[llvm] r275247 - [ThinLTO/gold] ThinLTO internalization fixes
Teresa Johnson via llvm-commits
llvm-commits at lists.llvm.org
Tue Jul 12 20:42:41 PDT 2016
Author: tejohnson
Date: Tue Jul 12 22:42:41 2016
New Revision: 275247
URL: http://llvm.org/viewvc/llvm-project?rev=275247&view=rev
Log:
[ThinLTO/gold] ThinLTO internalization fixes
Internalization was missing cases where we originally had a local symbol
that was promoted eagerly but not actually exported. This is because we
were only internalizing the set of global (non-local) symbols that were
PREVAILAING_DEF_IRONLY. Instead, collect the set of global symbols that
are referenced outside of a single IR file, and skip internalization for
those.
Modified:
llvm/trunk/test/tools/gold/X86/thinlto.ll
llvm/trunk/test/tools/gold/X86/thinlto_internalize.ll
llvm/trunk/tools/gold/gold-plugin.cpp
Modified: llvm/trunk/test/tools/gold/X86/thinlto.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/gold/X86/thinlto.ll?rev=275247&r1=275246&r2=275247&view=diff
==============================================================================
--- llvm/trunk/test/tools/gold/X86/thinlto.ll (original)
+++ llvm/trunk/test/tools/gold/X86/thinlto.ll Tue Jul 12 22:42:41 2016
@@ -62,6 +62,8 @@
; BACKEND1-NEXT: </MODULE_STRTAB_BLOCK
; BACKEND1-NEXT: <GLOBALVAL_SUMMARY_BLOCK
; BACKEND1-NEXT: <VERSION
+; One of these will be a COMBINED_ORIGINAL_NAME since f can be internalized.
+; BACKEND1-NEXT: <COMBINED
; BACKEND1-NEXT: <COMBINED
; BACKEND1-NEXT: <COMBINED
; BACKEND1-NEXT: </GLOBALVAL_SUMMARY_BLOCK
Modified: llvm/trunk/test/tools/gold/X86/thinlto_internalize.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/gold/X86/thinlto_internalize.ll?rev=275247&r1=275246&r2=275247&view=diff
==============================================================================
--- llvm/trunk/test/tools/gold/X86/thinlto_internalize.ll (original)
+++ llvm/trunk/test/tools/gold/X86/thinlto_internalize.ll Tue Jul 12 22:42:41 2016
@@ -11,11 +11,18 @@
; f() should be internalized and eliminated after inlining
; CHECK-NOT: @f()
+; h() should be internalized after promotion, and eliminated after inlining
+; CHECK-NOT: @h.llvm.
+
target triple = "x86_64-unknown-linux-gnu"
define i32 @g() {
call void @f()
+ call void @h()
ret i32 0
}
define void @f() {
ret void
}
+define internal void @h() {
+ ret void
+}
Modified: llvm/trunk/tools/gold/gold-plugin.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/gold/gold-plugin.cpp?rev=275247&r1=275246&r2=275247&view=diff
==============================================================================
--- llvm/trunk/tools/gold/gold-plugin.cpp (original)
+++ llvm/trunk/tools/gold/gold-plugin.cpp Tue Jul 12 22:42:41 2016
@@ -1323,10 +1323,9 @@ static ld_plugin_status thinLTOLink(raw_
// interfaces with gold.
DenseMap<void *, std::unique_ptr<PluginInputFile>> HandleToInputFile;
- // Keep track of internalization candidates as well as those that may not
- // be internalized because they are refereneced from other IR modules.
- DenseSet<GlobalValue::GUID> Internalize;
- DenseSet<GlobalValue::GUID> CrossReferenced;
+ // Keep track of symbols that must not be internalized because they
+ // are referenced outside of a single IR module.
+ DenseSet<GlobalValue::GUID> Preserve;
ModuleSummaryIndex CombinedIndex;
uint64_t NextModuleId = 0;
@@ -1352,23 +1351,17 @@ static ld_plugin_status thinLTOLink(raw_
if (Index)
CombinedIndex.mergeFrom(std::move(Index), ++NextModuleId);
- // Look for internalization candidates based on gold's symbol resolution
- // information. Also track symbols referenced from other IR modules.
+ // Use gold's symbol resolution information to identify symbols referenced
+ // by more than a single IR module (before importing, which is checked
+ // separately).
for (auto &Sym : F.syms) {
ld_plugin_symbol_resolution Resolution =
(ld_plugin_symbol_resolution)Sym.resolution;
- if (Resolution == LDPR_PREVAILING_DEF_IRONLY)
- Internalize.insert(GlobalValue::getGUID(Sym.name));
- if (Resolution == LDPR_RESOLVED_IR || Resolution == LDPR_PREEMPTED_IR)
- CrossReferenced.insert(GlobalValue::getGUID(Sym.name));
+ if (Resolution != LDPR_PREVAILING_DEF_IRONLY)
+ Preserve.insert(GlobalValue::getGUID(Sym.name));
}
}
- // Remove symbols referenced from other IR modules from the internalization
- // candidate set.
- for (auto &S : CrossReferenced)
- Internalize.erase(S);
-
// Collect for each module the list of function it defines (GUID ->
// Summary).
StringMap<std::map<GlobalValue::GUID, GlobalValueSummary *>>
@@ -1387,7 +1380,7 @@ static ld_plugin_status thinLTOLink(raw_
const auto &ExportList = ExportLists.find(ModuleIdentifier);
return (ExportList != ExportLists.end() &&
ExportList->second.count(GUID)) ||
- !Internalize.count(GUID);
+ Preserve.count(GUID);
};
// Use global summary-based analysis to identify symbols that can be
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