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[asan] Upgrade private linkage globals to internal linkage on COFF 

COFF comdats require symbol table entries, which means the comdat leader
cannot have private linkage.

llvm-svn: 317009
This commit is contained in:
Reid Kleckner 2017-10-31 16:16:08 +00:00
parent 68821a8b91
commit c212cc88e2
2 changed files with 16 additions and 2 deletions
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9
llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
View File

@ -1764,9 +1764,14 @@ void AddressSanitizerModule::SetComdatForGlobalMetadata(
C = M.getOrInsertComdat(G->getName());
}
// Make this IMAGE_COMDAT_SELECT_NODUPLICATES on COFF.
if (TargetTriple.isOSBinFormatCOFF())
// Make this IMAGE_COMDAT_SELECT_NODUPLICATES on COFF. Also upgrade private
// linkage to internal linkage so that a symbol table entry is emitted. This
// is necessary in order to create the comdat group.
if (TargetTriple.isOSBinFormatCOFF()) {
C->setSelectionKind(Comdat::NoDuplicates);
if (G->hasPrivateLinkage())
G->setLinkage(GlobalValue::InternalLinkage);
}
G->setComdat(C);
}

9
llvm/test/Instrumentation/AddressSanitizer/global_metadata_windows.ll
View File

@ -12,16 +12,25 @@ target triple = "x86_64-pc-windows-msvc19.0.24215"
$mystr = comdat any
; CHECK: $dead_global = comdat noduplicates
; CHECK: $private_str = comdat noduplicates
; CHECK: @dead_global = local_unnamed_addr global { i32, [60 x i8] } { i32 42, [60 x i8] zeroinitializer }, comdat, align 32
; CHECK: @private_str = internal unnamed_addr constant { [8 x i8], [56 x i8] } { [8 x i8] c"private\00", [56 x i8] zeroinitializer }, comdat, align 32
; CHECK: @__asan_global_dead_global = private global { {{.*}} }, section ".ASAN$GL", comdat($dead_global), align 64
; CHECK: @__asan_global_private_str = private global { {{.*}} }, section ".ASAN$GL", comdat($private_str), align 64
@dead_global = local_unnamed_addr global i32 42, align 4
@mystr = linkonce_odr unnamed_addr constant [5 x i8] c"main\00", comdat, align 1
; Private globals will get upgraded to internal linkage.
@private_str = private unnamed_addr constant [8 x i8] c"private\00", align 1
; Function Attrs: nounwind uwtable
define i32 @main() local_unnamed_addr #0 {
entry:
%call = tail call i32 @puts(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @mystr, i64 0, i64 0))
%call2 = tail call i32 @puts(i8* getelementptr inbounds ([8 x i8], [8 x i8]* @private_str, i64 0, i64 0))
ret i32 0
}