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[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.

llvm-svn: 182997
This commit is contained in:
Evgeniy Stepanov 2013-05-31 12:04:29 +00:00
parent 96284becf4
commit 888385e40f
2 changed files with 9 additions and 6 deletions
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10
llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
View File

@ -366,11 +366,13 @@ bool MemorySanitizer::doInitialization(Module &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;
}

5
llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll
View File

@ -10,8 +10,9 @@ target triple = "x86_64-unknown-linux-gnu"
; 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 [{{.*}}]