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3deb5ec521
A block reachable from the entry block can't have any route to a block that's not reachable from the entry block (if it did, that route would make it reachable from the entry block). That is the intended performance optimization for isPotentiallyReachable. For the case where we ask whether an unreachable from entry block has a route to a reachable from entry block, we can't conclude one way or the other. Fix a bug where we claimed there could be no such route. The fix in rL357425 ironically reintroduced the very bug it was fixing but only when a DominatorTree is provided. This fixes the remaining bug. llvm-svn: 357734
508 lines
14 KiB
C++
508 lines
14 KiB
C++
//===- CFGTest.cpp - CFG tests --------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/CFG.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/Analysis/LoopInfo.h"
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#include "llvm/AsmParser/Parser.h"
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#include "llvm/IR/Dominators.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/InstIterator.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/LegacyPassManager.h"
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#include "llvm/IR/Module.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/SourceMgr.h"
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#include "gtest/gtest.h"
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using namespace llvm;
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namespace {
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// This fixture assists in running the isPotentiallyReachable utility four ways
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// and ensuring it produces the correct answer each time.
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class IsPotentiallyReachableTest : public testing::Test {
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protected:
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void ParseAssembly(const char *Assembly) {
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SMDiagnostic Error;
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M = parseAssemblyString(Assembly, Error, Context);
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std::string errMsg;
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raw_string_ostream os(errMsg);
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Error.print("", os);
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// A failure here means that the test itself is buggy.
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if (!M)
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report_fatal_error(os.str().c_str());
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Function *F = M->getFunction("test");
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if (F == nullptr)
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report_fatal_error("Test must have a function named @test");
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A = B = nullptr;
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for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
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if (I->hasName()) {
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if (I->getName() == "A")
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A = &*I;
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else if (I->getName() == "B")
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B = &*I;
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}
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}
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if (A == nullptr)
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report_fatal_error("@test must have an instruction %A");
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if (B == nullptr)
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report_fatal_error("@test must have an instruction %B");
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assert(ExclusionSet.empty());
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for (auto I = F->begin(), E = F->end(); I != E; ++I) {
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if (I->hasName() && I->getName().startswith("excluded"))
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ExclusionSet.insert(&*I);
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}
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}
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void ExpectPath(bool ExpectedResult) {
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static char ID;
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class IsPotentiallyReachableTestPass : public FunctionPass {
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public:
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IsPotentiallyReachableTestPass(bool ExpectedResult, Instruction *A,
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Instruction *B,
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SmallPtrSet<BasicBlock *, 4> ExclusionSet)
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: FunctionPass(ID), ExpectedResult(ExpectedResult), A(A), B(B),
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ExclusionSet(ExclusionSet) {}
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static int initialize() {
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PassInfo *PI = new PassInfo("isPotentiallyReachable testing pass", "",
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&ID, nullptr, true, true);
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PassRegistry::getPassRegistry()->registerPass(*PI, false);
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initializeLoopInfoWrapperPassPass(*PassRegistry::getPassRegistry());
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initializeDominatorTreeWrapperPassPass(
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*PassRegistry::getPassRegistry());
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return 0;
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}
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.setPreservesAll();
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AU.addRequired<LoopInfoWrapperPass>();
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AU.addRequired<DominatorTreeWrapperPass>();
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}
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bool runOnFunction(Function &F) override {
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if (!F.hasName() || F.getName() != "test")
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return false;
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LoopInfo *LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
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DominatorTree *DT =
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&getAnalysis<DominatorTreeWrapperPass>().getDomTree();
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EXPECT_EQ(isPotentiallyReachable(A, B, &ExclusionSet, nullptr, nullptr),
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ExpectedResult);
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EXPECT_EQ(isPotentiallyReachable(A, B, &ExclusionSet, DT, nullptr),
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ExpectedResult);
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EXPECT_EQ(isPotentiallyReachable(A, B, &ExclusionSet, nullptr, LI),
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ExpectedResult);
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EXPECT_EQ(isPotentiallyReachable(A, B, &ExclusionSet, DT, LI),
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ExpectedResult);
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return false;
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}
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bool ExpectedResult;
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Instruction *A, *B;
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SmallPtrSet<BasicBlock *, 4> ExclusionSet;
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};
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static int initialize = IsPotentiallyReachableTestPass::initialize();
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(void)initialize;
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IsPotentiallyReachableTestPass *P =
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new IsPotentiallyReachableTestPass(ExpectedResult, A, B, ExclusionSet);
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legacy::PassManager PM;
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PM.add(P);
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PM.run(*M);
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}
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LLVMContext Context;
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std::unique_ptr<Module> M;
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Instruction *A, *B;
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SmallPtrSet<BasicBlock *, 4> ExclusionSet;
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};
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}
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TEST_F(IsPotentiallyReachableTest, SameBlockNoPath) {
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ParseAssembly(
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"define void @test() {\n"
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"entry:\n"
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" bitcast i8 undef to i8\n"
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" %B = bitcast i8 undef to i8\n"
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" bitcast i8 undef to i8\n"
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" bitcast i8 undef to i8\n"
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" %A = bitcast i8 undef to i8\n"
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" ret void\n"
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"}\n");
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ExpectPath(false);
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}
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TEST_F(IsPotentiallyReachableTest, SameBlockPath) {
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ParseAssembly(
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"define void @test() {\n"
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"entry:\n"
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" %A = bitcast i8 undef to i8\n"
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" bitcast i8 undef to i8\n"
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" bitcast i8 undef to i8\n"
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" %B = bitcast i8 undef to i8\n"
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" ret void\n"
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"}\n");
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ExpectPath(true);
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}
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TEST_F(IsPotentiallyReachableTest, SameBlockNoLoop) {
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ParseAssembly(
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"define void @test() {\n"
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"entry:\n"
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" br label %middle\n"
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"middle:\n"
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" %B = bitcast i8 undef to i8\n"
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" bitcast i8 undef to i8\n"
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" bitcast i8 undef to i8\n"
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" %A = bitcast i8 undef to i8\n"
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" br label %nextblock\n"
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"nextblock:\n"
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" ret void\n"
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"}\n");
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ExpectPath(false);
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}
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TEST_F(IsPotentiallyReachableTest, StraightNoPath) {
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ParseAssembly(
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"define void @test() {\n"
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"entry:\n"
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" %B = bitcast i8 undef to i8\n"
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" br label %exit\n"
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"exit:\n"
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" %A = bitcast i8 undef to i8\n"
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" ret void\n"
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"}");
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ExpectPath(false);
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}
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TEST_F(IsPotentiallyReachableTest, StraightPath) {
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ParseAssembly(
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"define void @test() {\n"
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"entry:\n"
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" %A = bitcast i8 undef to i8\n"
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" br label %exit\n"
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"exit:\n"
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" %B = bitcast i8 undef to i8\n"
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" ret void\n"
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"}");
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ExpectPath(true);
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}
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TEST_F(IsPotentiallyReachableTest, DestUnreachable) {
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ParseAssembly(
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"define void @test() {\n"
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"entry:\n"
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" br label %midblock\n"
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"midblock:\n"
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" %A = bitcast i8 undef to i8\n"
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" ret void\n"
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"unreachable:\n"
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" %B = bitcast i8 undef to i8\n"
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" br label %midblock\n"
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"}");
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ExpectPath(false);
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}
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TEST_F(IsPotentiallyReachableTest, BranchToReturn) {
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ParseAssembly(
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"define void @test(i1 %x) {\n"
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"entry:\n"
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" %A = bitcast i8 undef to i8\n"
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" br i1 %x, label %block1, label %block2\n"
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"block1:\n"
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" ret void\n"
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"block2:\n"
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" %B = bitcast i8 undef to i8\n"
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" ret void\n"
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"}");
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ExpectPath(true);
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}
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TEST_F(IsPotentiallyReachableTest, SimpleLoop1) {
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ParseAssembly(
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"declare i1 @switch()\n"
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"\n"
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"define void @test() {\n"
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"entry:\n"
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" br label %loop\n"
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"loop:\n"
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" %B = bitcast i8 undef to i8\n"
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" %A = bitcast i8 undef to i8\n"
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" %x = call i1 @switch()\n"
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" br i1 %x, label %loop, label %exit\n"
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"exit:\n"
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" ret void\n"
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"}");
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ExpectPath(true);
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}
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TEST_F(IsPotentiallyReachableTest, SimpleLoop2) {
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ParseAssembly(
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"declare i1 @switch()\n"
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"\n"
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"define void @test() {\n"
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"entry:\n"
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" %B = bitcast i8 undef to i8\n"
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" br label %loop\n"
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"loop:\n"
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" %A = bitcast i8 undef to i8\n"
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" %x = call i1 @switch()\n"
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" br i1 %x, label %loop, label %exit\n"
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"exit:\n"
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" ret void\n"
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"}");
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ExpectPath(false);
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}
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TEST_F(IsPotentiallyReachableTest, SimpleLoop3) {
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ParseAssembly(
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"declare i1 @switch()\n"
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"\n"
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"define void @test() {\n"
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"entry:\n"
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" br label %loop\n"
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"loop:\n"
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" %B = bitcast i8 undef to i8\n"
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" %x = call i1 @switch()\n"
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" br i1 %x, label %loop, label %exit\n"
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"exit:\n"
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" %A = bitcast i8 undef to i8\n"
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" ret void\n"
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"}");
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ExpectPath(false);
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}
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TEST_F(IsPotentiallyReachableTest, OneLoopAfterTheOther1) {
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ParseAssembly(
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"declare i1 @switch()\n"
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"\n"
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"define void @test() {\n"
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"entry:\n"
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" br label %loop1\n"
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"loop1:\n"
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" %A = bitcast i8 undef to i8\n"
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" %x = call i1 @switch()\n"
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" br i1 %x, label %loop1, label %loop1exit\n"
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"loop1exit:\n"
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" br label %loop2\n"
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"loop2:\n"
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" %B = bitcast i8 undef to i8\n"
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" %y = call i1 @switch()\n"
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" br i1 %x, label %loop2, label %loop2exit\n"
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"loop2exit:"
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" ret void\n"
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"}");
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ExpectPath(true);
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}
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TEST_F(IsPotentiallyReachableTest, OneLoopAfterTheOther2) {
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ParseAssembly(
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"declare i1 @switch()\n"
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"\n"
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"define void @test() {\n"
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"entry:\n"
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" br label %loop1\n"
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"loop1:\n"
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" %B = bitcast i8 undef to i8\n"
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" %x = call i1 @switch()\n"
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" br i1 %x, label %loop1, label %loop1exit\n"
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"loop1exit:\n"
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" br label %loop2\n"
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"loop2:\n"
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" %A = bitcast i8 undef to i8\n"
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" %y = call i1 @switch()\n"
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" br i1 %x, label %loop2, label %loop2exit\n"
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"loop2exit:"
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" ret void\n"
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"}");
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ExpectPath(false);
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}
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TEST_F(IsPotentiallyReachableTest, OneLoopAfterTheOtherInsideAThirdLoop) {
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ParseAssembly(
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"declare i1 @switch()\n"
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"\n"
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"define void @test() {\n"
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"entry:\n"
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" br label %outerloop3\n"
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"outerloop3:\n"
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" br label %innerloop1\n"
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"innerloop1:\n"
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" %B = bitcast i8 undef to i8\n"
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" %x = call i1 @switch()\n"
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" br i1 %x, label %innerloop1, label %innerloop1exit\n"
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"innerloop1exit:\n"
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" br label %innerloop2\n"
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"innerloop2:\n"
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" %A = bitcast i8 undef to i8\n"
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" %y = call i1 @switch()\n"
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" br i1 %x, label %innerloop2, label %innerloop2exit\n"
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"innerloop2exit:"
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" ;; In outer loop3 now.\n"
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" %z = call i1 @switch()\n"
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" br i1 %z, label %outerloop3, label %exit\n"
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"exit:\n"
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" ret void\n"
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"}");
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ExpectPath(true);
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}
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static const char *BranchInsideLoopIR =
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"declare i1 @switch()\n"
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"\n"
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"define void @test() {\n"
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"entry:\n"
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" br label %loop\n"
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"loop:\n"
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" %x = call i1 @switch()\n"
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" br i1 %x, label %nextloopblock, label %exit\n"
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"nextloopblock:\n"
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" %y = call i1 @switch()\n"
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" br i1 %y, label %left, label %right\n"
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"left:\n"
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" %A = bitcast i8 undef to i8\n"
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" br label %loop\n"
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"right:\n"
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" %B = bitcast i8 undef to i8\n"
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" br label %loop\n"
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"exit:\n"
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" ret void\n"
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"}";
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TEST_F(IsPotentiallyReachableTest, BranchInsideLoop) {
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ParseAssembly(BranchInsideLoopIR);
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ExpectPath(true);
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}
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TEST_F(IsPotentiallyReachableTest, ModifyTest) {
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ParseAssembly(BranchInsideLoopIR);
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succ_iterator S = succ_begin(&*++M->getFunction("test")->begin());
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BasicBlock *OldBB = S[0];
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S[0] = S[1];
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ExpectPath(false);
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S[0] = OldBB;
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ExpectPath(true);
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}
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TEST_F(IsPotentiallyReachableTest, UnreachableFromEntryTest) {
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ParseAssembly("define void @test() {\n"
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"entry:\n"
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" %A = bitcast i8 undef to i8\n"
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" ret void\n"
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"not.reachable:\n"
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" %B = bitcast i8 undef to i8\n"
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" ret void\n"
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"}");
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ExpectPath(false);
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}
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TEST_F(IsPotentiallyReachableTest, UnreachableBlocksTest1) {
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ParseAssembly("define void @test() {\n"
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"entry:\n"
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" ret void\n"
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"not.reachable.1:\n"
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" %A = bitcast i8 undef to i8\n"
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" br label %not.reachable.2\n"
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"not.reachable.2:\n"
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" %B = bitcast i8 undef to i8\n"
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" ret void\n"
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"}");
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ExpectPath(true);
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}
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TEST_F(IsPotentiallyReachableTest, UnreachableBlocksTest2) {
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ParseAssembly("define void @test() {\n"
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"entry:\n"
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" ret void\n"
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"not.reachable.1:\n"
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" %B = bitcast i8 undef to i8\n"
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" br label %not.reachable.2\n"
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"not.reachable.2:\n"
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" %A = bitcast i8 undef to i8\n"
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" ret void\n"
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"}");
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ExpectPath(false);
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}
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TEST_F(IsPotentiallyReachableTest, SimpleExclusionTest) {
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ParseAssembly("define void @test() {\n"
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"entry:\n"
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" %A = bitcast i8 undef to i8\n"
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" br label %excluded\n"
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"excluded:\n"
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" br label %exit\n"
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"exit:\n"
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" %B = bitcast i8 undef to i8\n"
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" ret void\n"
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"}");
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ExpectPath(false);
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}
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TEST_F(IsPotentiallyReachableTest, DiamondExcludedTest) {
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ParseAssembly("declare i1 @switch()\n"
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"\n"
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"define void @test() {\n"
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"entry:\n"
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" %x = call i1 @switch()\n"
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" %A = bitcast i8 undef to i8\n"
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" br i1 %x, label %excluded.1, label %excluded.2\n"
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"excluded.1:\n"
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" br label %exit\n"
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"excluded.2:\n"
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" br label %exit\n"
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"exit:\n"
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" %B = bitcast i8 undef to i8\n"
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" ret void\n"
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"}");
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ExpectPath(false);
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}
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TEST_F(IsPotentiallyReachableTest, DiamondOneSideExcludedTest) {
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ParseAssembly("declare i1 @switch()\n"
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"\n"
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"define void @test() {\n"
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"entry:\n"
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" %x = call i1 @switch()\n"
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" %A = bitcast i8 undef to i8\n"
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" br i1 %x, label %excluded, label %diamond\n"
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"excluded:\n"
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" br label %exit\n"
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"diamond:\n"
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" br label %exit\n"
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"exit:\n"
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" %B = bitcast i8 undef to i8\n"
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" ret void\n"
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"}");
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ExpectPath(true);
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}
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TEST_F(IsPotentiallyReachableTest, UnreachableToReachable) {
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ParseAssembly("define void @test() {\n"
|
|
"entry:\n"
|
|
" br label %exit\n"
|
|
"unreachableblock:\n"
|
|
" %A = bitcast i8 undef to i8\n"
|
|
" br label %exit\n"
|
|
"exit:\n"
|
|
" %B = bitcast i8 undef to i8\n"
|
|
" ret void\n"
|
|
"}");
|
|
ExpectPath(true);
|
|
}
|