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LTO: Do summary-based prevailing symbol resolution at --lto-O0. 

Prevailing symbol resolution is necessary for correctness. Without
this we can end up dropping a referenced linkonce symbol from the link.

Differential Revision: https://reviews.llvm.org/D33570

llvm-svn: 303939
This commit is contained in:
Peter Collingbourne 2017-05-25 23:40:11 +00:00
parent e2133d5b42
commit f87197ad91
2 changed files with 23 additions and 13 deletions
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25
llvm/lib/LTO/LTO.cpp
View File

@ -1002,10 +1002,6 @@ Error LTO::runThinLTO(AddStreamFn AddStream, NativeObjectCache Cache,
ExportedGUIDs.insert(GUID);
}
auto isPrevailing = [&](GlobalValue::GUID GUID,
const GlobalValueSummary *S) {
return ThinLTO.PrevailingModuleForGUID[GUID] == S->modulePath();
};
auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) {
const auto &ExportList = ExportLists.find(ModuleIdentifier);
return (ExportList != ExportLists.end() &&
@ -1013,17 +1009,20 @@ Error LTO::runThinLTO(AddStreamFn AddStream, NativeObjectCache Cache,
ExportedGUIDs.count(GUID);
};
thinLTOInternalizeAndPromoteInIndex(ThinLTO.CombinedIndex, isExported);
auto recordNewLinkage = [&](StringRef ModuleIdentifier,
GlobalValue::GUID GUID,
GlobalValue::LinkageTypes NewLinkage) {
ResolvedODR[ModuleIdentifier][GUID] = NewLinkage;
};
thinLTOResolveWeakForLinkerInIndex(ThinLTO.CombinedIndex, isPrevailing,
recordNewLinkage);
}
auto isPrevailing = [&](GlobalValue::GUID GUID,
const GlobalValueSummary *S) {
return ThinLTO.PrevailingModuleForGUID[GUID] == S->modulePath();
};
auto recordNewLinkage = [&](StringRef ModuleIdentifier,
GlobalValue::GUID GUID,
GlobalValue::LinkageTypes NewLinkage) {
ResolvedODR[ModuleIdentifier][GUID] = NewLinkage;
};
thinLTOResolveWeakForLinkerInIndex(ThinLTO.CombinedIndex, isPrevailing,
recordNewLinkage);
std::unique_ptr<ThinBackendProc> BackendProc =
ThinLTO.Backend(Conf, ThinLTO.CombinedIndex, ModuleToDefinedGVSummaries,
AddStream, Cache);

11
llvm/test/LTO/Resolution/X86/linkonce.ll Normal file
View File

@ -0,0 +1,11 @@
; RUN: opt -module-summary -o %t %s
; RUN: llvm-lto2 run %t -O0 -r %t,foo,px -o %t2
; RUN: llvm-nm %t2.0 | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; CHECK: W foo
define linkonce_odr void @foo() {
ret void
}