llvm/unittests/Analysis/CFGTest.cpp
Nick Lewycky 72dba254ae Fix an oversight in isPotentiallyReachable where we wouldn't do any CFG-walking
to find loops if the From and To instructions were in the same block.

Refactor the code a little now that we need to fill to start the CFG-walking
algorithm with more than one starting basic block sometimes.

Special thanks to Andrew Trick for catching an error in my understanding of
natural loops in code review.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188236 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-13 00:03:47 +00:00

377 lines
10 KiB
C++

//===- CFGTest.cpp - CFG tests --------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/CFG.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Assembly/Parser.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/InstIterator.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Pass.h"
#include "llvm/PassManager.h"
#include "gtest/gtest.h"
using namespace llvm;
namespace {
// This fixture assists in running the isPotentiallyReachable utility four ways
// and ensuring it produces the correct answer each time.
class IsPotentiallyReachableTest : public testing::Test {
protected:
void ParseAssembly(const char *Assembly) {
M.reset(new Module("Module", getGlobalContext()));
SMDiagnostic Error;
bool Parsed = ParseAssemblyString(Assembly, M.get(),
Error, M->getContext()) == M.get();
std::string errMsg;
raw_string_ostream os(errMsg);
Error.print("", os);
if (!Parsed) {
// A failure here means that the test itself is buggy.
report_fatal_error(os.str().c_str());
}
Function *F = M->getFunction("test");
if (F == NULL)
report_fatal_error("Test must have a function named @test");
A = B = NULL;
for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
if (I->hasName()) {
if (I->getName() == "A")
A = &*I;
else if (I->getName() == "B")
B = &*I;
}
}
if (A == NULL)
report_fatal_error("@test must have an instruction %A");
if (B == NULL)
report_fatal_error("@test must have an instruction %B");
}
void ExpectPath(bool ExpectedResult) {
static char ID;
class IsPotentiallyReachableTestPass : public FunctionPass {
public:
IsPotentiallyReachableTestPass(bool ExpectedResult,
Instruction *A, Instruction *B)
: FunctionPass(ID), ExpectedResult(ExpectedResult), A(A), B(B) {}
static int initialize() {
PassInfo *PI = new PassInfo("isPotentiallyReachable testing pass",
"", &ID, 0, true, true);
PassRegistry::getPassRegistry()->registerPass(*PI, false);
initializeLoopInfoPass(*PassRegistry::getPassRegistry());
initializeDominatorTreePass(*PassRegistry::getPassRegistry());
return 0;
}
void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<LoopInfo>();
AU.addRequired<DominatorTree>();
}
bool runOnFunction(Function &F) {
if (!F.hasName() || F.getName() != "test")
return false;
LoopInfo *LI = &getAnalysis<LoopInfo>();
DominatorTree *DT = &getAnalysis<DominatorTree>();
EXPECT_EQ(isPotentiallyReachable(A, B, 0, 0), ExpectedResult);
EXPECT_EQ(isPotentiallyReachable(A, B, DT, 0), ExpectedResult);
EXPECT_EQ(isPotentiallyReachable(A, B, 0, LI), ExpectedResult);
EXPECT_EQ(isPotentiallyReachable(A, B, DT, LI), ExpectedResult);
return false;
}
bool ExpectedResult;
Instruction *A, *B;
};
static int initialize = IsPotentiallyReachableTestPass::initialize();
(void)initialize;
IsPotentiallyReachableTestPass *P =
new IsPotentiallyReachableTestPass(ExpectedResult, A, B);
PassManager PM;
PM.add(P);
PM.run(*M);
}
private:
OwningPtr<Module> M;
Instruction *A, *B;
};
}
TEST_F(IsPotentiallyReachableTest, SameBlockNoPath) {
ParseAssembly(
"define void @test() {\n"
"entry:\n"
" bitcast i8 undef to i8\n"
" %B = bitcast i8 undef to i8\n"
" bitcast i8 undef to i8\n"
" bitcast i8 undef to i8\n"
" %A = bitcast i8 undef to i8\n"
" ret void\n"
"}\n");
ExpectPath(false);
}
TEST_F(IsPotentiallyReachableTest, SameBlockPath) {
ParseAssembly(
"define void @test() {\n"
"entry:\n"
" %A = bitcast i8 undef to i8\n"
" bitcast i8 undef to i8\n"
" bitcast i8 undef to i8\n"
" %B = bitcast i8 undef to i8\n"
" ret void\n"
"}\n");
ExpectPath(true);
}
TEST_F(IsPotentiallyReachableTest, SameBlockNoLoop) {
ParseAssembly(
"define void @test() {\n"
"entry:\n"
" br label %middle\n"
"middle:\n"
" %B = bitcast i8 undef to i8\n"
" bitcast i8 undef to i8\n"
" bitcast i8 undef to i8\n"
" %A = bitcast i8 undef to i8\n"
" br label %nextblock\n"
"nextblock:\n"
" ret void\n"
"}\n");
ExpectPath(false);
}
TEST_F(IsPotentiallyReachableTest, StraightNoPath) {
ParseAssembly(
"define void @test() {\n"
"entry:\n"
" %B = bitcast i8 undef to i8\n"
" br label %exit\n"
"exit:\n"
" %A = bitcast i8 undef to i8\n"
" ret void\n"
"}");
ExpectPath(false);
}
TEST_F(IsPotentiallyReachableTest, StraightPath) {
ParseAssembly(
"define void @test() {\n"
"entry:\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);
}
TEST_F(IsPotentiallyReachableTest, DestUnreachable) {
ParseAssembly(
"define void @test() {\n"
"entry:\n"
" br label %midblock\n"
"midblock:\n"
" %A = bitcast i8 undef to i8\n"
" ret void\n"
"unreachable:\n"
" %B = bitcast i8 undef to i8\n"
" br label %midblock\n"
"}");
ExpectPath(false);
}
TEST_F(IsPotentiallyReachableTest, BranchToReturn) {
ParseAssembly(
"define void @test(i1 %x) {\n"
"entry:\n"
" %A = bitcast i8 undef to i8\n"
" br i1 %x, label %block1, label %block2\n"
"block1:\n"
" ret void\n"
"block2:\n"
" %B = bitcast i8 undef to i8\n"
" ret void\n"
"}");
ExpectPath(true);
}
TEST_F(IsPotentiallyReachableTest, SimpleLoop1) {
ParseAssembly(
"declare i1 @switch()\n"
"\n"
"define void @test() {\n"
"entry:\n"
" br label %loop\n"
"loop:\n"
" %B = bitcast i8 undef to i8\n"
" %A = bitcast i8 undef to i8\n"
" %x = call i1 @switch()\n"
" br i1 %x, label %loop, label %exit\n"
"exit:\n"
" ret void\n"
"}");
ExpectPath(true);
}
TEST_F(IsPotentiallyReachableTest, SimpleLoop2) {
ParseAssembly(
"declare i1 @switch()\n"
"\n"
"define void @test() {\n"
"entry:\n"
" %B = bitcast i8 undef to i8\n"
" br label %loop\n"
"loop:\n"
" %A = bitcast i8 undef to i8\n"
" %x = call i1 @switch()\n"
" br i1 %x, label %loop, label %exit\n"
"exit:\n"
" ret void\n"
"}");
ExpectPath(false);
}
TEST_F(IsPotentiallyReachableTest, SimpleLoop3) {
ParseAssembly(
"declare i1 @switch()\n"
"\n"
"define void @test() {\n"
"entry:\n"
" br label %loop\n"
"loop:\n"
" %B = bitcast i8 undef to i8\n"
" %x = call i1 @switch()\n"
" br i1 %x, label %loop, label %exit\n"
"exit:\n"
" %A = bitcast i8 undef to i8\n"
" ret void\n"
"}");
ExpectPath(false);
}
TEST_F(IsPotentiallyReachableTest, OneLoopAfterTheOther1) {
ParseAssembly(
"declare i1 @switch()\n"
"\n"
"define void @test() {\n"
"entry:\n"
" br label %loop1\n"
"loop1:\n"
" %A = bitcast i8 undef to i8\n"
" %x = call i1 @switch()\n"
" br i1 %x, label %loop1, label %loop1exit\n"
"loop1exit:\n"
" br label %loop2\n"
"loop2:\n"
" %B = bitcast i8 undef to i8\n"
" %y = call i1 @switch()\n"
" br i1 %x, label %loop2, label %loop2exit\n"
"loop2exit:"
" ret void\n"
"}");
ExpectPath(true);
}
TEST_F(IsPotentiallyReachableTest, OneLoopAfterTheOther2) {
ParseAssembly(
"declare i1 @switch()\n"
"\n"
"define void @test() {\n"
"entry:\n"
" br label %loop1\n"
"loop1:\n"
" %B = bitcast i8 undef to i8\n"
" %x = call i1 @switch()\n"
" br i1 %x, label %loop1, label %loop1exit\n"
"loop1exit:\n"
" br label %loop2\n"
"loop2:\n"
" %A = bitcast i8 undef to i8\n"
" %y = call i1 @switch()\n"
" br i1 %x, label %loop2, label %loop2exit\n"
"loop2exit:"
" ret void\n"
"}");
ExpectPath(false);
}
TEST_F(IsPotentiallyReachableTest, OneLoopAfterTheOtherInsideAThirdLoop) {
ParseAssembly(
"declare i1 @switch()\n"
"\n"
"define void @test() {\n"
"entry:\n"
" br label %outerloop3\n"
"outerloop3:\n"
" br label %innerloop1\n"
"innerloop1:\n"
" %B = bitcast i8 undef to i8\n"
" %x = call i1 @switch()\n"
" br i1 %x, label %innerloop1, label %innerloop1exit\n"
"innerloop1exit:\n"
" br label %innerloop2\n"
"innerloop2:\n"
" %A = bitcast i8 undef to i8\n"
" %y = call i1 @switch()\n"
" br i1 %x, label %innerloop2, label %innerloop2exit\n"
"innerloop2exit:"
" ;; In outer loop3 now.\n"
" %z = call i1 @switch()\n"
" br i1 %z, label %outerloop3, label %exit\n"
"exit:\n"
" ret void\n"
"}");
ExpectPath(true);
}
TEST_F(IsPotentiallyReachableTest, BranchInsideLoop) {
ParseAssembly(
"declare i1 @switch()\n"
"\n"
"define void @test() {\n"
"entry:\n"
" br label %loop\n"
"loop:\n"
" %x = call i1 @switch()\n"
" br i1 %x, label %nextloopblock, label %exit\n"
"nextloopblock:\n"
" %y = call i1 @switch()\n"
" br i1 %y, label %left, label %right\n"
"left:\n"
" %A = bitcast i8 undef to i8\n"
" br label %loop\n"
"right:\n"
" %B = bitcast i8 undef to i8\n"
" br label %loop\n"
"exit:\n"
" ret void\n"
"}");
ExpectPath(true);
}