unittests/Analysis/CaptureTrackingTest.cpp

   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/Analysis/OrderedBasicBlock.h"
  11 #include "llvm/AsmParser/Parser.h"
  12 #include "llvm/IR/Dominators.h"
  13 #include "llvm/IR/Instructions.h"
  14 #include "llvm/IR/LLVMContext.h"
  15 #include "llvm/IR/Module.h"
  16 #include "llvm/Support/SourceMgr.h"
  17 #include "gtest/gtest.h"
  18
  19 using namespace llvm;
  20
  21 TEST(CaptureTracking, MaxUsesToExplore) {
  22   StringRef Assembly = R"(
  23     ; Function Attrs: nounwind ssp uwtable
  24     declare void @doesnt_capture(i8* nocapture, i8* nocapture, i8* nocapture,
  25                                  i8* nocapture, i8* nocapture)
  26
  27     ; %arg has 5 uses
  28     define void @test_few_uses(i8* %arg) {
  29       call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg)
  30       ret void
  31     }
  32
  33     ; %arg has 50 uses
  34     define void @test_many_uses(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       call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg)
  45       ret void
  46     }
  47   )";
  48
  49   LLVMContext Context;
  50   SMDiagnostic Error;
  51   auto M = parseAssemblyString(Assembly, Error, Context);
  52   ASSERT_TRUE(M) << "Bad assembly?";
  53
  54   auto Test = [&M](const char *FName, unsigned FalseMaxUsesLimit,
  55                    unsigned TrueMaxUsesLimit) {
  56     Function *F = M->getFunction(FName);
  57     ASSERT_NE(F, nullptr);
  58     Value *Arg = &*F->arg_begin();
  59     ASSERT_NE(Arg, nullptr);
  60     ASSERT_FALSE(PointerMayBeCaptured(Arg, true, true, FalseMaxUsesLimit));
  61     ASSERT_TRUE(PointerMayBeCaptured(Arg, true, true, TrueMaxUsesLimit));
  62
  63     BasicBlock *EntryBB = &F->getEntryBlock();
  64     DominatorTree DT(*F);
  65     OrderedBasicBlock OBB(EntryBB);
  66
  67     Instruction *Ret = EntryBB->getTerminator();
  68     ASSERT_TRUE(isa<ReturnInst>(Ret));
  69     ASSERT_FALSE(PointerMayBeCapturedBefore(Arg, true, true, Ret, &DT, false,
  70                                             &OBB, FalseMaxUsesLimit));
  71     ASSERT_TRUE(PointerMayBeCapturedBefore(Arg, true, true, Ret, &DT, false,
  72                                            &OBB, TrueMaxUsesLimit));
  73   };
  74
  75   Test("test_few_uses", 6, 4);
  76   Test("test_many_uses", 50, 30);
  77 }