1 //=======- CaptureTrackingTest.cpp - Unit test for the Capture Tracking ---===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "llvm/Analysis/CaptureTracking.h" 10 #include "llvm/AsmParser/Parser.h" 11 #include "llvm/IR/Dominators.h" 12 #include "llvm/IR/Instructions.h" 13 #include "llvm/IR/LLVMContext.h" 14 #include "llvm/IR/Module.h" 15 #include "llvm/Support/SourceMgr.h" 16 #include "gtest/gtest.h" 17 18 using namespace llvm; 19 20 TEST(CaptureTracking, MaxUsesToExplore) { 21 StringRef Assembly = R"( 22 ; Function Attrs: nounwind ssp uwtable 23 declare void @doesnt_capture(i8* nocapture, i8* nocapture, i8* nocapture, 24 i8* nocapture, i8* nocapture) 25 26 ; %arg has 5 uses 27 define void @test_few_uses(i8* %arg) { 28 call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg) 29 ret void 30 } 31 32 ; %arg has 50 uses 33 define void @test_many_uses(i8* %arg) { 34 call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg) 35 call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg) 36 call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg) 37 call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg) 38 call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg) 39 call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg) 40 call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg) 41 call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg) 42 call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg) 43 call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg) 44 ret void 45 } 46 )"; 47 48 LLVMContext Context; 49 SMDiagnostic Error; 50 auto M = parseAssemblyString(Assembly, Error, Context); 51 ASSERT_TRUE(M) << "Bad assembly?"; 52 53 auto Test = [&M](const char *FName, unsigned FalseMaxUsesLimit, 54 unsigned TrueMaxUsesLimit) { 55 Function *F = M->getFunction(FName); 56 ASSERT_NE(F, nullptr); 57 Value *Arg = &*F->arg_begin(); 58 ASSERT_NE(Arg, nullptr); 59 ASSERT_FALSE(PointerMayBeCaptured(Arg, true, true, FalseMaxUsesLimit)); 60 ASSERT_TRUE(PointerMayBeCaptured(Arg, true, true, TrueMaxUsesLimit)); 61 62 BasicBlock *EntryBB = &F->getEntryBlock(); 63 DominatorTree DT(*F); 64 65 Instruction *Ret = EntryBB->getTerminator(); 66 ASSERT_TRUE(isa<ReturnInst>(Ret)); 67 ASSERT_FALSE(PointerMayBeCapturedBefore(Arg, true, true, Ret, &DT, false, 68 FalseMaxUsesLimit)); 69 ASSERT_TRUE(PointerMayBeCapturedBefore(Arg, true, true, Ret, &DT, false, 70 TrueMaxUsesLimit)); 71 }; 72 73 Test("test_few_uses", 6, 4); 74 Test("test_many_uses", 50, 30); 75 } 76 77 struct CollectingCaptureTracker : public CaptureTracker { 78 SmallVector<const Use *, 4> Captures; 79 void tooManyUses() { } 80 bool captured(const Use *U) override { 81 Captures.push_back(U); 82 return false; 83 } 84 }; 85 86 TEST(CaptureTracking, MultipleUsesInSameInstruction) { 87 StringRef Assembly = R"( 88 declare void @call(i8*, i8*, i8*) 89 90 define void @test(i8* %arg, i8** %ptr) { 91 call void @call(i8* %arg, i8* nocapture %arg, i8* %arg) [ "bundle"(i8* %arg) ] 92 cmpxchg i8** %ptr, i8* %arg, i8* %arg acq_rel monotonic 93 icmp eq i8* %arg, %arg 94 ret void 95 } 96 )"; 97 98 LLVMContext Context; 99 SMDiagnostic Error; 100 auto M = parseAssemblyString(Assembly, Error, Context); 101 ASSERT_TRUE(M) << "Bad assembly?"; 102 103 Function *F = M->getFunction("test"); 104 Value *Arg = &*F->arg_begin(); 105 BasicBlock *BB = &F->getEntryBlock(); 106 Instruction *Call = &*BB->begin(); 107 Instruction *CmpXChg = Call->getNextNode(); 108 Instruction *ICmp = CmpXChg->getNextNode(); 109 110 CollectingCaptureTracker CT; 111 PointerMayBeCaptured(Arg, &CT); 112 EXPECT_EQ(7u, CT.Captures.size()); 113 // Call arg 1 114 EXPECT_EQ(Call, CT.Captures[0]->getUser()); 115 EXPECT_EQ(0u, CT.Captures[0]->getOperandNo()); 116 // Call arg 3 117 EXPECT_EQ(Call, CT.Captures[1]->getUser()); 118 EXPECT_EQ(2u, CT.Captures[1]->getOperandNo()); 119 // Operand bundle arg 120 EXPECT_EQ(Call, CT.Captures[2]->getUser()); 121 EXPECT_EQ(3u, CT.Captures[2]->getOperandNo()); 122 // Cmpxchg compare operand 123 EXPECT_EQ(CmpXChg, CT.Captures[3]->getUser()); 124 EXPECT_EQ(1u, CT.Captures[3]->getOperandNo()); 125 // Cmpxchg new value operand 126 EXPECT_EQ(CmpXChg, CT.Captures[4]->getUser()); 127 EXPECT_EQ(2u, CT.Captures[4]->getOperandNo()); 128 // ICmp first operand 129 EXPECT_EQ(ICmp, CT.Captures[5]->getUser()); 130 EXPECT_EQ(0u, CT.Captures[5]->getOperandNo()); 131 // ICmp second operand 132 EXPECT_EQ(ICmp, CT.Captures[6]->getUser()); 133 EXPECT_EQ(1u, CT.Captures[6]->getOperandNo()); 134 } 135