RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2025-02-18 03:07:52 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

ThinLTOCodeGenerator: preserve linkonce when in "MustPreserved" set

Browse Source 
If the linker specifically requested for a linkonce to be preserved,
we need to make sure we won't drop it even if all the uses in the
current module disappear.

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 267543
This commit is contained in:
Mehdi Amini 2016-04-26 10:35:01 +00:00
parent f67be413be
commit 1ebf01e084
2 changed files with 18 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
lib/LTO/ThinLTOCodeGenerator.cpp
View File

@ -137,6 +137,7 @@ bool IsFirstDefinitionForLinker(const GlobalValueSummaryList &GVSummaryList,
static GlobalValue::LinkageTypes
ResolveODR(const ModuleSummaryIndex &Index,
const FunctionImporter::ExportSetTy &ExportList,
const DenseSet<GlobalValue::GUID> &GUIDPreservedSymbols,
StringRef ModuleIdentifier, GlobalValue::GUID GUID,
const GlobalValueSummary &GV) {
auto HasMultipleCopies = [&](const GlobalValueSummaryList &GVSummaryList) {
@ -163,7 +164,7 @@ ResolveODR(const ModuleSummaryIndex &Index,
if (!HasMultipleCopies(GVSummaryList)) {
// Exported LinkonceODR needs to be promoted to not be discarded
if (GlobalValue::isDiscardableIfUnused(OriginalLinkage) &&
ExportList.count(GUID))
(ExportList.count(GUID) || GUIDPreservedSymbols.count(GUID)))
return GlobalValue::WeakODRLinkage;
break;
}
@ -187,6 +188,7 @@ ResolveODR(const ModuleSummaryIndex &Index,
static void ResolveODR(
const ModuleSummaryIndex &Index,
const FunctionImporter::ExportSetTy &ExportList,
const DenseSet<GlobalValue::GUID> &GUIDPreservedSymbols,
const GVSummaryMapTy &DefinedGlobals, StringRef ModuleIdentifier,
std::map<GlobalValue::GUID, GlobalValue::LinkageTypes> &ResolvedODR) {
if (Index.modulePaths().size() == 1)
@ -206,7 +208,7 @@ static void ResolveODR(
if (GlobalInvolvedWithAlias.count(GV.second))
continue;
auto NewLinkage =
ResolveODR(Index, ExportList, ModuleIdentifier, GV.first, *GV.second);
ResolveODR(Index, ExportList, GUIDPreservedSymbols, ModuleIdentifier, GV.first, *GV.second);
if (NewLinkage != GV.second->linkage()) {
ResolvedODR[GV.first] = NewLinkage;
}
@ -681,13 +683,17 @@ void ThinLTOCodeGenerator::promote(Module &TheModule,
ExportLists);
auto &ExportList = ExportLists[ModuleIdentifier];
// Convert the preserved symbols set from string to GUID
auto GUIDPreservedSymbols =
computeGUIDPreservedSymbols(PreservedSymbols, TMBuilder.TheTriple);
// Resolve the LinkOnceODR, trying to turn them into "available_externally"
// where possible.
// This is a compile-time optimization.
// We use a std::map here to be able to have a defined ordering when
// producing a hash for the cache entry.
std::map<GlobalValue::GUID, GlobalValue::LinkageTypes> ResolvedODR;
ResolveODR(Index, ExportList, ModuleToDefinedGVSummaries[ModuleIdentifier],
ResolveODR(Index, ExportList, GUIDPreservedSymbols, ModuleToDefinedGVSummaries[ModuleIdentifier],
ModuleIdentifier, ResolvedODR);
fixupODR(TheModule, ResolvedODR);
@ -841,7 +847,7 @@ void ThinLTOCodeGenerator::run() {
// We use a std::map here to be able to have a defined ordering when
// producing a hash for the cache entry.
std::map<GlobalValue::GUID, GlobalValue::LinkageTypes> ResolvedODR;
ResolveODR(*Index, ExportList, DefinedFunctions, ModuleIdentifier,
ResolveODR(*Index, ExportList, GUIDPreservedSymbols, DefinedFunctions, ModuleIdentifier,
ResolvedODR);
// The module may be cached, this helps handling it.

8
test/ThinLTO/X86/odr_resolution.ll
View File

@ -6,6 +6,8 @@
; Verify that only one ODR is selected across modules, but non ODR are not affected.
; RUN: llvm-lto -thinlto-action=promote %t.bc -thinlto-index=%t3.bc -o - | llvm-dis -o - | FileCheck %s --check-prefix=MOD1
; RUN: llvm-lto -thinlto-action=promote %t2.bc -thinlto-index=%t3.bc -o - | llvm-dis -o - | FileCheck %s --check-prefix=MOD2
; When exported, we always preserve a linkonce
; RUN: llvm-lto -thinlto-action=promote %t.bc -thinlto-index=%t3.bc -o - --exported-symbol=linkonceodrfuncInSingleModule | llvm-dis -o - | FileCheck %s --check-prefix=EXPORTED
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.11.0"
@ -48,3 +50,9 @@ entry:
ret void
}
; MOD1: define linkonce_odr void @linkonceodrfuncInSingleModule()
; EXPORTED: define weak_odr void @linkonceodrfuncInSingleModule()
define linkonce_odr void @linkonceodrfuncInSingleModule() #0 {
entry:
ret void
}