forked from OSchip/llvm-project
[Evaluator] Improve evaluation of call instruction
Recommit of r335324 after buildbot failure fix llvm-svn: 336059
This commit is contained in:
Eugene Leviant
parent
49997adc88
commit
6e4134459b
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@ -18,6 +18,7 @@
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/IR/BasicBlock.h"
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#include "llvm/IR/CallSite.h"
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#include "llvm/IR/GlobalVariable.h"
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#include "llvm/IR/Value.h"
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#include "llvm/Support/Casting.h"
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@ -73,6 +74,18 @@ public:
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ValueStack.back()[V] = C;
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}
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/// Given call site return callee and list of its formal arguments
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Function *getCalleeWithFormalArgs(CallSite &CS,
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SmallVector<Constant *, 8> &Formals);
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/// Given call site and callee returns list of callee formal argument
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/// values converting them when necessary
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bool getFormalParams(CallSite &CS, Function *F,
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SmallVector<Constant *, 8> &Formals);
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/// Casts call result to a type of bitcast call expression
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Constant *castCallResultIfNeeded(Value *CallExpr, Constant *RV);
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const DenseMap<Constant*, Constant*> &getMutatedMemory() const {
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return MutatedMemory;
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}
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@ -217,6 +217,60 @@ Constant *Evaluator::ComputeLoadResult(Constant *P) {
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return nullptr; // don't know how to evaluate.
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}
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Function *
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Evaluator::getCalleeWithFormalArgs(CallSite &CS,
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SmallVector<Constant *, 8> &Formals) {
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auto *V = CS.getCalledValue();
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if (auto *Fn = dyn_cast<Function>(getVal(V)))
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return getFormalParams(CS, Fn, Formals) ? Fn : nullptr;
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auto *CE = dyn_cast<ConstantExpr>(V);
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if (!CE || CE->getOpcode() != Instruction::BitCast ||
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!getFormalParams(CS, cast<Function>(CE->getOperand(0)), Formals))
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return nullptr;
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return dyn_cast<Function>(
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ConstantFoldLoadThroughBitcast(CE, CE->getOperand(0)->getType(), DL));
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}
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bool Evaluator::getFormalParams(CallSite &CS, Function *F,
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SmallVector<Constant *, 8> &Formals) {
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auto *FTy = F->getFunctionType();
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if (FTy->getNumParams() > CS.getNumArgOperands()) {
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LLVM_DEBUG(dbgs() << "Too few arguments for function.\n");
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return false;
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}
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auto ArgI = CS.arg_begin();
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for (auto ParI = FTy->param_begin(), ParE = FTy->param_end(); ParI != ParE;
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++ParI) {
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auto *ArgC = ConstantFoldLoadThroughBitcast(getVal(*ArgI), *ParI, DL);
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if (!ArgC) {
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LLVM_DEBUG(dbgs() << "Can not convert function argument.\n");
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return false;
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}
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Formals.push_back(ArgC);
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++ArgI;
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}
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return true;
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}
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/// If call expression contains bitcast then we may need to cast
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/// evaluated return value to a type of the call expression.
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Constant *Evaluator::castCallResultIfNeeded(Value *CallExpr, Constant *RV) {
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ConstantExpr *CE = dyn_cast<ConstantExpr>(CallExpr);
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if (!RV || !CE || CE->getOpcode() != Instruction::BitCast)
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return RV;
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if (auto *FT =
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dyn_cast<FunctionType>(CE->getType()->getPointerElementType())) {
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RV = ConstantFoldLoadThroughBitcast(RV, FT->getReturnType(), DL);
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if (!RV)
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LLVM_DEBUG(dbgs() << "Failed to fold bitcast call expr\n");
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}
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return RV;
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}
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/// Evaluate all instructions in block BB, returning true if successful, false
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/// if we can't evaluate it. NewBB returns the next BB that control flows into,
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/// or null upon return.
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@ -465,20 +519,19 @@ bool Evaluator::EvaluateBlock(BasicBlock::iterator CurInst,
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}
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// Resolve function pointers.
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Function *Callee = dyn_cast<Function>(getVal(CS.getCalledValue()));
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SmallVector<Constant *, 8> Formals;
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Function *Callee = getCalleeWithFormalArgs(CS, Formals);
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if (!Callee || Callee->isInterposable()) {
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LLVM_DEBUG(dbgs() << "Can not resolve function pointer.\n");
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return false; // Cannot resolve.
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}
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SmallVector<Constant*, 8> Formals;
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for (User::op_iterator i = CS.arg_begin(), e = CS.arg_end(); i != e; ++i)
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Formals.push_back(getVal(*i));
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if (Callee->isDeclaration()) {
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// If this is a function we can constant fold, do it.
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if (Constant *C = ConstantFoldCall(CS, Callee, Formals, TLI)) {
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InstResult = C;
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InstResult = castCallResultIfNeeded(CS.getCalledValue(), C);
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if (!InstResult)
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return false;
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LLVM_DEBUG(dbgs() << "Constant folded function call. Result: "
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<< *InstResult << "\n");
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} else {
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@ -499,7 +552,9 @@ bool Evaluator::EvaluateBlock(BasicBlock::iterator CurInst,
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return false;
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}
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ValueStack.pop_back();
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InstResult = RetVal;
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InstResult = castCallResultIfNeeded(CS.getCalledValue(), RetVal);
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if (RetVal && !InstResult)
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return false;
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if (InstResult) {
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LLVM_DEBUG(dbgs() << "Successfully evaluated function. Result: "
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@ -0,0 +1,99 @@
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; Checks for few bitcasted call evaluation errors
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; REQUIRES: asserts
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; RUN: opt -globalopt -instcombine -S -debug-only=evaluator %s -o %t 2>&1 | FileCheck %s
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; CHECK: Failed to fold bitcast call expr
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; CHECK: Can not convert function argument
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target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-apple-macosx10.12.0"
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%struct.S = type { i32 }
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%struct.Q = type { i32 }
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%struct.Foo = type { i32 }
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@_s = global %struct.S zeroinitializer, align 4
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@_q = global %struct.Q zeroinitializer, align 4
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@llvm.global_ctors = appending global [2 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 65535, void ()* @_GLOBAL__sub_I_main2.cpp, i8* null }, { i32, void ()*, i8* } { i32 65535, void ()* @_GLOBAL__sub_I_main3.cpp, i8* null }]
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define internal void @__cxx_global_var_init() section "__TEXT,__StaticInit,regular,pure_instructions" {
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call void @_ZN1SC1Ev(%struct.S* @_s)
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ret void
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}
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define linkonce_odr void @_ZN1SC1Ev(%struct.S*) unnamed_addr align 2 {
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%2 = alloca %struct.S*, align 8
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store %struct.S* %0, %struct.S** %2, align 8
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%3 = load %struct.S*, %struct.S** %2, align 8
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call void @_ZN1SC2Ev(%struct.S* %3)
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ret void
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}
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define internal void @__cxx_global_var_init.1() #0 section "__TEXT,__StaticInit,regular,pure_instructions" {
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call void @_ZN1QC1Ev(%struct.Q* @_q)
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ret void
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}
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define linkonce_odr void @_ZN1QC1Ev(%struct.Q*) unnamed_addr align 2 {
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%2 = alloca %struct.Q*, align 8
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store %struct.Q* %0, %struct.Q** %2, align 8
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%3 = load %struct.Q*, %struct.Q** %2, align 8
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call void @_ZN1QC2Ev(%struct.Q* %3)
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ret void
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}
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define i32 @main() {
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%1 = alloca i32, align 4
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store i32 0, i32* %1, align 4
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ret i32 0
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}
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define linkonce_odr void @_ZN1SC2Ev(%struct.S*) unnamed_addr align 2 {
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%2 = alloca %struct.S*, align 8
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%3 = alloca %struct.Foo, align 4
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store %struct.S* %0, %struct.S** %2, align 8
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%4 = load %struct.S*, %struct.S** %2, align 8
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%5 = getelementptr inbounds %struct.S, %struct.S* %4, i32 0, i32 0
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%6 = call i32 bitcast (%struct.Foo* ()* @_ZL3foov to i32 ()*)()
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%7 = getelementptr inbounds %struct.Foo, %struct.Foo* %3, i32 0, i32 0
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store i32 %6, i32* %7, align 4
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%8 = getelementptr inbounds %struct.Foo, %struct.Foo* %3, i32 0, i32 0
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%9 = load i32, i32* %8, align 4
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store i32 %9, i32* %5, align 4
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ret void
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}
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define internal %struct.Foo* @_ZL3foov() {
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ret %struct.Foo* null
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}
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define linkonce_odr void @_ZN1QC2Ev(%struct.Q*) unnamed_addr align 2 {
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%2 = alloca %struct.Q*, align 8
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store %struct.Q* %0, %struct.Q** %2, align 8
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%3 = load %struct.Q*, %struct.Q** %2, align 8
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%4 = getelementptr inbounds %struct.Q, %struct.Q* %3, i32 0, i32 0
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%5 = call i32 bitcast (i32 (i32)* @_ZL3baz3Foo to i32 (%struct.Foo*)*)(%struct.Foo* null)
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store i32 %5, i32* %4, align 4
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ret void
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}
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define internal i32 @_ZL3baz3Foo(i32) {
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%2 = alloca %struct.Foo, align 4
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%3 = getelementptr inbounds %struct.Foo, %struct.Foo* %2, i32 0, i32 0
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store i32 %0, i32* %3, align 4
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%4 = getelementptr inbounds %struct.Foo, %struct.Foo* %2, i32 0, i32 0
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%5 = load i32, i32* %4, align 4
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ret i32 %5
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}
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; Function Attrs: noinline ssp uwtable
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define internal void @_GLOBAL__sub_I_main2.cpp() section "__TEXT,__StaticInit,regular,pure_instructions" {
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call void @__cxx_global_var_init()
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ret void
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}
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define internal void @_GLOBAL__sub_I_main3.cpp() section "__TEXT,__StaticInit,regular,pure_instructions" {
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call void @__cxx_global_var_init.1()
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ret void
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}
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@ -0,0 +1,85 @@
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; Checks if bitcasted call expression can be evaluated
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; Given call expresion:
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; %struct.Bar* bitcast (%struct.Foo* (%struct.Foo*)* @_ZL3fooP3Foo to %struct.Bar* (%struct.Bar*)*)(%struct.Bar* @gBar)
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; We evaluate call to function @_ZL3fooP3Foo casting both parameter and return value
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; Given call expression:
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; void bitcast (void (%struct.Foo*)* @_ZL3bazP3Foo to void (%struct.Bar*)*)(%struct.Bar* @gBar)
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; We evaluate call to function _ZL3bazP3Foo casting its parameter and check that evaluated value (nullptr)
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; is handled correctly
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; RUN: opt -globalopt -instcombine -S %s -o - | FileCheck %s
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; CHECK: @gBar = local_unnamed_addr global %struct.Bar { i32 2 }
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; CHECK-NEXT: @_s = local_unnamed_addr global %struct.S { i32 1 }, align 4
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; CHECK-NEXT: @llvm.global_ctors = appending global [0 x { i32, void ()*, i8* }] zeroinitializer
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; CHECK: define i32 @main()
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; CHECK-NEXT: ret i32 0
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target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-apple-macosx10.12.0"
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%struct.Bar = type { i32 }
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%struct.S = type { i32 }
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%struct.Foo = type { i32 }
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@gBar = global %struct.Bar zeroinitializer, align 4
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@_s = global %struct.S zeroinitializer, align 4
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@llvm.global_ctors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 65535, void ()* @_GLOBAL__sub_I_main.cpp, i8* null }]
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define internal void @__cxx_global_var_init() section "__TEXT,__StaticInit,regular,pure_instructions" {
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call void @_ZN1SC1Ev(%struct.S* @_s)
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ret void
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}
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define linkonce_odr void @_ZN1SC1Ev(%struct.S*) unnamed_addr align 2 {
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%2 = alloca %struct.S*, align 8
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store %struct.S* %0, %struct.S** %2, align 8
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%3 = load %struct.S*, %struct.S** %2, align 8
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call void @_ZN1SC2Ev(%struct.S* %3)
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ret void
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}
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define i32 @main() {
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%1 = alloca i32, align 4
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store i32 0, i32* %1, align 4
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ret i32 0
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}
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define linkonce_odr void @_ZN1SC2Ev(%struct.S*) unnamed_addr align 2 {
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%2 = alloca %struct.S*, align 8
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store %struct.S* %0, %struct.S** %2, align 8
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%3 = load %struct.S*, %struct.S** %2, align 8
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%4 = getelementptr inbounds %struct.S, %struct.S* %3, i32 0, i32 0
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%5 = call %struct.Bar* bitcast (%struct.Foo* (%struct.Foo*)* @_ZL3fooP3Foo to %struct.Bar* (%struct.Bar*)*)(%struct.Bar* @gBar)
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%6 = getelementptr inbounds %struct.Bar, %struct.Bar* %5, i32 0, i32 0
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%7 = load i32, i32* %6, align 4
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store i32 %7, i32* %4, align 4
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call void bitcast (void (%struct.Foo*)* @_ZL3bazP3Foo to void (%struct.Bar*)*)(%struct.Bar* @gBar)
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ret void
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}
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define internal %struct.Foo* @_ZL3fooP3Foo(%struct.Foo*) {
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%2 = alloca %struct.Foo*, align 8
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store %struct.Foo* %0, %struct.Foo** %2, align 8
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%3 = load %struct.Foo*, %struct.Foo** %2, align 8
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%4 = getelementptr inbounds %struct.Foo, %struct.Foo* %3, i32 0, i32 0
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store i32 1, i32* %4, align 4
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%5 = load %struct.Foo*, %struct.Foo** %2, align 8
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ret %struct.Foo* %5
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}
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define internal void @_ZL3bazP3Foo(%struct.Foo*) {
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%2 = alloca %struct.Foo*, align 8
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store %struct.Foo* %0, %struct.Foo** %2, align 8
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%3 = load %struct.Foo*, %struct.Foo** %2, align 8
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%4 = getelementptr inbounds %struct.Foo, %struct.Foo* %3, i32 0, i32 0
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store i32 2, i32* %4, align 4
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ret void
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}
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; Function Attrs: noinline ssp uwtable
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define internal void @_GLOBAL__sub_I_main.cpp() section "__TEXT,__StaticInit,regular,pure_instructions" {
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call void @__cxx_global_var_init()
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ret void
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}
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@ -0,0 +1,55 @@
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; Check if we can evaluate a bitcasted call to a function which is constant folded.
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; Evaluator folds call to fmodf, replacing it with constant value in case both operands
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; are known at compile time.
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; RUN: opt -globalopt -instcombine %s -S -o - | FileCheck %s
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; CHECK: @_q = dso_local local_unnamed_addr global %struct.Q { i32 1066527622 }
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; CHECK: define dso_local i32 @main
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; CHECK-NEXT: %[[V:.+]] = load i32, i32* getelementptr inbounds (%struct.Q, %struct.Q* @_q, i64 0, i32 0)
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; CHECK-NEXT: ret i32 %[[V]]
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source_filename = "main.cpp"
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-none-linux-gnu"
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%struct.Q = type { i32 }
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$_ZN1QC2Ev = comdat any
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@_q = dso_local global %struct.Q zeroinitializer, align 4
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@llvm.global_ctors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 65535, void ()* @_GLOBAL__sub_I_main.cpp, i8* null }]
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define internal void @__cxx_global_var_init() section ".text.startup" {
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call void @_ZN1QC2Ev(%struct.Q* @_q)
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ret void
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}
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define linkonce_odr dso_local void @_ZN1QC2Ev(%struct.Q*) unnamed_addr #1 comdat align 2 {
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%2 = alloca %struct.Q*, align 8
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store %struct.Q* %0, %struct.Q** %2, align 8
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%3 = load %struct.Q*, %struct.Q** %2, align 8
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%4 = getelementptr inbounds %struct.Q, %struct.Q* %3, i32 0, i32 0
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%5 = call i32 bitcast (float (float, float)* @fmodf to i32 (float, float)*)(float 0x40091EB860000000, float 2.000000e+00)
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store i32 %5, i32* %4, align 4
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ret void
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}
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define dso_local i32 @main(i32, i8**) {
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%3 = alloca i32, align 4
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%4 = alloca i32, align 4
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%5 = alloca i8**, align 8
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store i32 0, i32* %3, align 4
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store i32 %0, i32* %4, align 4
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store i8** %1, i8*** %5, align 8
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%6 = load i32, i32* getelementptr inbounds (%struct.Q, %struct.Q* @_q, i32 0, i32 0), align 4
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ret i32 %6
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}
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; Function Attrs: nounwind
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declare dso_local float @fmodf(float, float)
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; Function Attrs: noinline uwtable
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define internal void @_GLOBAL__sub_I_main.cpp() section ".text.startup" {
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call void @__cxx_global_var_init()
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ret void
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}
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