RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-22 18:54:02 +01:00
Code Issues Projects Releases Wiki Activity

[ThinLTO] Keep common symbols in ThinLTO modules

Browse Source 
Summary:
Skip the merging of common symbols for ThinLTO modules, they will be
merged by the final native object link. Trying to merge the symbols and
add to a combined module will incorrectly enable the common symbol to be
internalized in the ThinLTO module. Additionally, we will not want to
create a combined module for ThinLTO distributed builds.

This fixes failures in 7 cpu2006 benchmarks from the new LTO API in
ThinLTO mode.

Reviewers: mehdi_amini

Subscribers: pcc, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D23637

llvm-svn: 279023
This commit is contained in:
Teresa Johnson 2016-08-18 01:08:50 +00:00
parent d84c46a824
commit 67dcfd5101
4 changed files with 59 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/llvm/LTO/LTO.h
View File

@ -228,6 +228,10 @@ public:
StringRef getSourceFileName() const {
return Obj->getModule().getSourceFileName();
}
MemoryBufferRef getMemoryBufferRef() const {
return Obj->getMemoryBufferRef();
}
};
/// A ThinBackend defines what happens after the thin-link phase during ThinLTO.

13
test/tools/gold/X86/Inputs/common_thinlto.ll Normal file
View File

@ -0,0 +1,13 @@
source_filename = "common2.c"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@P = external global i8* (...)*, align 8
; Function Attrs: nounwind uwtable
define void @foo() #0 {
entry:
%0 = load i8* (...)*, i8* (...)** @P, align 8
%call = call i8* (...) %0()
ret void
}

38
test/tools/gold/X86/common_thinlto.ll Normal file
View File

@ -0,0 +1,38 @@
; RUN: opt -module-summary %s -o %t1.o
; RUN: opt -module-summary %p/Inputs/common_thinlto.ll -o %t2.o
; RUN: %gold -plugin %llvmshlibdir/LLVMgold.so \
; RUN: --plugin-opt=save-temps \
; RUN: --plugin-opt=thinlto \
; RUN: -shared %t1.o %t2.o -o %t3
; RUN: llvm-dis %t1.o.2.internalize.bc -o - | FileCheck %s --check-prefix=INTERNALIZE
; We should not have internalized P, and it should still be common.
; INTERNALIZE: @P = common global
; RUN: llvm-dis %t1.o.4.opt.bc -o - | FileCheck %s --check-prefix=OPT
; bar should still exist (if we had internalized P it would look dead).
; OPT: @bar
; RUN: llvm-nm %t3.o | FileCheck %s --check-prefix=NM
; NM: bar
source_filename = "common1.c"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@P = common global i8* (...)* null, align 8
define i32 @main() {
entry:
store i8* (...)* bitcast (i8* ()* @bar to i8* (...)*), i8* (...)** @P, align 8
%call = call i32 (...) @foo()
ret i32 0
}
declare i32 @foo(...)
define internal i8* @bar() {
entry:
ret i8* null
}

5
tools/gold/gold-plugin.cpp
View File

@ -572,6 +572,8 @@ static void addModule(LTO &Lto, claimed_file &F, const void *View) {
toString(ObjOrErr.takeError()).c_str());
InputFile &Obj = **ObjOrErr;
bool HasThinLTOSummary =
hasGlobalValueSummary(Obj.getMemoryBufferRef(), diagnosticHandler);
unsigned SymNum = 0;
std::vector<SymbolResolution> Resols(F.syms.size());
@ -617,7 +619,8 @@ static void addModule(LTO &Lto, claimed_file &F, const void *View) {
(IsExecutable || !Res.DefaultVisibility))
R.FinalDefinitionInLinkageUnit = true;
if (ObjSym.getFlags() & object::BasicSymbolRef::SF_Common) {
if ((ObjSym.getFlags() & object::BasicSymbolRef::SF_Common) &&
!HasThinLTOSummary) {
// We ignore gold's resolution for common symbols. A common symbol with
// the correct size and alignment is added to the module by the pre-opt
// module hook if any common symbol prevailed.