[PATCH] D79392: [SanitizerCoverage] Replace the unconditional store with a load, then a conditional store.

[Pratyai Mazumder via Phabricator via llvm-commits]

pratyai created this revision.
Herald added subscribers: llvm-commits, hiraditya.
Herald added a project: LLVM.
pratyai added reviewers: vitalybuka, kcc.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D79392

Files:
  llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
  llvm/test/Instrumentation/SanitizerCoverage/inline-bool-flag.ll


Index: llvm/test/Instrumentation/SanitizerCoverage/inline-bool-flag.ll
===================================================================
--- llvm/test/Instrumentation/SanitizerCoverage/inline-bool-flag.ll
+++ llvm/test/Instrumentation/SanitizerCoverage/inline-bool-flag.ll
@@ -1,13 +1,18 @@
 ; Test -sanitizer-coverage-inline-bool-flag=1
-; RUN: opt < %s -sancov -sanitizer-coverage-level=1 -sanitizer-coverage-inline-bool-flag=1  -S | FileCheck %s
-; RUN: opt < %s -passes='module(sancov-module)' -sanitizer-coverage-level=1 -sanitizer-coverage-inline-bool-flag=1  -S | FileCheck %s
+; RUN: opt < %s -sancov -sanitizer-coverage-level=1 -sanitizer-coverage-inline-bool-flag=1  -S | FileCheck --dump-input=fail %s
+; RUN: opt < %s -passes='module(sancov-module)' -sanitizer-coverage-level=1 -sanitizer-coverage-inline-bool-flag=1  -S | FileCheck --dump-input=fail %s
 
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 target triple = "x86_64-unknown-linux-gnu"
 define void @foo() {
 entry:
 ; CHECK: @__sancov_gen_ = private global [1 x i1] zeroinitializer, section "__sancov_bools", comdat($foo), align 1, !associated !0
+; CHECK: %0 = load i1, i1* getelementptr inbounds ([1 x i1], [1 x i1]* @__sancov_gen_, i64 0, i64 0), align 1, !nosanitize !1
+; CHECK: br i1 %0, label %1, label %2
+; CHECK: 1: ; preds = %entry
 ; CHECK: store i1 true, i1* getelementptr inbounds ([1 x i1], [1 x i1]* @__sancov_gen_, i64 0, i64 0), align 1, !nosanitize !1
+; CHECK: br label %2
+; CHECK: 2: ; preds = %entry, %1
   ret void
 }
 ; CHECK: call void @__sanitizer_cov_bool_flag_init(i1* bitcast (i1** @__start___sancov_bools to i1*), i1* bitcast (i1** @__stop___sancov_bools to i1*))
Index: llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -945,7 +945,11 @@
     auto FlagPtr = IRB.CreateGEP(
         FunctionBoolArray->getValueType(), FunctionBoolArray,
         {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)});
-    auto Store = IRB.CreateStore(ConstantInt::getTrue(Int1Ty), FlagPtr);
+    auto Load = IRB.CreateLoad(Int1Ty, FlagPtr);
+    auto ThenTerm = SplitBlockAndInsertIfThen(Load, &*IP, false);
+    IRBuilder<> ThenIRB(ThenTerm);
+    auto Store = ThenIRB.CreateStore(ConstantInt::getTrue(Int1Ty), FlagPtr);
+    SetNoSanitizeMetadata(Load);
     SetNoSanitizeMetadata(Store);
   }
   if (Options.StackDepth && IsEntryBB && !IsLeafFunc) {


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