llvm-project/llvm/unittests/IR/DominatorTreeTest.cpp

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//===- llvm/unittests/IR/DominatorTreeTest.cpp - Constants unit 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/PostDominators.h"
#include "llvm/AsmParser/Parser.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/SourceMgr.h"
#include "CFGBuilder.h"
#include "gtest/gtest.h"
using namespace llvm;
struct PostDomTree : PostDomTreeBase<BasicBlock> {
PostDomTree(Function &F) { recalculate(F); }
};
/// Build the dominator tree for the function and run the Test.
static void runWithDomTree(
Module &M, StringRef FuncName,
function_ref<void(Function &F, DominatorTree *DT, PostDomTree *PDT)> Test) {
auto *F = M.getFunction(FuncName);
ASSERT_NE(F, nullptr) << "Could not find " << FuncName;
// Compute the dominator tree for the function.
DominatorTree DT(*F);
PostDomTree PDT(*F);
Test(*F, &DT, &PDT);
}
static std::unique_ptr<Module> makeLLVMModule(LLVMContext &Context,
StringRef ModuleStr) {
SMDiagnostic Err;
std::unique_ptr<Module> M = parseAssemblyString(ModuleStr, Err, Context);
assert(M && "Bad assembly?");
return M;
}
TEST(DominatorTree, Unreachable) {
StringRef ModuleString =
"declare i32 @g()\n"
"define void @f(i32 %x) personality i32 ()* @g {\n"
"bb0:\n"
" %y1 = add i32 %x, 1\n"
" %y2 = add i32 %x, 1\n"
" %y3 = invoke i32 @g() to label %bb1 unwind label %bb2\n"
"bb1:\n"
" %y4 = add i32 %x, 1\n"
" br label %bb4\n"
"bb2:\n"
" %y5 = landingpad i32\n"
" cleanup\n"
" br label %bb4\n"
"bb3:\n"
" %y6 = add i32 %x, 1\n"
" %y7 = add i32 %x, 1\n"
" ret void\n"
"bb4:\n"
" %y8 = phi i32 [0, %bb2], [%y4, %bb1]\n"
" %y9 = phi i32 [0, %bb2], [%y4, %bb1]\n"
" ret void\n"
"}\n";
// Parse the module.
LLVMContext Context;
std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
runWithDomTree(
*M, "f", [&](Function &F, DominatorTree *DT, PostDomTree *PDT) {
Function::iterator FI = F.begin();
BasicBlock *BB0 = &*FI++;
BasicBlock::iterator BBI = BB0->begin();
Instruction *Y1 = &*BBI++;
Instruction *Y2 = &*BBI++;
Instruction *Y3 = &*BBI++;
BasicBlock *BB1 = &*FI++;
BBI = BB1->begin();
Instruction *Y4 = &*BBI++;
BasicBlock *BB2 = &*FI++;
BBI = BB2->begin();
Instruction *Y5 = &*BBI++;
BasicBlock *BB3 = &*FI++;
BBI = BB3->begin();
Instruction *Y6 = &*BBI++;
Instruction *Y7 = &*BBI++;
BasicBlock *BB4 = &*FI++;
BBI = BB4->begin();
Instruction *Y8 = &*BBI++;
Instruction *Y9 = &*BBI++;
// Reachability
EXPECT_TRUE(DT->isReachableFromEntry(BB0));
EXPECT_TRUE(DT->isReachableFromEntry(BB1));
EXPECT_TRUE(DT->isReachableFromEntry(BB2));
EXPECT_FALSE(DT->isReachableFromEntry(BB3));
EXPECT_TRUE(DT->isReachableFromEntry(BB4));
// BB dominance
EXPECT_TRUE(DT->dominates(BB0, BB0));
EXPECT_TRUE(DT->dominates(BB0, BB1));
EXPECT_TRUE(DT->dominates(BB0, BB2));
EXPECT_TRUE(DT->dominates(BB0, BB3));
EXPECT_TRUE(DT->dominates(BB0, BB4));
EXPECT_FALSE(DT->dominates(BB1, BB0));
EXPECT_TRUE(DT->dominates(BB1, BB1));
EXPECT_FALSE(DT->dominates(BB1, BB2));
EXPECT_TRUE(DT->dominates(BB1, BB3));
EXPECT_FALSE(DT->dominates(BB1, BB4));
EXPECT_FALSE(DT->dominates(BB2, BB0));
EXPECT_FALSE(DT->dominates(BB2, BB1));
EXPECT_TRUE(DT->dominates(BB2, BB2));
EXPECT_TRUE(DT->dominates(BB2, BB3));
EXPECT_FALSE(DT->dominates(BB2, BB4));
EXPECT_FALSE(DT->dominates(BB3, BB0));
EXPECT_FALSE(DT->dominates(BB3, BB1));
EXPECT_FALSE(DT->dominates(BB3, BB2));
EXPECT_TRUE(DT->dominates(BB3, BB3));
EXPECT_FALSE(DT->dominates(BB3, BB4));
// BB proper dominance
EXPECT_FALSE(DT->properlyDominates(BB0, BB0));
EXPECT_TRUE(DT->properlyDominates(BB0, BB1));
EXPECT_TRUE(DT->properlyDominates(BB0, BB2));
EXPECT_TRUE(DT->properlyDominates(BB0, BB3));
EXPECT_FALSE(DT->properlyDominates(BB1, BB0));
EXPECT_FALSE(DT->properlyDominates(BB1, BB1));
EXPECT_FALSE(DT->properlyDominates(BB1, BB2));
EXPECT_TRUE(DT->properlyDominates(BB1, BB3));
EXPECT_FALSE(DT->properlyDominates(BB2, BB0));
EXPECT_FALSE(DT->properlyDominates(BB2, BB1));
EXPECT_FALSE(DT->properlyDominates(BB2, BB2));
EXPECT_TRUE(DT->properlyDominates(BB2, BB3));
EXPECT_FALSE(DT->properlyDominates(BB3, BB0));
EXPECT_FALSE(DT->properlyDominates(BB3, BB1));
EXPECT_FALSE(DT->properlyDominates(BB3, BB2));
EXPECT_FALSE(DT->properlyDominates(BB3, BB3));
// Instruction dominance in the same reachable BB
EXPECT_FALSE(DT->dominates(Y1, Y1));
EXPECT_TRUE(DT->dominates(Y1, Y2));
EXPECT_FALSE(DT->dominates(Y2, Y1));
EXPECT_FALSE(DT->dominates(Y2, Y2));
// Instruction dominance in the same unreachable BB
EXPECT_TRUE(DT->dominates(Y6, Y6));
EXPECT_TRUE(DT->dominates(Y6, Y7));
EXPECT_TRUE(DT->dominates(Y7, Y6));
EXPECT_TRUE(DT->dominates(Y7, Y7));
// Invoke
EXPECT_TRUE(DT->dominates(Y3, Y4));
EXPECT_FALSE(DT->dominates(Y3, Y5));
// Phi
EXPECT_TRUE(DT->dominates(Y2, Y9));
EXPECT_FALSE(DT->dominates(Y3, Y9));
EXPECT_FALSE(DT->dominates(Y8, Y9));
// Anything dominates unreachable
EXPECT_TRUE(DT->dominates(Y1, Y6));
EXPECT_TRUE(DT->dominates(Y3, Y6));
// Unreachable doesn't dominate reachable
EXPECT_FALSE(DT->dominates(Y6, Y1));
// Instruction, BB dominance
EXPECT_FALSE(DT->dominates(Y1, BB0));
EXPECT_TRUE(DT->dominates(Y1, BB1));
EXPECT_TRUE(DT->dominates(Y1, BB2));
EXPECT_TRUE(DT->dominates(Y1, BB3));
EXPECT_TRUE(DT->dominates(Y1, BB4));
EXPECT_FALSE(DT->dominates(Y3, BB0));
EXPECT_TRUE(DT->dominates(Y3, BB1));
EXPECT_FALSE(DT->dominates(Y3, BB2));
EXPECT_TRUE(DT->dominates(Y3, BB3));
EXPECT_FALSE(DT->dominates(Y3, BB4));
EXPECT_TRUE(DT->dominates(Y6, BB3));
// Post dominance.
EXPECT_TRUE(PDT->dominates(BB0, BB0));
EXPECT_FALSE(PDT->dominates(BB1, BB0));
EXPECT_FALSE(PDT->dominates(BB2, BB0));
EXPECT_FALSE(PDT->dominates(BB3, BB0));
EXPECT_TRUE(PDT->dominates(BB4, BB1));
// Dominance descendants.
SmallVector<BasicBlock *, 8> DominatedBBs, PostDominatedBBs;
DT->getDescendants(BB0, DominatedBBs);
PDT->getDescendants(BB0, PostDominatedBBs);
EXPECT_EQ(DominatedBBs.size(), 4UL);
EXPECT_EQ(PostDominatedBBs.size(), 1UL);
// BB3 is unreachable. It should have no dominators nor postdominators.
DominatedBBs.clear();
PostDominatedBBs.clear();
DT->getDescendants(BB3, DominatedBBs);
DT->getDescendants(BB3, PostDominatedBBs);
EXPECT_EQ(DominatedBBs.size(), 0UL);
EXPECT_EQ(PostDominatedBBs.size(), 0UL);
// Check DFS Numbers before
DT->updateDFSNumbers();
EXPECT_EQ(DT->getNode(BB0)->getDFSNumIn(), 0UL);
EXPECT_EQ(DT->getNode(BB0)->getDFSNumOut(), 7UL);
EXPECT_EQ(DT->getNode(BB1)->getDFSNumIn(), 1UL);
EXPECT_EQ(DT->getNode(BB1)->getDFSNumOut(), 2UL);
EXPECT_EQ(DT->getNode(BB2)->getDFSNumIn(), 5UL);
EXPECT_EQ(DT->getNode(BB2)->getDFSNumOut(), 6UL);
EXPECT_EQ(DT->getNode(BB4)->getDFSNumIn(), 3UL);
EXPECT_EQ(DT->getNode(BB4)->getDFSNumOut(), 4UL);
// Check levels before
EXPECT_EQ(DT->getNode(BB0)->getLevel(), 0U);
EXPECT_EQ(DT->getNode(BB1)->getLevel(), 1U);
EXPECT_EQ(DT->getNode(BB2)->getLevel(), 1U);
EXPECT_EQ(DT->getNode(BB4)->getLevel(), 1U);
// Reattach block 3 to block 1 and recalculate
BB1->getTerminator()->eraseFromParent();
BranchInst::Create(BB4, BB3, ConstantInt::getTrue(F.getContext()), BB1);
DT->recalculate(F);
// Check DFS Numbers after
DT->updateDFSNumbers();
EXPECT_EQ(DT->getNode(BB0)->getDFSNumIn(), 0UL);
EXPECT_EQ(DT->getNode(BB0)->getDFSNumOut(), 9UL);
EXPECT_EQ(DT->getNode(BB1)->getDFSNumIn(), 1UL);
EXPECT_EQ(DT->getNode(BB1)->getDFSNumOut(), 4UL);
EXPECT_EQ(DT->getNode(BB2)->getDFSNumIn(), 7UL);
EXPECT_EQ(DT->getNode(BB2)->getDFSNumOut(), 8UL);
EXPECT_EQ(DT->getNode(BB3)->getDFSNumIn(), 2UL);
EXPECT_EQ(DT->getNode(BB3)->getDFSNumOut(), 3UL);
EXPECT_EQ(DT->getNode(BB4)->getDFSNumIn(), 5UL);
EXPECT_EQ(DT->getNode(BB4)->getDFSNumOut(), 6UL);
// Check levels after
EXPECT_EQ(DT->getNode(BB0)->getLevel(), 0U);
EXPECT_EQ(DT->getNode(BB1)->getLevel(), 1U);
EXPECT_EQ(DT->getNode(BB2)->getLevel(), 1U);
EXPECT_EQ(DT->getNode(BB3)->getLevel(), 2U);
EXPECT_EQ(DT->getNode(BB4)->getLevel(), 1U);
// Change root node
DT->verifyDomTree();
BasicBlock *NewEntry =
BasicBlock::Create(F.getContext(), "new_entry", &F, BB0);
BranchInst::Create(BB0, NewEntry);
EXPECT_EQ(F.begin()->getName(), NewEntry->getName());
EXPECT_TRUE(&F.getEntryBlock() == NewEntry);
DT->setNewRoot(NewEntry);
DT->verifyDomTree();
});
}
TEST(DominatorTree, NonUniqueEdges) {
StringRef ModuleString =
"define i32 @f(i32 %i, i32 *%p) {\n"
"bb0:\n"
" store i32 %i, i32 *%p\n"
" switch i32 %i, label %bb2 [\n"
" i32 0, label %bb1\n"
" i32 1, label %bb1\n"
" ]\n"
" bb1:\n"
" ret i32 1\n"
" bb2:\n"
" ret i32 4\n"
"}\n";
// Parse the module.
LLVMContext Context;
std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
runWithDomTree(
*M, "f", [&](Function &F, DominatorTree *DT, PostDomTree *PDT) {
Function::iterator FI = F.begin();
BasicBlock *BB0 = &*FI++;
BasicBlock *BB1 = &*FI++;
BasicBlock *BB2 = &*FI++;
const TerminatorInst *TI = BB0->getTerminator();
assert(TI->getNumSuccessors() == 3 && "Switch has three successors");
BasicBlockEdge Edge_BB0_BB2(BB0, TI->getSuccessor(0));
assert(Edge_BB0_BB2.getEnd() == BB2 &&
"Default label is the 1st successor");
BasicBlockEdge Edge_BB0_BB1_a(BB0, TI->getSuccessor(1));
assert(Edge_BB0_BB1_a.getEnd() == BB1 && "BB1 is the 2nd successor");
BasicBlockEdge Edge_BB0_BB1_b(BB0, TI->getSuccessor(2));
assert(Edge_BB0_BB1_b.getEnd() == BB1 && "BB1 is the 3rd successor");
EXPECT_TRUE(DT->dominates(Edge_BB0_BB2, BB2));
EXPECT_FALSE(DT->dominates(Edge_BB0_BB2, BB1));
EXPECT_FALSE(DT->dominates(Edge_BB0_BB1_a, BB1));
EXPECT_FALSE(DT->dominates(Edge_BB0_BB1_b, BB1));
EXPECT_FALSE(DT->dominates(Edge_BB0_BB1_a, BB2));
EXPECT_FALSE(DT->dominates(Edge_BB0_BB1_b, BB2));
});
}
namespace {
const auto Insert = CFGBuilder::ActionKind::Insert;
bool CompUpdates(const CFGBuilder::Update &A, const CFGBuilder::Update &B) {
return std::tie(A.Action, A.Edge.From, A.Edge.To) <
std::tie(B.Action, B.Edge.From, B.Edge.To);
};
} // namespace
TEST(DominatorTree, InsertReachable) {
CFGHolder Holder;
std::vector<CFGBuilder::Arc> Arcs = {
{"1", "2"}, {"2", "3"}, {"3", "4"}, {"4", "5"}, {"5", "6"}, {"5", "7"},
{"3", "8"}, {"8", "9"}, {"9", "10"}, {"8", "11"}, {"11", "12"}};
std::vector<CFGBuilder::Update> Updates = {{Insert, {"12", "10"}},
{Insert, {"10", "9"}},
{Insert, {"7", "6"}},
{Insert, {"7", "5"}}};
CFGBuilder B(Holder.F, Arcs, Updates);
DominatorTree DT(*Holder.F);
EXPECT_TRUE(DT.verify());
PostDomTree PDT(*Holder.F);
EXPECT_TRUE(PDT.verify());
Optional<CFGBuilder::Update> LastUpdate;
while ((LastUpdate = B.applyUpdate())) {
EXPECT_EQ(LastUpdate->Action, Insert);
BasicBlock *From = B.getOrAddBlock(LastUpdate->Edge.From);
BasicBlock *To = B.getOrAddBlock(LastUpdate->Edge.To);
DT.insertEdge(From, To);
EXPECT_TRUE(DT.verify());
PDT.insertEdge(From, To);
EXPECT_TRUE(PDT.verify());
}
}
TEST(DominatorTree, InsertUnreachable) {
CFGHolder Holder;
std::vector<CFGBuilder::Arc> Arcs = {{"1", "2"}, {"2", "3"}, {"3", "4"},
{"5", "6"}, {"5", "7"}, {"3", "8"},
{"9", "10"}, {"11", "12"}};
std::vector<CFGBuilder::Update> Updates = {{Insert, {"4", "5"}},
{Insert, {"8", "9"}},
{Insert, {"10", "12"}},
{Insert, {"10", "11"}}};
CFGBuilder B(Holder.F, Arcs, Updates);
DominatorTree DT(*Holder.F);
EXPECT_TRUE(DT.verify());
PostDomTree PDT(*Holder.F);
EXPECT_TRUE(PDT.verify());
Optional<CFGBuilder::Update> LastUpdate;
while ((LastUpdate = B.applyUpdate())) {
EXPECT_EQ(LastUpdate->Action, Insert);
BasicBlock *From = B.getOrAddBlock(LastUpdate->Edge.From);
BasicBlock *To = B.getOrAddBlock(LastUpdate->Edge.To);
DT.insertEdge(From, To);
EXPECT_TRUE(DT.verify());
PDT.insertEdge(From, To);
EXPECT_TRUE(PDT.verify());
}
}
TEST(DominatorTree, InsertMixed) {
CFGHolder Holder;
std::vector<CFGBuilder::Arc> Arcs = {
{"1", "2"}, {"2", "3"}, {"3", "4"}, {"5", "6"}, {"5", "7"},
{"8", "9"}, {"9", "10"}, {"8", "11"}, {"11", "12"}, {"7", "3"}};
std::vector<CFGBuilder::Update> Updates = {
{Insert, {"4", "5"}}, {Insert, {"2", "5"}}, {Insert, {"10", "9"}},
{Insert, {"12", "10"}}, {Insert, {"12", "10"}}, {Insert, {"7", "8"}},
{Insert, {"7", "5"}}};
CFGBuilder B(Holder.F, Arcs, Updates);
DominatorTree DT(*Holder.F);
EXPECT_TRUE(DT.verify());
PostDomTree PDT(*Holder.F);
EXPECT_TRUE(PDT.verify());
Optional<CFGBuilder::Update> LastUpdate;
while ((LastUpdate = B.applyUpdate())) {
EXPECT_EQ(LastUpdate->Action, Insert);
BasicBlock *From = B.getOrAddBlock(LastUpdate->Edge.From);
BasicBlock *To = B.getOrAddBlock(LastUpdate->Edge.To);
DT.insertEdge(From, To);
EXPECT_TRUE(DT.verify());
PDT.insertEdge(From, To);
EXPECT_TRUE(PDT.verify());
}
}
TEST(DominatorTree, InsertPermut) {
std::vector<CFGBuilder::Arc> Arcs = {
{"1", "2"}, {"2", "3"}, {"3", "4"}, {"5", "6"}, {"5", "7"},
{"8", "9"}, {"9", "10"}, {"8", "11"}, {"11", "12"}, {"7", "3"}};
std::vector<CFGBuilder::Update> Updates = {{Insert, {"4", "5"}},
{Insert, {"2", "5"}},
{Insert, {"10", "9"}},
{Insert, {"12", "10"}}};
while (std::next_permutation(Updates.begin(), Updates.end(), CompUpdates)) {
CFGHolder Holder;
CFGBuilder B(Holder.F, Arcs, Updates);
DominatorTree DT(*Holder.F);
EXPECT_TRUE(DT.verify());
PostDomTree PDT(*Holder.F);
EXPECT_TRUE(PDT.verify());
Optional<CFGBuilder::Update> LastUpdate;
while ((LastUpdate = B.applyUpdate())) {
EXPECT_EQ(LastUpdate->Action, Insert);
BasicBlock *From = B.getOrAddBlock(LastUpdate->Edge.From);
BasicBlock *To = B.getOrAddBlock(LastUpdate->Edge.To);
DT.insertEdge(From, To);
EXPECT_TRUE(DT.verify());
PDT.insertEdge(From, To);
EXPECT_TRUE(PDT.verify());
}
}
}