[llvm] r182997 - [msan] Handle mixed track-origins and keep-going settings (llvm part).

[Evgeniy Stepanov]

Author: eugenis
Date: Fri May 31 07:04:29 2013
New Revision: 182997

URL: http://llvm.org/viewvc/llvm-project?rev=182997&view=rev
Log:
[msan] Handle mixed track-origins and keep-going settings (llvm part).

Before this change, each module defined a weak_odr global __msan_track_origins 
with a value of 1 if origin tracking is enabled, 0 if disabled. If there are 
modules with different values, any of them may win. If 0 wins, and there is at 
least one module with 1, the program will most likely crash.

With this change, __msan_track_origins is only emitted if origin tracking is 
on. Then runtime library detects if there is at least one module with origin 
tracking, and enables runtime support for it.


Modified:
    llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp
    llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll

Modified: llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp?rev=182997&r1=182996&r2=182997&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/MemorySanitizer.cpp Fri May 31 07:04:29 2013
@@ -366,11 +366,13 @@ bool MemorySanitizer::doInitialization(M
   appendToGlobalCtors(M, cast<Function>(M.getOrInsertFunction(
                       "__msan_init", IRB.getVoidTy(), NULL)), 0);
 
-  new GlobalVariable(M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
-                     IRB.getInt32(TrackOrigins), "__msan_track_origins");
+  if (TrackOrigins)
+    new GlobalVariable(M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
+                       IRB.getInt32(TrackOrigins), "__msan_track_origins");
 
-  new GlobalVariable(M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
-                     IRB.getInt32(ClKeepGoing), "__msan_keep_going");
+  if (ClKeepGoing)
+    new GlobalVariable(M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
+                       IRB.getInt32(ClKeepGoing), "__msan_keep_going");
 
   return true;
 }

Modified: llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll?rev=182997&r1=182996&r2=182997&view=diff
==============================================================================
--- llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll (original)
+++ llvm/trunk/test/Instrumentation/MemorySanitizer/msan_basic.ll Fri May 31 07:04:29 2013
@@ -10,8 +10,9 @@ target triple = "x86_64-unknown-linux-gn
 
 ; Check the presence and the linkage type of __msan_track_origins and
 ; other interface symbols.
-; CHECK: @__msan_track_origins = weak_odr constant i32 0
-; CHECK: @__msan_keep_going = weak_odr constant i32 0
+; CHECK-NOT: @__msan_track_origins
+; CHECK-ORIGINS: @__msan_track_origins = weak_odr constant i32 1
+; CHECK-NOT: @__msan_keep_going = weak_odr constant i32 0
 ; CHECK: @__msan_retval_tls = external thread_local(initialexec) global [{{.*}}]
 ; CHECK: @__msan_retval_origin_tls = external thread_local(initialexec) global i32
 ; CHECK: @__msan_param_tls = external thread_local(initialexec) global [{{.*}}]