From: Justin Bogner <mail@justinbogner.com>
Date: Fri, 25 Aug 2017 01:24:54 +0000 (+0000)
Subject: [sanitizer-coverage] Make sure pc-tables aren't dead stripped
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=965445287b45049e7cb10cd1208ae077b79d3d65;p=llvm

[sanitizer-coverage] Make sure pc-tables aren't dead stripped

Add a reference to the PC array in llvm.used so that linkers that
aggressively dead strip (like ld64) don't remove it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311742 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Instrumentation/SanitizerCoverage.cpp b/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
index c6f0d17f8fe..fdf265143fd 100644
--- a/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ b/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -557,6 +557,10 @@ void SanitizerCoverageModule::CreatePCArray(Function &F,
   FunctionPCsArray->setInitializer(
       ConstantArray::get(ArrayType::get(Int8PtrTy, N), PCs));
   FunctionPCsArray->setConstant(true);
+
+  // We don't reference the PCs array in any of our runtime functions, so we
+  // need to prevent it from being dead stripped.
+  appendToUsed(*F.getParent(), {FunctionPCsArray});
 }
 
 void SanitizerCoverageModule::CreateFunctionLocalArrays(