Author: Ilya Biryukov Date: 2025-08-04T10:12:52+02:00 New Revision: 0cfe9f7287f7c65d3539d39762815ed7497e06ac
URL: https://github.com/llvm/llvm-project/commit/0cfe9f7287f7c65d3539d39762815ed7497e06ac DIFF: https://github.com/llvm/llvm-project/commit/0cfe9f7287f7c65d3539d39762815ed7497e06ac.diff LOG: [Clang] Handle C++20 export declarations in -dump-minimization-hints (#151666) Thanks to Justin Stitt for bringing this up, providing test cases and a direction for the fix! Added: clang/test/Frontend/dump-minimization-hints-cpp20-modules.cpp Modified: clang/lib/Frontend/FrontendAction.cpp Removed: ################################################################################ diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp index 2d69f8cc21f96..a7d6a068fe2d0 100644 --- a/clang/lib/Frontend/FrontendAction.cpp +++ b/clang/lib/Frontend/FrontendAction.cpp @@ -84,29 +84,28 @@ class DeserializedDeclsSourceRangePrinter : public ASTConsumer, if (!IsCollectingDecls) return; if (!D || isa<TranslationUnitDecl>(D) || isa<LinkageSpecDecl>(D) || - isa<NamespaceDecl>(D)) { + isa<NamespaceDecl>(D) || isa<ExportDecl>(D)) { // These decls cover a lot of nested declarations that might not be used, // reducing the granularity and making the output less useful. return; } - auto *DC = D->getLexicalDeclContext(); - if (!DC || !DC->isFileContext()) { - // We choose to work at namespace level to reduce complexity and the - // number of cases we care about. + if (isa<ParmVarDecl>(D)) { + // Parameters are covered by their functions. return; } + auto *DC = D->getLexicalDeclContext(); + if (!DC || !shouldIncludeDeclsIn(DC)) + return; PendingDecls.push_back(D); - if (auto *NS = dyn_cast<NamespaceDecl>(DC)) { - // Add any namespaces we have not seen before. - // Note that we filter out namespaces from DeclRead as it includes too - // all redeclarations and we only want the ones that had other used - // declarations. - while (NS && ProcessedNamespaces.insert(NS).second) { - PendingDecls.push_back(NS); - - NS = dyn_cast<NamespaceDecl>(NS->getLexicalParent()); - } + for (; (isa<ExportDecl>(DC) || isa<NamespaceDecl>(DC)) && + ProcessedDeclContexts.insert(DC).second; + DC = DC->getLexicalParent()) { + // Add any interesting decl contexts that we have not seen before. + // Note that we filter them out from DeclRead as that would include all + // redeclarations of namespaces, potentially those that do not have any + // imported declarations. + PendingDecls.push_back(cast<Decl>(DC)); } } @@ -205,12 +204,38 @@ class DeserializedDeclsSourceRangePrinter : public ASTConsumer, private: std::vector<const Decl *> PendingDecls; - llvm::SmallPtrSet<const NamespaceDecl *, 0> ProcessedNamespaces; + llvm::SmallPtrSet<const DeclContext *, 0> ProcessedDeclContexts; bool IsCollectingDecls = true; const SourceManager &SM; std::unique_ptr<llvm::raw_ostream> OS; + static bool shouldIncludeDeclsIn(const DeclContext *DC) { + assert(DC && "DC is null"); + // We choose to work at namespace level to reduce complexity and the number + // of cases we care about. + // We still need to carefully handle composite declarations like + // `ExportDecl`. + for (; DC; DC = DC->getLexicalParent()) { + if (DC->isFileContext()) + return true; + if (isa<ExportDecl>(DC)) + continue; // Depends on the parent. + return false; + } + llvm_unreachable("DeclContext chain must end with a translation unit"); + } + llvm::SmallVector<CharSourceRange, 2> getRangesToMark(const Decl *D) { + if (auto *ED = dyn_cast<ExportDecl>(D)) { + if (!ED->hasBraces()) + return {SM.getExpansionRange(ED->getExportLoc())}; + + return {SM.getExpansionRange(SourceRange( + ED->getExportLoc(), + lexForLBrace(ED->getExportLoc(), D->getLangOpts()))), + SM.getExpansionRange(ED->getRBraceLoc())}; + } + auto *NS = dyn_cast<NamespaceDecl>(D); if (!NS) return {SM.getExpansionRange(D->getSourceRange())}; @@ -232,17 +257,7 @@ class DeserializedDeclsSourceRangePrinter : public ASTConsumer, } } } - auto &LangOpts = D->getLangOpts(); - // Now skip one token, the next should be the lbrace. - Token Tok; - if (Lexer::getRawToken(TokenBeforeLBrace, Tok, SM, LangOpts, true) || - Lexer::getRawToken(Tok.getEndLoc(), Tok, SM, LangOpts, true) || - Tok.getKind() != tok::l_brace) { - // On error or if we did not find the token we expected, avoid marking - // everything inside the namespace as used. - return {}; - } - LBraceLoc = Tok.getLocation(); + LBraceLoc = lexForLBrace(TokenBeforeLBrace, D->getLangOpts()); } return {SM.getExpansionRange(SourceRange(NS->getBeginLoc(), LBraceLoc)), SM.getExpansionRange(NS->getRBraceLoc())}; @@ -285,6 +300,20 @@ class DeserializedDeclsSourceRangePrinter : public ASTConsumer, OS->flush(); } + + SourceLocation lexForLBrace(SourceLocation TokenBeforeLBrace, + const LangOptions &LangOpts) { + // Now skip one token, the next should be the lbrace. + Token Tok; + if (Lexer::getRawToken(TokenBeforeLBrace, Tok, SM, LangOpts, true) || + Lexer::getRawToken(Tok.getEndLoc(), Tok, SM, LangOpts, true) || + Tok.getKind() != tok::l_brace) { + // On error or if we did not find the token we expected, avoid marking + // everything inside the namespace as used. + return SourceLocation(); + } + return Tok.getLocation(); + } }; /// Dumps deserialized declarations. diff --git a/clang/test/Frontend/dump-minimization-hints-cpp20-modules.cpp b/clang/test/Frontend/dump-minimization-hints-cpp20-modules.cpp new file mode 100644 index 0000000000000..a28acbacecfae --- /dev/null +++ b/clang/test/Frontend/dump-minimization-hints-cpp20-modules.cpp @@ -0,0 +1,117 @@ +// RUN: rm -rf %t +// RUN: mkdir -p %t +// RUN: split-file %s %t +// RUN: %clang_cc1 -std=c++20 %t/foo.cppm -emit-module-interface -o %t/foo.pcm +// RUN: %clang_cc1 -std=c++20 -fprebuilt-module-path=%t %t/use.cpp -dump-minimization-hints=%t/decls +// RUN: cat %t/decls +// RUN: cat %t/decls | FileCheck -check-prefix=RANGE %s +// RANGE:{ +// RANGE-NEXT:"required_ranges": [ +// RANGE-NEXT: { +// RANGE-NEXT: "file": "{{.+}}foo.cppm", +// RANGE-NEXT: "range": [ +// RANGE-NEXT: { +// RANGE-NEXT: "from": { +// RANGE-NEXT: "line": 3, +// RANGE-NEXT: "column": 1 +// RANGE-NEXT: }, +// RANGE-NEXT: "to": { +// RANGE-NEXT: "line": 3, +// RANGE-NEXT: "column": 22 +// RANGE-NEXT: } +// RANGE-NEXT: }, +// RANGE-NEXT: { +// RANGE-NEXT: "from": { +// RANGE-NEXT: "line": 4, +// RANGE-NEXT: "column": 3 +// RANGE-NEXT: }, +// RANGE-NEXT: "to": { +// RANGE-NEXT: "line": 4, +// RANGE-NEXT: "column": 9 +// RANGE-NEXT: } +// RANGE-NEXT: }, +// RANGE-NEXT: { +// RANGE-NEXT: "from": { +// RANGE-NEXT: "line": 4, +// RANGE-NEXT: "column": 10 +// RANGE-NEXT: }, +// RANGE-NEXT: "to": { +// RANGE-NEXT: "line": 4, +// RANGE-NEXT: "column": 43 +// RANGE-NEXT: } +// RANGE-NEXT: }, +// RANGE-NEXT: { +// RANGE-NEXT: "from": { +// RANGE-NEXT: "line": 6, +// RANGE-NEXT: "column": 1 +// RANGE-NEXT: }, +// RANGE-NEXT: "to": { +// RANGE-NEXT: "line": 6, +// RANGE-NEXT: "column": 2 +// RANGE-NEXT: } +// RANGE-NEXT: }, +// RANGE-NEXT: { +// RANGE-NEXT: "from": { +// RANGE-NEXT: "line": 8, +// RANGE-NEXT: "column": 1 +// RANGE-NEXT: }, +// RANGE-NEXT: "to": { +// RANGE-NEXT: "line": 8, +// RANGE-NEXT: "column": 7 +// RANGE-NEXT: } +// RANGE-NEXT: }, +// RANGE-NEXT: { +// RANGE-NEXT: "from": { +// RANGE-NEXT: "line": 8, +// RANGE-NEXT: "column": 8 +// RANGE-NEXT: }, +// RANGE-NEXT: "to": { +// RANGE-NEXT: "line": 8, +// RANGE-NEXT: "column": 25 +// RANGE-NEXT: } +// RANGE-NEXT: }, +// RANGE-NEXT: { +// RANGE-NEXT: "from": { +// RANGE-NEXT: "line": 9, +// RANGE-NEXT: "column": 3 +// RANGE-NEXT: }, +// RANGE-NEXT: "to": { +// RANGE-NEXT: "line": 9, +// RANGE-NEXT: "column": 36 +// RANGE-NEXT: } +// RANGE-NEXT: }, +// RANGE-NEXT: { +// RANGE-NEXT: "from": { +// RANGE-NEXT: "line": 11, +// RANGE-NEXT: "column": 1 +// RANGE-NEXT: }, +// RANGE-NEXT: "to": { +// RANGE-NEXT: "line": 11, +// RANGE-NEXT: "column": 2 +// RANGE-NEXT: } +// RANGE-NEXT: } +// RANGE-NEXT: ] +// RANGE-NEXT: } +// RANGE-NEXT:] +// RANGE-NEXT:} + +//--- foo.cppm +export module foo; + +namespace piecemeal { // line 3 + export int used(int n) { return n + 1; } + export int unused(int n) { return n + 2; } +} + +export namespace whole { // line 8 + int used(int n) { return n + 1; } + int unused(int n) { return n + 3; } +} // line 11 + +//--- use.cpp +import foo; + +int main() { + piecemeal::used(4); // only one of the functions used from each namespace. + whole::used(4); +} _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
