Reinstate r284008 reverted in r284081, with two fixes:
1) Merge and demote variable definitions when we find a redefinition in
MergeVarDecls, not only when we find one in AddInitializerToDecl (we only reach
the second case if it's the addition of the initializer itself that converts an
existing declaration into a definition).
2) When rebuilding a redeclaration chain for a variable, if we merge two
definitions together, mark the definitions as merged so the retained definition
is made visible whenever the demoted definition would have been.
Original commit message (from r283882):
[modules] PR28752: Do not instantiate variable declarations which are not visible.
Original patch by Vassil Vassilev! Changes listed above are mine.
llvm-svn: 284284
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index a0fc155..2146861 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -894,6 +894,7 @@
Record.push_back(D->getTSCSpec());
Record.push_back(D->getInitStyle());
if (!isa<ParmVarDecl>(D)) {
+ Record.push_back(D->isThisDeclarationADemotedDefinition());
Record.push_back(D->isExceptionVariable());
Record.push_back(D->isNRVOVariable());
Record.push_back(D->isCXXForRangeDecl());
@@ -998,6 +999,8 @@
// Check things we know are true of *every* PARM_VAR_DECL, which is more than
// just us assuming it.
assert(!D->getTSCSpec() && "PARM_VAR_DECL can't use TLS");
+ assert(!D->isThisDeclarationADemotedDefinition()
+ && "PARM_VAR_DECL can't be demoted definition.");
assert(D->getAccess() == AS_none && "PARM_VAR_DECL can't be public/private");
assert(!D->isExceptionVariable() && "PARM_VAR_DECL can't be exception var");
assert(D->getPreviousDecl() == nullptr && "PARM_VAR_DECL can't be redecl");
@@ -1957,6 +1960,7 @@
Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // SClass
Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // TSCSpec
Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 2)); // InitStyle
+ Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // IsThisDeclarationADemotedDefinition
Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isExceptionVariable
Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isNRVOVariable
Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isCXXForRangeDecl