[llvm] r348221 - [asan] Reduce binary size by using unnamed private aliases

[Vitaly Buka via llvm-commits]

Author: vitalybuka
Date: Mon Dec  3 16:36:14 2018
New Revision: 348221

URL: http://llvm.org/viewvc/llvm-project?rev=348221&view=rev
Log:
[asan] Reduce binary size by using unnamed private aliases

Summary:
--asan-use-private-alias increases binary sizes by 10% or more.
Most of this space was long names of aliases and new symbols.
These symbols are not needed for the ODC check at all.

Reviewers: eugenis

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D55146

Modified:
    llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
    llvm/trunk/test/Instrumentation/AddressSanitizer/local_alias.ll

Modified: llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp?rev=348221&r1=348220&r2=348221&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp Mon Dec  3 16:36:14 2018
@@ -746,7 +746,7 @@ public:
               ClRecover : Recover;
           this->CompileKernel = ClEnableKasan.getNumOccurrences() > 0 ?
               ClEnableKasan : CompileKernel;
-	}
+  }
 
   bool runOnModule(Module &M) override;
   StringRef getPassName() const override { return "AddressSanitizerModule"; }
@@ -2176,8 +2176,8 @@ bool AddressSanitizerModule::InstrumentG
     if (CanUsePrivateAliases && ClUsePrivateAliasForGlobals) {
       // Create local alias for NewGlobal to avoid crash on ODR between
       // instrumented and non-instrumented libraries.
-      auto *GA = GlobalAlias::create(GlobalValue::InternalLinkage,
-                                     NameForGlobal + M.getName(), NewGlobal);
+      auto *GA =
+          GlobalAlias::create(GlobalValue::PrivateLinkage, "", NewGlobal);
 
       // With local aliases, we need to provide another externally visible
       // symbol __odr_asan_XXX to detect ODR violation.

Modified: llvm/trunk/test/Instrumentation/AddressSanitizer/local_alias.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/AddressSanitizer/local_alias.ll?rev=348221&r1=348220&r2=348221&view=diff
==============================================================================
--- llvm/trunk/test/Instrumentation/AddressSanitizer/local_alias.ll (original)
+++ llvm/trunk/test/Instrumentation/AddressSanitizer/local_alias.ll Mon Dec  3 16:36:14 2018
@@ -7,7 +7,7 @@ target triple = "x86_64-unknown-linux-gn
 
 ; Check that we generate internal alias and odr indicator symbols for global to be protected.
 ; CHECK: @__odr_asan_gen_a = internal global i8 0, align 1
-; CHECK: @"a<stdin>" = internal alias { [2 x i32], [56 x i8] }, { [2 x i32], [56 x i8] }* @a
+; CHECK: @0 = private alias { [2 x i32], [56 x i8] }, { [2 x i32], [56 x i8] }* @a
 
 ; Function Attrs: nounwind sanitize_address uwtable
 define i32 @foo(i32 %M) #0 {