[ThinLTO] Auto-hide prevailing linkonce_odr only when all copies eligible
Summary:
We hit undefined references building with ThinLTO when one source file
contained explicit instantiations of a template method (weak_odr) but
there were also implicit instantiations in another file (linkonce_odr),
and the latter was the prevailing copy. In this case the symbol was
marked hidden when the prevailing linkonce_odr copy was promoted to
weak_odr. It led to unsats when the resulting shared library was linked
with other code that contained a reference (expecting to be resolved due
to the explicit instantiation).
Add a CanAutoHide flag to the GV summary to allow the thin link to
identify when all copies are eligible for auto-hiding (because they were
all originally linkonce_odr global unnamed addr), and only do the
auto-hide in that case.
Most of the changes here are due to plumbing the new flag through the
bitcode and llvm assembly, and resulting test changes. I augmented the
existing auto-hide test to check for this situation.
Reviewers: pcc
Subscribers: mehdi_amini, inglorion, eraman, dexonsmith, arphaman, dang, llvm-commits, steven_wu, wmi
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59709
llvm-svn: 360466
diff --git a/llvm/lib/AsmParser/LLLexer.cpp b/llvm/lib/AsmParser/LLLexer.cpp
index bc3776d..c0b9cd1 100644
--- a/llvm/lib/AsmParser/LLLexer.cpp
+++ b/llvm/lib/AsmParser/LLLexer.cpp
@@ -733,6 +733,7 @@
KEYWORD(notEligibleToImport);
KEYWORD(live);
KEYWORD(dsoLocal);
+ KEYWORD(canAutoHide);
KEYWORD(function);
KEYWORD(insts);
KEYWORD(funcFlags);
diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 907bbdd..9558bd0 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -7859,7 +7859,7 @@
StringRef ModulePath;
GlobalValueSummary::GVFlags GVFlags = GlobalValueSummary::GVFlags(
/*Linkage=*/GlobalValue::ExternalLinkage, /*NotEligibleToImport=*/false,
- /*Live=*/false, /*IsLocal=*/false);
+ /*Live=*/false, /*IsLocal=*/false, /*CanAutoHide=*/false);
unsigned InstCount;
std::vector<FunctionSummary::EdgeTy> Calls;
FunctionSummary::TypeIdInfo TypeIdInfo;
@@ -7929,7 +7929,7 @@
StringRef ModulePath;
GlobalValueSummary::GVFlags GVFlags = GlobalValueSummary::GVFlags(
/*Linkage=*/GlobalValue::ExternalLinkage, /*NotEligibleToImport=*/false,
- /*Live=*/false, /*IsLocal=*/false);
+ /*Live=*/false, /*IsLocal=*/false, /*CanAutoHide=*/false);
GlobalVarSummary::GVarFlags GVarFlags(/*ReadOnly*/ false);
std::vector<ValueInfo> Refs;
if (ParseToken(lltok::colon, "expected ':' here") ||
@@ -7972,7 +7972,7 @@
StringRef ModulePath;
GlobalValueSummary::GVFlags GVFlags = GlobalValueSummary::GVFlags(
/*Linkage=*/GlobalValue::ExternalLinkage, /*NotEligibleToImport=*/false,
- /*Live=*/false, /*IsLocal=*/false);
+ /*Live=*/false, /*IsLocal=*/false, /*CanAutoHide=*/false);
if (ParseToken(lltok::colon, "expected ':' here") ||
ParseToken(lltok::lparen, "expected '(' here") ||
ParseModuleReference(ModulePath) ||
@@ -8462,41 +8462,55 @@
/// GVFlags
/// ::= 'flags' ':' '(' 'linkage' ':' OptionalLinkageAux ','
/// 'notEligibleToImport' ':' Flag ',' 'live' ':' Flag ','
-/// 'dsoLocal' ':' Flag ')'
+/// 'dsoLocal' ':' Flag ',' 'canAutoHide' ':' Flag ')'
bool LLParser::ParseGVFlags(GlobalValueSummary::GVFlags &GVFlags) {
assert(Lex.getKind() == lltok::kw_flags);
Lex.Lex();
- bool HasLinkage;
if (ParseToken(lltok::colon, "expected ':' here") ||
- ParseToken(lltok::lparen, "expected '(' here") ||
- ParseToken(lltok::kw_linkage, "expected 'linkage' here") ||
- ParseToken(lltok::colon, "expected ':' here"))
+ ParseToken(lltok::lparen, "expected '(' here"))
return true;
- GVFlags.Linkage = parseOptionalLinkageAux(Lex.getKind(), HasLinkage);
- assert(HasLinkage && "Linkage not optional in summary entry");
- Lex.Lex();
-
- unsigned Flag;
- if (ParseToken(lltok::comma, "expected ',' here") ||
- ParseToken(lltok::kw_notEligibleToImport,
- "expected 'notEligibleToImport' here") ||
- ParseToken(lltok::colon, "expected ':' here") || ParseFlag(Flag))
- return true;
- GVFlags.NotEligibleToImport = Flag;
-
- if (ParseToken(lltok::comma, "expected ',' here") ||
- ParseToken(lltok::kw_live, "expected 'live' here") ||
- ParseToken(lltok::colon, "expected ':' here") || ParseFlag(Flag))
- return true;
- GVFlags.Live = Flag;
-
- if (ParseToken(lltok::comma, "expected ',' here") ||
- ParseToken(lltok::kw_dsoLocal, "expected 'dsoLocal' here") ||
- ParseToken(lltok::colon, "expected ':' here") || ParseFlag(Flag))
- return true;
- GVFlags.DSOLocal = Flag;
+ do {
+ unsigned Flag;
+ switch (Lex.getKind()) {
+ case lltok::kw_linkage:
+ Lex.Lex();
+ if (ParseToken(lltok::colon, "expected ':'"))
+ return true;
+ bool HasLinkage;
+ GVFlags.Linkage = parseOptionalLinkageAux(Lex.getKind(), HasLinkage);
+ assert(HasLinkage && "Linkage not optional in summary entry");
+ Lex.Lex();
+ break;
+ case lltok::kw_notEligibleToImport:
+ Lex.Lex();
+ if (ParseToken(lltok::colon, "expected ':'") || ParseFlag(Flag))
+ return true;
+ GVFlags.NotEligibleToImport = Flag;
+ break;
+ case lltok::kw_live:
+ Lex.Lex();
+ if (ParseToken(lltok::colon, "expected ':'") || ParseFlag(Flag))
+ return true;
+ GVFlags.Live = Flag;
+ break;
+ case lltok::kw_dsoLocal:
+ Lex.Lex();
+ if (ParseToken(lltok::colon, "expected ':'") || ParseFlag(Flag))
+ return true;
+ GVFlags.DSOLocal = Flag;
+ break;
+ case lltok::kw_canAutoHide:
+ Lex.Lex();
+ if (ParseToken(lltok::colon, "expected ':'") || ParseFlag(Flag))
+ return true;
+ GVFlags.CanAutoHide = Flag;
+ break;
+ default:
+ return Error(Lex.getLoc(), "expected gv flag type");
+ }
+ } while (EatIfPresent(lltok::comma));
if (ParseToken(lltok::rparen, "expected ')' here"))
return true;
diff --git a/llvm/lib/AsmParser/LLToken.h b/llvm/lib/AsmParser/LLToken.h
index 80a1eb9..33ea28b 100644
--- a/llvm/lib/AsmParser/LLToken.h
+++ b/llvm/lib/AsmParser/LLToken.h
@@ -364,6 +364,7 @@
kw_notEligibleToImport,
kw_live,
kw_dsoLocal,
+ kw_canAutoHide,
kw_function,
kw_insts,
kw_funcFlags,