https://github.com/cjc0013 updated https://github.com/llvm/llvm-project/pull/219238
>From 26800608844f90546741ee69c9b1461ac87aed59 Mon Sep 17 00:00:00 2001 From: cjc0013 <[email protected]> Date: Thu, 27 Aug 2026 12:26:09 -0400 Subject: [PATCH 1/2] [clang] Disambiguate GMF internal functions across partitions --- clang/lib/AST/ItaniumMangle.cpp | 27 ++++++++++- ...lobal-module-fragment-internal-linkage.cpp | 46 +++++++++++++++++++ 2 files changed, 72 insertions(+), 1 deletion(-) create mode 100644 clang/test/Modules/global-module-fragment-internal-linkage.cpp diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp index 7fb162a68fe88..b172f1a302f0a 100644 --- a/clang/lib/AST/ItaniumMangle.cpp +++ b/clang/lib/AST/ItaniumMangle.cpp @@ -1110,9 +1110,34 @@ void CXXNameMangler::mangleNameWithAbiTags( } void CXXNameMangler::mangleModuleName(const NamedDecl *ND) { - if (ND->isExternallyVisible()) + if (ND->isExternallyVisible()) { if (Module *M = ND->getOwningModuleForLinkage()) mangleModuleNamePrefix(M->getPrimaryModuleInterfaceName()); + return; + } + + // A function with internal linkage in a global module fragment denotes a + // different entity in every module unit. When definitions from multiple + // imported units are emitted into one translation unit, their ordinary + // internal-linkage names would otherwise collide. + const auto *FD = dyn_cast<FunctionDecl>(ND); + Module *M = ND->getOwningModule(); + if (!FD || FD->getFormalLinkage() != Linkage::Internal || !M || + !M->isGlobalModule() || !M->Parent || + !M->Parent->isNamedModuleUnit()) + return; + + M = M->Parent; + if (!M->isModulePartition()) { + mangleModuleNamePrefix(M->Name); + return; + } + + auto [PrimaryName, PartitionName] = StringRef(M->Name).rsplit(':'); + assert(!PrimaryName.empty() && !PartitionName.empty() && + "invalid module partition name"); + mangleModuleNamePrefix(PrimaryName); + mangleModuleNamePrefix(PartitionName, /*IsPartition=*/true); } // <module-name> ::= <module-subname> diff --git a/clang/test/Modules/global-module-fragment-internal-linkage.cpp b/clang/test/Modules/global-module-fragment-internal-linkage.cpp new file mode 100644 index 0000000000000..5298015d92abe --- /dev/null +++ b/clang/test/Modules/global-module-fragment-internal-linkage.cpp @@ -0,0 +1,46 @@ +// RUN: rm -rf %t +// RUN: mkdir -p %t +// RUN: split-file %s %t +// +// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 \ +// RUN: -emit-module-interface %t/part1.cppm -o %t/A-Part1.pcm +// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 \ +// RUN: -emit-module-interface %t/part2.cppm -o %t/A-Part2.pcm +// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 \ +// RUN: -emit-module-interface %t/A.cppm \ +// RUN: -fmodule-file=%t/A-Part1.pcm -fmodule-file=%t/A-Part2.pcm \ +// RUN: -o %t/A.pcm +// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 -emit-llvm -o - \ +// RUN: %t/use.cpp -fmodule-file=%t/A.pcm \ +// RUN: -fmodule-file=%t/A-Part1.pcm -fmodule-file=%t/A-Part2.pcm \ +// RUN: | FileCheck %s +// +// Two internal functions with the same ordinary mangled name must remain +// distinct when their global module fragments are imported together. +// CHECK-DAG: define internal {{.*}} @_ZLW1AWP5Part16helperv() +// CHECK-DAG: define internal {{.*}} @_ZLW1AWP5Part26helperv() +// CHECK-DAG: call {{.*}} @_ZLW1AWP5Part16helperv() +// CHECK-DAG: call {{.*}} @_ZLW1AWP5Part26helperv() +// CHECK-DAG: ret i32 1 +// CHECK-DAG: ret i32 2 + +//--- part1.cppm +module; +static inline __attribute__((noinline)) int helper() { return 1; } +export module A:Part1; +export inline int part1() { return helper(); } + +//--- part2.cppm +module; +static inline __attribute__((noinline)) int helper() { return 2; } +export module A:Part2; +export inline int part2() { return helper(); } + +//--- A.cppm +export module A; +export import :Part1; +export import :Part2; + +//--- use.cpp +import A; +int use() { return part1() + part2(); } >From 0571efbe9495ecfc070b5aab9d75e9d8d0e9c034 Mon Sep 17 00:00:00 2001 From: cjc0013 <[email protected]> Date: Thu, 27 Aug 2026 19:45:26 -0400 Subject: [PATCH 2/2] [clang] Distinguish GMF internal functions across module units --- clang/lib/Serialization/ASTReaderDecl.cpp | 27 ++++++++++++++++--- ...lobal-module-fragment-internal-linkage.cpp | 22 ++++++++------- 2 files changed, 35 insertions(+), 14 deletions(-) diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp index 74e0106520011..0ff0472aacccb 100644 --- a/clang/lib/Serialization/ASTReaderDecl.cpp +++ b/clang/lib/Serialization/ASTReaderDecl.cpp @@ -3584,12 +3584,31 @@ ASTDeclReader::FindExistingResult ASTDeclReader::findExisting(NamedDecl *D) { } ASTContext &C = Reader.getContext(); + auto IsSameEntity = [&](NamedDecl *Existing) { + if (!C.isSameEntity(Existing, D)) + return false; + + auto *FD = dyn_cast<FunctionDecl>(D); + auto *ExistingFD = dyn_cast<FunctionDecl>(Existing); + if (!FD || !ExistingFD || + FD->getFormalLinkage() != Linkage::Internal || + ExistingFD->getFormalLinkage() != Linkage::Internal) + return true; + + Module *M = FD->getOwningModule(); + Module *ExistingM = ExistingFD->getOwningModule(); + if (!M || !ExistingM || !M->isGlobalModule() || + !ExistingM->isGlobalModule()) + return true; + + return M->getTopLevelModule() == ExistingM->getTopLevelModule(); + }; DeclContext *DC = D->getDeclContext()->getRedeclContext(); if (TypedefNameForLinkage) { auto It = Reader.ImportedTypedefNamesForLinkage.find( std::make_pair(DC, TypedefNameForLinkage)); if (It != Reader.ImportedTypedefNamesForLinkage.end()) - if (C.isSameEntity(It->second, D)) + if (IsSameEntity(It->second)) return FindExistingResult(Reader, D, It->second, AnonymousDeclNumber, TypedefNameForLinkage); // Go on to check in other places in case an existing typedef name @@ -3601,7 +3620,7 @@ ASTDeclReader::FindExistingResult ASTDeclReader::findExisting(NamedDecl *D) { // in its context by number. if (auto *Existing = getAnonymousDeclForMerging( Reader, D->getLexicalDeclContext(), AnonymousDeclNumber)) - if (C.isSameEntity(Existing, D)) + if (IsSameEntity(Existing)) return FindExistingResult(Reader, D, Existing, AnonymousDeclNumber, TypedefNameForLinkage); } else if (DC->isTranslationUnit() && @@ -3635,7 +3654,7 @@ ASTDeclReader::FindExistingResult ASTDeclReader::findExisting(NamedDecl *D) { if (NamedDecl *Existing = getDeclForMerging(*I, TypedefNameForLinkage, /*FilteringUsingShadowDecl=*/false)) - if (C.isSameEntity(Existing, D)) + if (IsSameEntity(Existing)) return FindExistingResult(Reader, D, Existing, AnonymousDeclNumber, TypedefNameForLinkage); } @@ -3644,7 +3663,7 @@ ASTDeclReader::FindExistingResult ASTDeclReader::findExisting(NamedDecl *D) { for (DeclContext::lookup_iterator I = R.begin(), E = R.end(); I != E; ++I) { if (NamedDecl *Existing = getDeclForMerging(*I, TypedefNameForLinkage, !isa<UsingShadowDecl>(D))) - if (C.isSameEntity(Existing, D)) { + if (IsSameEntity(Existing)) { return FindExistingResult(Reader, D, Existing, AnonymousDeclNumber, TypedefNameForLinkage); } diff --git a/clang/test/Modules/global-module-fragment-internal-linkage.cpp b/clang/test/Modules/global-module-fragment-internal-linkage.cpp index 5298015d92abe..c9fa548ddf6dd 100644 --- a/clang/test/Modules/global-module-fragment-internal-linkage.cpp +++ b/clang/test/Modules/global-module-fragment-internal-linkage.cpp @@ -8,21 +8,23 @@ // RUN: -emit-module-interface %t/part2.cppm -o %t/A-Part2.pcm // RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 \ // RUN: -emit-module-interface %t/A.cppm \ -// RUN: -fmodule-file=%t/A-Part1.pcm -fmodule-file=%t/A-Part2.pcm \ +// RUN: -fmodule-file=A:Part1=%t/A-Part1.pcm \ +// RUN: -fmodule-file=A:Part2=%t/A-Part2.pcm \ // RUN: -o %t/A.pcm // RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 -emit-llvm -o - \ // RUN: %t/use.cpp -fmodule-file=%t/A.pcm \ -// RUN: -fmodule-file=%t/A-Part1.pcm -fmodule-file=%t/A-Part2.pcm \ +// RUN: -fmodule-file=A:Part1=%t/A-Part1.pcm \ +// RUN: -fmodule-file=A:Part2=%t/A-Part2.pcm \ // RUN: | FileCheck %s // -// Two internal functions with the same ordinary mangled name must remain -// distinct when their global module fragments are imported together. -// CHECK-DAG: define internal {{.*}} @_ZLW1AWP5Part16helperv() -// CHECK-DAG: define internal {{.*}} @_ZLW1AWP5Part26helperv() -// CHECK-DAG: call {{.*}} @_ZLW1AWP5Part16helperv() -// CHECK-DAG: call {{.*}} @_ZLW1AWP5Part26helperv() +// Identical internal functions from the same textual header must remain +// distinct when separate global module fragments are imported together. +// CHECK-DAG: define internal {{.*}} @_ZW1AWP5Part1L6helperv() +// CHECK-DAG: define internal {{.*}} @_ZW1AWP5Part2L6helperv() +// CHECK-DAG: call {{.*}} @_ZW1AWP5Part1L6helperv() +// CHECK-DAG: call {{.*}} @_ZW1AWP5Part2L6helperv() +// CHECK-DAG: ret i32 1 // CHECK-DAG: ret i32 1 -// CHECK-DAG: ret i32 2 //--- part1.cppm module; @@ -32,7 +34,7 @@ export inline int part1() { return helper(); } //--- part2.cppm module; -static inline __attribute__((noinline)) int helper() { return 2; } +static inline __attribute__((noinline)) int helper() { return 1; } export module A:Part2; export inline int part2() { return helper(); } _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
