From: Kostya Serebryany <kcc@google.com>
Date: Tue, 20 Sep 2016 00:16:54 +0000 (+0000)
Subject: [sanitizer-coverage] add comdat to coverage guards if needed
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=18f63e47d8fbf58ef85b52ddbf96828825431461;p=llvm

[sanitizer-coverage] add comdat to coverage guards if needed

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281952 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Instrumentation/SanitizerCoverage.cpp b/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
index a2755adc7fa..9e1ff1cd6d2 100644
--- a/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ b/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -669,6 +669,8 @@ void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F, BasicBlock &BB,
     auto GuardVar = new GlobalVariable(
         *F.getParent(), Int64Ty, false, GlobalVariable::LinkOnceODRLinkage,
         Constant::getNullValue(Int64Ty), "__sancov_guard." + F.getName());
+    if (auto Comdat = F.getComdat())
+      GuardVar->setComdat(Comdat);
     // TODO: add debug into to GuardVar.
     GuardVar->setSection(SanCovTracePCGuardSection);
     auto GuardPtr = IRB.CreatePointerCast(GuardVar, IntptrPtrTy);
diff --git a/test/Instrumentation/SanitizerCoverage/tracing-comdat.ll b/test/Instrumentation/SanitizerCoverage/tracing-comdat.ll
new file mode 100644
index 00000000000..f718af53644
--- /dev/null
+++ b/test/Instrumentation/SanitizerCoverage/tracing-comdat.ll
@@ -0,0 +1,13 @@
+; Test that the coverage guards have proper comdat
+; RUN: opt < %s -sancov -sanitizer-coverage-level=3 -sanitizer-coverage-trace-pc-guard  -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+$Foo = comdat any
+; Function Attrs: uwtable
+define linkonce_odr void @Foo() comdat {
+entry:
+  ret void
+}
+
+; CHECK: @__sancov_guard.Foo = linkonce_odr global i64 0, section "__sancov_guards", comdat($Foo)
+