[CaptureTracking] Add a unit test for MaxUsesToExplore

llvm-svn: 350351

2 files changed, 79 insertions, 0 deletions

diff --git a/llvm/unittests/Analysis/CMakeLists.txt b/llvm/unittests/Analysis/CMakeLists.txt
index 7d4fd33716e..563b48d4874 100644
--- a/llvm/unittests/Analysis/CMakeLists.txt
+++ b/llvm/unittests/Analysis/CMakeLists.txt
@@ -12,6 +12,7 @@ add_llvm_unittest(AnalysisTests
   BlockFrequencyInfoTest.cpp
   BranchProbabilityInfoTest.cpp
   CallGraphTest.cpp
+  CaptureTrackingTest.cpp
   CFGTest.cpp
   CGSCCPassManagerTest.cpp
   DivergenceAnalysisTest.cpp
diff --git a/llvm/unittests/Analysis/CaptureTrackingTest.cpp b/llvm/unittests/Analysis/CaptureTrackingTest.cpp
new file mode 100644
index 00000000000..ee6e0106a1d
--- /dev/null
+++ b/llvm/unittests/Analysis/CaptureTrackingTest.cpp
@@ -0,0 +1,78 @@
+//=======- CaptureTrackingTest.cpp - Unit test for the Capture Tracking ---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/CaptureTracking.h"
+#include "llvm/Analysis/OrderedBasicBlock.h"
+#include "llvm/AsmParser/Parser.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 "gtest/gtest.h"
+
+using namespace llvm;
+
+TEST(CaptureTracking, MaxUsesToExplore) {
+  StringRef Assembly = R"(
+    ; Function Attrs: nounwind ssp uwtable
+    declare void @doesnt_capture(i8* nocapture, i8* nocapture, i8* nocapture, 
+                                 i8* nocapture, i8* nocapture)
+
+    ; %arg has 5 uses
+    define void @test_few_uses(i8* %arg) {
+      call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg)
+      ret void
+    }
+
+    ; %arg has 50 uses
+    define void @test_many_uses(i8* %arg) {
+      call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg)
+      call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg)
+      call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg)
+      call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg)
+      call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg)
+      call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg)
+      call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg)
+      call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg)
+      call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg)
+      call void @doesnt_capture(i8* %arg, i8* %arg, i8* %arg, i8* %arg, i8* %arg)
+      ret void
+    }
+  )";
+
+  LLVMContext Context;
+  SMDiagnostic Error;
+  auto M = parseAssemblyString(Assembly, Error, Context);
+  ASSERT_TRUE(M) << "Bad assembly?";
+
+  auto Test = [&M](const char *FName, unsigned FalseMaxUsesLimit,
+                   unsigned TrueMaxUsesLimit) {
+    Function *F = M->getFunction(FName);
+    ASSERT_NE(F, nullptr);
+    Value *Arg = &*F->arg_begin();
+    ASSERT_NE(Arg, nullptr);
+    ASSERT_FALSE(PointerMayBeCaptured(Arg, true, true, FalseMaxUsesLimit));
+    ASSERT_TRUE(PointerMayBeCaptured(Arg, true, true, TrueMaxUsesLimit));
+
+    BasicBlock *EntryBB = &F->getEntryBlock();
+    DominatorTree DT(*F);
+    OrderedBasicBlock OBB(EntryBB);
+
+    Instruction *Ret = EntryBB->getTerminator();
+    ASSERT_TRUE(isa<ReturnInst>(Ret));
+    ASSERT_FALSE(PointerMayBeCapturedBefore(Arg, true, true, Ret, &DT, false, 
+                                            &OBB, FalseMaxUsesLimit));
+    ASSERT_TRUE(PointerMayBeCapturedBefore(Arg, true, true, Ret, &DT, false,
+                                           &OBB, TrueMaxUsesLimit));
+  };
+
+  Test("test_few_uses", 6, 4);
+  Test("test_many_uses", 50, 30);
+}