is.
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if (!Ret || Ret->getNumOperands() == 0) return true;
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// If the return value is undef, it doesn't matter what the call's
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// return type is.
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if (isa<UndefValue>(Ret->getOperand(0))) return true;
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// Conservatively require the attributes of the call to match those of
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// the return. Ignore noalias because it doesn't affect the call sequence.
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unsigned CallerRetAttr = F->getAttributes().getRetAttributes();
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if ((CalleeRetAttr ^ CallerRetAttr) & ~Attribute::NoAlias)
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return false;
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// It's not safe to eliminate the sign / zero extension of the return value.
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if ((CallerRetAttr & Attribute::ZExt) || (CallerRetAttr & Attribute::SExt))
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return false;
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// Otherwise, make sure the unmodified return value of I is the return value.
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for (const Instruction *U = dyn_cast<Instruction>(Ret->getOperand(0)); ;
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U = dyn_cast<Instruction>(U->getOperand(0))) {
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if (!U)
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return false;
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if (!U->hasOneUse())
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return false;
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if (U == I)
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break;
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// Check for a truly no-op truncate.
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if (isa<TruncInst>(U) &&
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TLI.isTruncateFree(U->getOperand(0)->getType(), U->getType()))
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continue;
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// Check for a truly no-op bitcast.
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if (isa<BitCastInst>(U) &&
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(U->getOperand(0)->getType() == U->getType() ||
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(U->getOperand(0)->getType()->isPointerTy() &&
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U->getType()->isPointerTy())))
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continue;
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// Otherwise it's not a true no-op.
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return false;
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}
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return true;
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}
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