Prototype of modules codegen
First pass at generating weak definitions of inline functions from module files
(& skipping (-O0) or emitting available_externally (optimizations)
definitions where those modules are used).
External functions defined in modules are emitted into the modular
object file as well (this may turn an existing ODR violation (if that
module were imported into multiple translations) into valid/linkable
code).
Internal symbols (static functions, for example) are not correctly
supported yet. The symbol will be produced, internal, in the modular
object - unreferenceable from the users.
Reviewers: rsmith
Differential Revision: https://reviews.llvm.org/D28845
llvm-svn: 293456
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 07721b2..1539a52 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -8882,8 +8882,22 @@
}
GVALinkage ASTContext::GetGVALinkageForFunction(const FunctionDecl *FD) const {
- return adjustGVALinkageForAttributes(
+ auto L = adjustGVALinkageForAttributes(
*this, basicGVALinkageForFunction(*this, FD), FD);
+ auto EK = ExternalASTSource::EK_ReplyHazy;
+ if (auto *Ext = getExternalSource())
+ EK = Ext->hasExternalDefinitions(FD->getOwningModuleID());
+ switch (EK) {
+ case ExternalASTSource::EK_Never:
+ if (L == GVA_DiscardableODR)
+ return GVA_StrongODR;
+ break;
+ case ExternalASTSource::EK_Always:
+ return GVA_AvailableExternally;
+ case ExternalASTSource::EK_ReplyHazy:
+ break;
+ }
+ return L;
}
static GVALinkage basicGVALinkageForVariable(const ASTContext &Context,
@@ -8968,7 +8982,7 @@
*this, basicGVALinkageForVariable(*this, VD), VD);
}
-bool ASTContext::DeclMustBeEmitted(const Decl *D) {
+bool ASTContext::DeclMustBeEmitted(const Decl *D, bool ForModularCodegen) {
if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
if (!VD->isFileVarDecl())
return false;
@@ -9032,10 +9046,15 @@
}
}
+ GVALinkage Linkage = GetGVALinkageForFunction(FD);
+
+ if (Linkage == GVA_DiscardableODR && ForModularCodegen)
+ return true;
+
// static, static inline, always_inline, and extern inline functions can
// always be deferred. Normal inline functions can be deferred in C99/C++.
// Implicit template instantiations can also be deferred in C++.
- return !isDiscardableGVALinkage(GetGVALinkageForFunction(FD));
+ return !isDiscardableGVALinkage(Linkage);
}
const VarDecl *VD = cast<VarDecl>(D);