r252063 - [modules] Generalize the workaround for multiple ambiguous definitions of
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Wed Nov 4 11:26:33 PST 2015
Author: rsmith
Date: Wed Nov 4 13:26:32 2015
New Revision: 252063
URL: http://llvm.org/viewvc/llvm-project?rev=252063&view=rev
Log:
[modules] Generalize the workaround for multiple ambiguous definitions of
internal linkage entities in different modules from r250884 to apply to all
names, not just function names.
This is really awkward: we don't want to merge internal-linkage symbols from
separate modules, because they might not actually be defining the same entity.
But we don't want to reject programs that use such an ambiguous symbol if those
internal-linkage symbols are in fact equivalent. For now, we're resolving the
ambiguity by picking one of the equivalent definitions as an extension.
Modified:
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/include/clang/Sema/Sema.h
cfe/trunk/lib/Sema/SemaLookup.cpp
cfe/trunk/lib/Sema/SemaOverload.cpp
cfe/trunk/test/Modules/Inputs/libstdcxx-ambiguous-internal/a.h
cfe/trunk/test/Modules/Inputs/libstdcxx-ambiguous-internal/d.h
cfe/trunk/test/Modules/libstdcxx-ambiguous-internal.cpp
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=252063&r1=252062&r2=252063&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Wed Nov 4 13:26:32 2015
@@ -2986,9 +2986,6 @@ def note_ovl_candidate : Note<"candidate
"%select{none|const|restrict|const and restrict|volatile|const and volatile"
"|volatile and restrict|const, volatile, and restrict}4)"
"| made ineligible by enable_if}2">;
-def ext_ovl_equivalent_internal_linkage_functions_in_modules : ExtWarn<
- "ambiguous use of internal linkage function %0 defined in multiple modules">,
- InGroup<DiagGroup<"modules-ambiguous-internal-linkage-function">>;
def note_ovl_candidate_inherited_constructor : Note<"inherited from here">;
def note_ovl_candidate_illegal_constructor : Note<
@@ -7869,6 +7866,12 @@ def err_module_self_import : Error<
"import of module '%0' appears within same top-level module '%1'">;
def err_module_import_in_implementation : Error<
"@import of module '%0' in implementation of '%1'; use #import">;
+
+def ext_equivalent_internal_linkage_decl_in_modules : ExtWarn<
+ "ambiguous use of internal linkage declaration %0 defined in multiple modules">,
+ InGroup<DiagGroup<"modules-ambiguous-internal-linkage">>;
+def note_equivalent_internal_linkage_decl : Note<
+ "declared here%select{ in module '%1'|}0">;
}
let CategoryName = "Coroutines Issue" in {
Modified: cfe/trunk/include/clang/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=252063&r1=252062&r2=252063&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Sema.h (original)
+++ cfe/trunk/include/clang/Sema/Sema.h Wed Nov 4 13:26:32 2015
@@ -1386,6 +1386,15 @@ public:
hasVisibleDefaultArgument(const NamedDecl *D,
llvm::SmallVectorImpl<Module *> *Modules = nullptr);
+ /// Determine if \p A and \p B are equivalent internal linkage declarations
+ /// from different modules, and thus an ambiguity error can be downgraded to
+ /// an extension warning.
+ bool isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
+ const NamedDecl *B);
+ void diagnoseEquivalentInternalLinkageDeclarations(
+ SourceLocation Loc, const NamedDecl *D,
+ ArrayRef<const NamedDecl *> Equiv);
+
bool RequireCompleteType(SourceLocation Loc, QualType T,
TypeDiagnoser &Diagnoser);
bool RequireCompleteType(SourceLocation Loc, QualType T,
Modified: cfe/trunk/lib/Sema/SemaLookup.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaLookup.cpp?rev=252063&r1=252062&r2=252063&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaLookup.cpp (original)
+++ cfe/trunk/lib/Sema/SemaLookup.cpp Wed Nov 4 13:26:32 2015
@@ -463,8 +463,11 @@ void LookupResult::resolveKind() {
llvm::SmallDenseMap<QualType, unsigned, 16> UniqueTypes;
bool Ambiguous = false;
- bool HasTag = false, HasFunction = false, HasNonFunction = false;
+ bool HasTag = false, HasFunction = false;
bool HasFunctionTemplate = false, HasUnresolved = false;
+ NamedDecl *HasNonFunction = nullptr;
+
+ llvm::SmallVector<NamedDecl*, 4> EquivalentNonFunctions;
unsigned UniqueTagIndex = 0;
@@ -533,9 +536,21 @@ void LookupResult::resolveKind() {
} else if (isa<FunctionDecl>(D)) {
HasFunction = true;
} else {
- if (HasNonFunction)
+ if (HasNonFunction) {
+ // If we're about to create an ambiguity between two declarations that
+ // are equivalent, but one is an internal linkage declaration from one
+ // module and the other is an internal linkage declaration from another
+ // module, just skip it.
+ if (getSema().isEquivalentInternalLinkageDeclaration(HasNonFunction,
+ D)) {
+ EquivalentNonFunctions.push_back(D);
+ Decls[I] = Decls[--N];
+ continue;
+ }
+
Ambiguous = true;
- HasNonFunction = true;
+ }
+ HasNonFunction = D;
}
I++;
}
@@ -558,6 +573,12 @@ void LookupResult::resolveKind() {
Ambiguous = true;
}
+ // FIXME: This diagnostic should really be delayed until we're done with
+ // the lookup result, in case the ambiguity is resolved by the caller.
+ if (!EquivalentNonFunctions.empty() && !Ambiguous)
+ getSema().diagnoseEquivalentInternalLinkageDeclarations(
+ getNameLoc(), HasNonFunction, EquivalentNonFunctions);
+
Decls.set_size(N);
if (HasNonFunction && (HasFunction || HasUnresolved))
Modified: cfe/trunk/lib/Sema/SemaOverload.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaOverload.cpp?rev=252063&r1=252062&r2=252063&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaOverload.cpp (original)
+++ cfe/trunk/lib/Sema/SemaOverload.cpp Wed Nov 4 13:26:32 2015
@@ -8575,22 +8575,38 @@ bool clang::isBetterOverloadCandidate(Se
return false;
}
-/// Determine whether two function declarations are "equivalent" for overload
-/// resolution purposes. This applies when the same internal linkage function
-/// is defined by two modules (textually including the same header). In such
-/// a case, we don't consider the declarations to declare the same entity, but
-/// we also don't want lookups with both declarations visible to be ambiguous
-/// in some cases (this happens when using a modularized libstdc++).
-static bool isEquivalentCompatibleOverload(Sema &S,
- const OverloadCandidate &Best,
- const OverloadCandidate &Cand) {
- return Best.Function && Cand.Function &&
- Best.Function->getDeclContext()->getRedeclContext()->Equals(
- Cand.Function->getDeclContext()->getRedeclContext()) &&
- S.getOwningModule(Best.Function) != S.getOwningModule(Cand.Function) &&
- !Best.Function->isExternallyVisible() &&
- !Cand.Function->isExternallyVisible() &&
- !S.IsOverload(Best.Function, Cand.Function, /*UsingDecl*/false);
+/// Determine whether two declarations are "equivalent" for the purposes of
+/// name lookup and overload resolution. This applies when the same internal
+/// linkage variable or function is defined by two modules (textually including
+/// the same header). In such a case, we don't consider the declarations to
+/// declare the same entity, but we also don't want lookups with both
+/// declarations visible to be ambiguous in some cases (this happens when using
+/// a modularized libstdc++).
+bool Sema::isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
+ const NamedDecl *B) {
+ return A && B && isa<ValueDecl>(A) && isa<ValueDecl>(B) &&
+ A->getDeclContext()->getRedeclContext()->Equals(
+ B->getDeclContext()->getRedeclContext()) &&
+ getOwningModule(const_cast<NamedDecl *>(A)) !=
+ getOwningModule(const_cast<NamedDecl *>(B)) &&
+ !A->isExternallyVisible() && !B->isExternallyVisible() &&
+ Context.hasSameType(cast<ValueDecl>(A)->getType(),
+ cast<ValueDecl>(B)->getType());
+}
+
+void Sema::diagnoseEquivalentInternalLinkageDeclarations(
+ SourceLocation Loc, const NamedDecl *D, ArrayRef<const NamedDecl *> Equiv) {
+ Diag(Loc, diag::ext_equivalent_internal_linkage_decl_in_modules) << D;
+
+ Module *M = getOwningModule(const_cast<NamedDecl*>(D));
+ Diag(D->getLocation(), diag::note_equivalent_internal_linkage_decl)
+ << !M << (M ? M->getFullModuleName() : "");
+
+ for (auto *E : Equiv) {
+ Module *M = getOwningModule(const_cast<NamedDecl*>(E));
+ Diag(E->getLocation(), diag::note_equivalent_internal_linkage_decl)
+ << !M << (M ? M->getFullModuleName() : "");
+ }
}
static void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand,
@@ -8623,7 +8639,7 @@ OverloadCandidateSet::BestViableFunction
if (Best == end())
return OR_No_Viable_Function;
- llvm::SmallVector<const OverloadCandidate *, 4> EquivalentCands;
+ llvm::SmallVector<const NamedDecl *, 4> EquivalentCands;
// Make sure that this function is better than every other viable
// function. If not, we have an ambiguity.
@@ -8632,8 +8648,9 @@ OverloadCandidateSet::BestViableFunction
Cand != Best &&
!isBetterOverloadCandidate(S, *Best, *Cand, Loc,
UserDefinedConversion)) {
- if (isEquivalentCompatibleOverload(S, *Best, *Cand)) {
- EquivalentCands.push_back(Cand);
+ if (S.isEquivalentInternalLinkageDeclaration(Best->Function,
+ Cand->Function)) {
+ EquivalentCands.push_back(Cand->Function);
continue;
}
@@ -8648,13 +8665,9 @@ OverloadCandidateSet::BestViableFunction
S.isFunctionConsideredUnavailable(Best->Function)))
return OR_Deleted;
- if (!EquivalentCands.empty()) {
- S.Diag(Loc, diag::ext_ovl_equivalent_internal_linkage_functions_in_modules)
- << Best->Function;
- S.NoteOverloadCandidate(Best->Function);
- for (auto *Cand : EquivalentCands)
- S.NoteOverloadCandidate(Cand->Function);
- }
+ if (!EquivalentCands.empty())
+ S.diagnoseEquivalentInternalLinkageDeclarations(Loc, Best->Function,
+ EquivalentCands);
return OR_Success;
}
Modified: cfe/trunk/test/Modules/Inputs/libstdcxx-ambiguous-internal/a.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/libstdcxx-ambiguous-internal/a.h?rev=252063&r1=252062&r2=252063&view=diff
==============================================================================
--- cfe/trunk/test/Modules/Inputs/libstdcxx-ambiguous-internal/a.h (original)
+++ cfe/trunk/test/Modules/Inputs/libstdcxx-ambiguous-internal/a.h Wed Nov 4 13:26:32 2015
@@ -1,4 +1,5 @@
#ifndef A_H
#define A_H
static inline void f() {}
+constexpr int n = 0;
#endif
Modified: cfe/trunk/test/Modules/Inputs/libstdcxx-ambiguous-internal/d.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/libstdcxx-ambiguous-internal/d.h?rev=252063&r1=252062&r2=252063&view=diff
==============================================================================
--- cfe/trunk/test/Modules/Inputs/libstdcxx-ambiguous-internal/d.h (original)
+++ cfe/trunk/test/Modules/Inputs/libstdcxx-ambiguous-internal/d.h Wed Nov 4 13:26:32 2015
@@ -1,3 +1,4 @@
#include "b.h"
#include "c.h"
inline void g() { f(); }
+inline int h() { return n; }
Modified: cfe/trunk/test/Modules/libstdcxx-ambiguous-internal.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/libstdcxx-ambiguous-internal.cpp?rev=252063&r1=252062&r2=252063&view=diff
==============================================================================
--- cfe/trunk/test/Modules/libstdcxx-ambiguous-internal.cpp (original)
+++ cfe/trunk/test/Modules/libstdcxx-ambiguous-internal.cpp Wed Nov 4 13:26:32 2015
@@ -3,5 +3,11 @@
// RUN: %clang_cc1 -x c++ -std=c++11 -fmodules -emit-module -fmodule-name=std -fmodules-cache-path=%t %S/Inputs/libstdcxx-ambiguous-internal/module.modulemap -fmodules-local-submodule-visibility -DAMBIGUOUS 2>&1| FileCheck %s
// CHECK-NOT: error
-// CHECK: warning: ambiguous use of internal linkage function 'f' defined in multiple modules
+// CHECK: warning: ambiguous use of internal linkage declaration 'f' defined in multiple modules
+// CHECK: note: declared here in module 'std.C'
+// CHECK: note: declared here in module 'std.B'
+// CHECK-NOT: error
+// CHECK: warning: ambiguous use of internal linkage declaration 'n' defined in multiple modules
+// CHECK: note: declared here in module 'std.C'
+// CHECK: note: declared here in module 'std.B'
// CHECK-NOT: error
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