https://github.com/balazske created https://github.com/llvm/llvm-project/pull/204188
Names with "weak" link attribute can have a definition in multiple source files. The externalDefMap file used at CTU analysis did not contain information about this and using more (weak) definitions with same name was indicated as error. Format of the externalDefMap file is changed in a way that the USR string contains a '-' character at the begin if the symbol is weak (this is counted in the USR-length value). At non-weak symbols the format remains unchanged. At reading the definitions, one of the weak symbols is chosen if there is no "strong" definition, otherwise the "strong" is used, and multiple "strong" definitions are error (like before). From 7af44726ea38d34cb8f2d99bc9e40223bdf0323d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bal=C3=A1zs=20K=C3=A9ri?= <[email protected]> Date: Tue, 16 Jun 2026 17:50:58 +0200 Subject: [PATCH] [clang][CrossTU] Indicate weak link attribute in ExternalDefMap. Names with "weak" link attribute can have a definition in multiple source files. The externalDefMap file used at CTU analysis did not contain information about this and using more (weak) definitions with same name was indicated as error. Format of the externalDefMap file is changed in a way that the USR string contains a '-' character at the begin if the symbol is weak (this is counted in the USR-length value). At non-weak symbols the format remains unchanged. At reading the definitions, one of the weak symbols is chosen if there is no "strong" definition, otherwise the "strong" is used, and multiple "strong" definitions are error (like before). --- clang/lib/CrossTU/CrossTranslationUnit.cpp | 41 +++++++++++++++++---- clang/test/Analysis/ctu/test-weak-sym-1.c | 42 ++++++++++++++++++++++ clang/test/Analysis/ctu/test-weak-sym-2.c | 42 ++++++++++++++++++++++ 3 files changed, 119 insertions(+), 6 deletions(-) create mode 100644 clang/test/Analysis/ctu/test-weak-sym-1.c create mode 100644 clang/test/Analysis/ctu/test-weak-sym-2.c diff --git a/clang/lib/CrossTU/CrossTranslationUnit.cpp b/clang/lib/CrossTU/CrossTranslationUnit.cpp index 248c6320bc61b..5773e4d2a7813 100644 --- a/clang/lib/CrossTU/CrossTranslationUnit.cpp +++ b/clang/lib/CrossTU/CrossTranslationUnit.cpp @@ -179,9 +179,13 @@ std::error_code IndexError::convertToErrorCode() const { /// /// @param[in] LineRef The input CTU index item in format /// "<USR-Length>:<USR> <File-Path>". -/// @param[out] LookupName The lookup name in format "<USR-Length>:<USR>". +/// <USR> may contain a '-' at the start which indicates +/// that the symbol is weak. +/// @param[out] IsWeak The weakness status of the symbol. +/// @param[out] LookupName The lookup name in format "<USR-Length>:<USR>". The +/// optional '-' is removed from it. /// @param[out] FilePath The file path "<File-Path>". -static bool parseCrossTUIndexItem(StringRef LineRef, StringRef &LookupName, +static bool parseCrossTUIndexItem(StringRef LineRef, bool &IsWeak, StringRef &LookupName, StringRef &FilePath) { // `LineRef` is "<USR-Length>:<USR> <File-Path>" now. @@ -199,6 +203,16 @@ static bool parseCrossTUIndexItem(StringRef LineRef, StringRef &LookupName, if (USRLength >= LineRef.size() || ' ' != LineRef[USRLength]) return false; + // The first character of this USR can be a '-' to indicate weakness of the + // symbol. The input USR-length includes this character, it is removed from + // the result. + char MaybeWeak = LineRef.front(); + IsWeak = MaybeWeak == '-'; + if (IsWeak) { + LineRef.consume_front(MaybeWeak); + --USRLength; + } + LookupName = LineRef.substr(0, USRLength); FilePath = LineRef.substr(USRLength + 1); return true; @@ -212,12 +226,14 @@ parseCrossTUIndex(StringRef IndexPath) { IndexPath.str()); llvm::StringMap<std::string> Result; + llvm::StringSet<> WeakSyms; std::string Line; unsigned LineNo = 1; while (std::getline(ExternalMapFile, Line)) { // Split lookup name and file path StringRef LookupName, FilePathInIndex; - if (!parseCrossTUIndexItem(Line, LookupName, FilePathInIndex)) + bool IsWeak; + if (!parseCrossTUIndexItem(Line, IsWeak, LookupName, FilePathInIndex)) return llvm::make_error<IndexError>( index_error_code::invalid_index_format, IndexPath.str(), LineNo); @@ -228,9 +244,20 @@ parseCrossTUIndex(StringRef IndexPath) { bool InsertionOccurred; std::tie(std::ignore, InsertionOccurred) = Result.try_emplace(LookupName, FilePath.begin(), FilePath.end()); - if (!InsertionOccurred) - return llvm::make_error<IndexError>( - index_error_code::multiple_definitions, IndexPath.str(), LineNo); + if (!InsertionOccurred) { + if (!IsWeak) { + if (!WeakSyms.contains(LookupName)) { + return llvm::make_error<IndexError>( + index_error_code::multiple_definitions, IndexPath.str(), LineNo); + } else { + Result[LookupName].assign(FilePath.begin(), FilePath.end()); + WeakSyms.erase(LookupName); + } + } + } else { + if (IsWeak) + WeakSyms.insert(LookupName); + } ++LineNo; } @@ -279,6 +306,8 @@ CrossTranslationUnitContext::~CrossTranslationUnitContext() {} std::optional<std::string> CrossTranslationUnitContext::getLookupName(const Decl *D) { SmallString<128> DeclUSR; + if (D->hasAttr<WeakAttr>()) + DeclUSR.push_back('-'); bool Ret = index::generateUSRForDecl(D, DeclUSR); if (Ret) return {}; diff --git a/clang/test/Analysis/ctu/test-weak-sym-1.c b/clang/test/Analysis/ctu/test-weak-sym-1.c new file mode 100644 index 0000000000000..602f9aa2f752f --- /dev/null +++ b/clang/test/Analysis/ctu/test-weak-sym-1.c @@ -0,0 +1,42 @@ +// RUN: rm -rf %t +// RUN: mkdir -p %t +// RUN: split-file %s %t + +// RUN: %clang_cc1 -x c -emit-pch -o %t/a.c.ast %t/a.c +// RUN: %clang_cc1 -x c -emit-pch -o %t/b.c.ast %t/b.c + +// RUN: %clang_extdef_map %t/a.c %t/b.c -- -c -x c > %t/externalDefMap.tmp1.txt +// RUN: sed -e 's|\.c$|.c.ast|g' %t/externalDefMap.tmp1.txt > %t/externalDefMap.tmp2.txt +// RUN: sed -e 's|%t\/||g' %t/externalDefMap.tmp2.txt > %t/externalDefMap.txt + +// RUN: %clang_cc1 -analyze \ +// RUN: -analyzer-checker=core \ +// RUN: -analyzer-config experimental-enable-naive-ctu-analysis=true \ +// RUN: -analyzer-config display-ctu-progress=true \ +// RUN: -analyzer-config ctu-dir=%t \ +// RUN: -verify %t/main.c 2>&1 | FileCheck %s + +//--- main.c + +// expected-no-diagnostics +// CHECK: CTU loaded AST file: b.c.ast + +int fn(void); + +int main(int argc, char* argv[]) { + return fn(); +} + +//--- a.c + +int fn(void) __attribute__((weak)); + +int fn(void) { + return 1; +} + +//--- b.c + +int fn(void) { + return 0; +} diff --git a/clang/test/Analysis/ctu/test-weak-sym-2.c b/clang/test/Analysis/ctu/test-weak-sym-2.c new file mode 100644 index 0000000000000..6335f38867e00 --- /dev/null +++ b/clang/test/Analysis/ctu/test-weak-sym-2.c @@ -0,0 +1,42 @@ +// RUN: rm -rf %t +// RUN: mkdir -p %t +// RUN: split-file %s %t + +// RUN: %clang_cc1 -x c -emit-pch -o %t/a.c.ast %t/a.c +// RUN: %clang_cc1 -x c -emit-pch -o %t/b.c.ast %t/b.c + +// RUN: %clang_extdef_map %t/a.c %t/b.c -- -c -x c > %t/externalDefMap.tmp1.txt +// RUN: sed -e 's|\.c$|.c.ast|g' %t/externalDefMap.tmp1.txt > %t/externalDefMap.tmp2.txt +// RUN: sed -e 's|%t\/||g' %t/externalDefMap.tmp2.txt > %t/externalDefMap.txt + +// RUN: %clang_cc1 -analyze \ +// RUN: -analyzer-checker=core \ +// RUN: -analyzer-config experimental-enable-naive-ctu-analysis=true \ +// RUN: -analyzer-config display-ctu-progress=true \ +// RUN: -analyzer-config ctu-dir=%t \ +// RUN: -verify %t/main.c 2>&1 | FileCheck %s + +//--- main.c + +// expected-no-diagnostics +// CHECK: CTU loaded AST file: a.c.ast + +int fn(void); + +int main(int argc, char* argv[]) { + return fn(); +} + +//--- a.c + +int fn(void) { + return 1; +} + +//--- b.c + +int fn(void) __attribute__((weak)); + +int fn(void) { + return 0; +} _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
