iains created this revision.
iains updated this revision to Diff 408755.
iains added a comment.
iains added reviewers: rsmith, urnathan, ChuanqiXu.
iains updated this revision to Diff 408803.
iains published this revision for review.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
Rebased onto other modules work.
iains added a comment.
repushing the rebase with clang-format available.
iains added a comment.
This is the first in a series of 8 patches to implement basic C++20 module
partition support in clang. This is an enabler, particularly in forming
diagnostics.
In C++20 modules imports must be together and at the start of the module.
Rather than growing more ad-hoc flags to test state, this keeps track of the
phase of of a valid module TU (first decl, global module frag, module,
private module frag). If the phasing is broken (with some diagnostic) the
pattern does not conform to a valid C++20 module, and we set the state
accordingly.
We can thus issue diagnostics when imports appear in the wrong places and
decouple the C++20 modules state from other module variants (modules-ts and
clang modules). Additionally, we attempt to diagnose wrong imports before
trying to find the module where possible (the latter will generally emit an
unhelpful diagnostic about the module not being available).
Although this generally simplifies the handling of C++20 module import
diagnostics, the motivation was that, in particular, it allows detecting
invalid imports like:
import module A;
int some_decl();
import module B;
where being in a module purview is insufficient to identify them.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D118893
Files:
clang/include/clang/Basic/DiagnosticParseKinds.td
clang/include/clang/Parse/Parser.h
clang/include/clang/Sema/Sema.h
clang/lib/Interpreter/IncrementalParser.cpp
clang/lib/Parse/ParseAST.cpp
clang/lib/Parse/ParseObjc.cpp
clang/lib/Parse/Parser.cpp
clang/lib/Sema/SemaModule.cpp
clang/test/Modules/cxx20-import-diagnostics-a.cpp
Index: clang/test/Modules/cxx20-import-diagnostics-a.cpp
===================================================================
--- /dev/null
+++ clang/test/Modules/cxx20-import-diagnostics-a.cpp
@@ -0,0 +1,127 @@
+// RUN: rm -rf %t
+// RUN: mkdir -p %t
+
+// RUN: %clang_cc1 -std=c++20 -emit-module-interface -D TU=0 -x c++ %s \
+// RUN: -o %t/B.pcm
+
+// RUN: %clang_cc1 -std=c++20 -emit-module-interface -D TU=1 -x c++ %s \
+// RUN: -o %t/C.pcm
+
+// RUN: %clang_cc1 -std=c++20 -emit-module-interface -D TU=2 -x c++ %s \
+// RUN: -fmodule-file=%t/B.pcm -fmodule-file=%t/C.pcm -o %t/AOK1.pcm
+
+// RUN: %clang_cc1 -std=c++20 -S -D TU=3 -x c++ %s \
+// RUN: -fmodule-file=%t/AOK1.pcm -o %t/tu_3.s -verify
+
+// RUN: %clang_cc1 -std=c++20 -emit-module-interface -D TU=4 -x c++ %s \
+// RUN: -fmodule-file=%t/B.pcm -fmodule-file=%t/C.pcm -o %t/BC.pcm -verify
+
+// RUN: %clang_cc1 -std=c++20 -S -D TU=5 -x c++ %s \
+// RUN: -fmodule-file=%t/B.pcm -fmodule-file=%t/C.pcm -o %t/tu_5.s -verify
+
+// RUN: %clang_cc1 -std=c++20 -emit-module-interface -D TU=6 -x c++ %s \
+// RUN: -fmodule-file=%t/B.pcm -o %t/D.pcm -verify
+
+// RUN: %clang_cc1 -std=c++20 -emit-module-interface -D TU=7 -x c++ %s \
+// RUN: -fmodule-file=%t/B.pcm -o %t/D.pcm -verify
+
+// RUN: %clang_cc1 -std=c++20 -S -D TU=8 -x c++ %s \
+// RUN: -fmodule-file=%t/B.pcm -o %t/tu_8.s -verify
+
+// RUN: %clang_cc1 -std=c++20 -emit-module-interface -D TU=9 -x c++ %s \
+// RUN: -o %t/B.pcm -verify
+
+// Test diagnostics for incorrect module import sequences.
+
+#if TU == 0
+
+export module B;
+
+int foo ();
+
+// expected-no-diagnostics
+
+#elif TU == 1
+
+export module C;
+
+int bar ();
+
+// expected-no-diagnostics
+
+#elif TU == 2
+
+export module AOK1;
+
+import B;
+export import C;
+
+export int theAnswer ();
+
+// expected-no-diagnostics
+
+#elif TU == 3
+
+module;
+
+module AOK1;
+
+export import C; // expected-error {{export declaration can only be used within a module interface unit}}
+
+int theAnswer () { return 42; }
+
+#elif TU == 4
+
+export module BC;
+
+export import B;
+
+int foo () { return 10; }
+
+import C; // expected-error {{imports must be contiguous and immediately follow the module declaration}}
+
+#elif TU == 5
+
+module B; // implicitly imports B.
+
+int foo () { return 10; }
+
+import C; // expected-error {{imports must be contiguous and immediately follow the module declaration}}
+
+#elif TU == 6
+
+module;
+// We can only have preprocessor commands here, which could include an include
+// translated header unit. However those are identified specifically by the
+// preprocessor; non-preprocessed user code should not contain an import here.
+import B; // expected-error {{module imports cannot be in the global module fragment}}
+
+export module D;
+
+int delta ();
+
+#elif TU == 7
+
+export module D;
+
+int delta ();
+
+module :private;
+
+import B; // expected-error {{module imports cannot be in the private module fragment}}
+
+#elif TU == 8
+
+module B;
+
+import B; // expected-error {{import of module 'B' appears within same top-level module 'B'}}
+
+#elif TU == 9
+
+export module B;
+
+import B; // expected-error {{import of module 'B' appears within same top-level module 'B'}}
+
+#else
+#error "no MODE set"
+#endif
Index: clang/lib/Sema/SemaModule.cpp
===================================================================
--- clang/lib/Sema/SemaModule.cpp
+++ clang/lib/Sema/SemaModule.cpp
@@ -82,10 +82,17 @@
Sema::DeclGroupPtrTy
Sema::ActOnModuleDecl(SourceLocation StartLoc, SourceLocation ModuleLoc,
- ModuleDeclKind MDK, ModuleIdPath Path, bool IsFirstDecl) {
+ ModuleDeclKind MDK, ModuleIdPath Path,
+ ModuleImportState &ImportState) {
assert((getLangOpts().ModulesTS || getLangOpts().CPlusPlusModules) &&
"should only have module decl in Modules TS or C++20");
+ bool IsFirstDecl = ImportState == ModuleImportState::FirstDecl;
+ bool SeenGMF = ImportState == ModuleImportState::GlobalFragment;
+ // If any of the steps here fail, we count that as invalidating C++20
+ // module state;
+ ImportState = ModuleImportState::NotACXX20Module;
+
// A module implementation unit requires that we are not compiling a module
// of any kind. A module interface unit requires that we are not compiling a
// module map.
@@ -136,7 +143,7 @@
// In C++20, the module-declaration must be the first declaration if there
// is no global module fragment.
- if (getLangOpts().CPlusPlusModules && !IsFirstDecl && !GlobalModuleFragment) {
+ if (getLangOpts().CPlusPlusModules && !IsFirstDecl && !SeenGMF) {
Diag(ModuleLoc, diag::err_module_decl_not_at_start);
SourceLocation BeginLoc =
ModuleScopes.empty()
@@ -231,6 +238,10 @@
TU->setModuleOwnershipKind(Decl::ModuleOwnershipKind::ModulePrivate);
TU->setLocalOwningModule(Mod);
+ // We are in the module purview, but before any other (non import)
+ // statements, so imports are allowed.
+ ImportState = ModuleImportState::ImportAllowed;
+
// FIXME: Create a ModuleDecl.
return nullptr;
}
@@ -301,10 +312,10 @@
SourceLocation ExportLoc,
SourceLocation ImportLoc,
ModuleIdPath Path) {
- // Flatten the module path for a Modules TS module name.
+ // Flatten the module path for a C++20 or Modules TS module name.
std::pair<IdentifierInfo *, SourceLocation> ModuleNameLoc;
- if (getLangOpts().ModulesTS) {
- std::string ModuleName;
+ std::string ModuleName;
+ if (getLangOpts().CPlusPlusModules || getLangOpts().ModulesTS) {
for (auto &Piece : Path) {
if (!ModuleName.empty())
ModuleName += ".";
@@ -314,6 +325,14 @@
Path = ModuleIdPath(ModuleNameLoc);
}
+ // Diagnose self-import before attempting a load.
+ if (getLangOpts().CPlusPlusModules && isCurrentModulePurview() &&
+ getCurrentModule()->Name == ModuleName) {
+ Diag(ImportLoc, diag::err_module_self_import) << ModuleName
+ << getLangOpts().CurrentModule;
+ return true;
+ }
+
Module *Mod =
getModuleLoader().loadModule(ImportLoc, Path, Module::AllVisible,
/*IsInclusionDirective=*/false);
@@ -342,11 +361,9 @@
// FIXME: we should support importing a submodule within a different submodule
// of the same top-level module. Until we do, make it an error rather than
// silently ignoring the import.
- // Import-from-implementation is valid in the Modules TS. FIXME: Should we
- // warn on a redundant import of the current module?
- // FIXME: Import of a module from an implementation partition of the same
- // module is permitted.
- if (Mod->getTopLevelModuleName() == getLangOpts().CurrentModule &&
+ // FIXME: Should we warn on a redundant import of the current module?
+ if (!getLangOpts().CPlusPlusModules &&
+ Mod->getTopLevelModuleName() == getLangOpts().CurrentModule &&
(getLangOpts().isCompilingModule() || !getLangOpts().ModulesTS)) {
Diag(ImportLoc, getLangOpts().isCompilingModule()
? diag::err_module_self_import
Index: clang/lib/Parse/Parser.cpp
===================================================================
--- clang/lib/Parse/Parser.cpp
+++ clang/lib/Parse/Parser.cpp
@@ -581,15 +581,20 @@
/// top-level-declaration-seq[opt] private-module-fragment[opt]
///
/// Note that in C, it is an error if there is no first declaration.
-bool Parser::ParseFirstTopLevelDecl(DeclGroupPtrTy &Result) {
+bool Parser::ParseFirstTopLevelDecl(DeclGroupPtrTy &Result,
+ Sema::ModuleImportState &ImportState) {
Actions.ActOnStartOfTranslationUnit();
+ // For C++20 modules, a module decl must be the first in the TU. We also
+ // need to track module imports.
+ ImportState = Sema::ModuleImportState::FirstDecl;
+ bool NoTopLevelDecls = ParseTopLevelDecl(Result, ImportState);
+
// C11 6.9p1 says translation units must have at least one top-level
// declaration. C++ doesn't have this restriction. We also don't want to
// complain if we have a precompiled header, although technically if the PCH
// is empty we should still emit the (pedantic) diagnostic.
// If the main file is a header, we're only pretending it's a TU; don't warn.
- bool NoTopLevelDecls = ParseTopLevelDecl(Result, true);
if (NoTopLevelDecls && !Actions.getASTContext().getExternalSource() &&
!getLangOpts().CPlusPlus && !getLangOpts().IsHeaderFile)
Diag(diag::ext_empty_translation_unit);
@@ -603,7 +608,8 @@
/// top-level-declaration:
/// declaration
/// [C++20] module-import-declaration
-bool Parser::ParseTopLevelDecl(DeclGroupPtrTy &Result, bool IsFirstDecl) {
+bool Parser::ParseTopLevelDecl(DeclGroupPtrTy &Result,
+ Sema::ModuleImportState &ImportState) {
DestroyTemplateIdAnnotationsRAIIObj CleanupRAII(*this);
// Skip over the EOF token, flagging end of previous input for incremental
@@ -647,13 +653,12 @@
case tok::kw_module:
module_decl:
- Result = ParseModuleDecl(IsFirstDecl);
+ Result = ParseModuleDecl(ImportState);
return false;
- // tok::kw_import is handled by ParseExternalDeclaration. (Under the Modules
- // TS, an import can occur within an export block.)
+ case tok::kw_import:
import_decl: {
- Decl *ImportDecl = ParseModuleImport(SourceLocation());
+ Decl *ImportDecl = ParseModuleImport(SourceLocation(), ImportState);
Result = Actions.ConvertDeclToDeclGroup(ImportDecl);
return false;
}
@@ -669,12 +674,14 @@
Actions.ActOnModuleBegin(Tok.getLocation(), reinterpret_cast<Module *>(
Tok.getAnnotationValue()));
ConsumeAnnotationToken();
+ ImportState = Sema::ModuleImportState::NotACXX20Module;
return false;
case tok::annot_module_end:
Actions.ActOnModuleEnd(Tok.getLocation(), reinterpret_cast<Module *>(
Tok.getAnnotationValue()));
ConsumeAnnotationToken();
+ ImportState = Sema::ModuleImportState::NotACXX20Module;
return false;
case tok::eof:
@@ -718,6 +725,16 @@
MaybeParseCXX11Attributes(attrs);
Result = ParseExternalDeclaration(attrs);
+ // An empty Result might mean a line with ';' or some parsing error, ignore
+ // it.
+ if (Result) {
+ if(ImportState == Sema::ModuleImportState::FirstDecl)
+ // First decl was not modular.
+ ImportState = Sema::ModuleImportState::NotACXX20Module;
+ else if (ImportState == Sema::ModuleImportState::ImportAllowed)
+ // Non-imports disallow further imports.
+ ImportState = Sema::ModuleImportState::ImportFinished;
+ }
return false;
}
@@ -888,10 +905,18 @@
CurParsedObjCImpl ? Sema::PCC_ObjCImplementation : Sema::PCC_Namespace);
return nullptr;
case tok::kw_import:
- SingleDecl = ParseModuleImport(SourceLocation());
+ {
+ Sema::ModuleImportState IS = Sema::ModuleImportState::NotACXX20Module;
+ if (getLangOpts().CPlusPlusModules) {
+ llvm_unreachable ("not expecting a c++20 import here");
+ ProhibitAttributes(attrs);
+ }
+ SingleDecl = ParseModuleImport(SourceLocation(), IS);
+ }
break;
case tok::kw_export:
if (getLangOpts().CPlusPlusModules || getLangOpts().ModulesTS) {
+ ProhibitAttributes(attrs);
SingleDecl = ParseExportDeclaration();
break;
}
@@ -2291,7 +2316,7 @@
/// attribute-specifier-seq[opt] ';'
/// private-module-fragment: [C++2a]
/// 'module' ':' 'private' ';' top-level-declaration-seq[opt]
-Parser::DeclGroupPtrTy Parser::ParseModuleDecl(bool IsFirstDecl) {
+Parser::DeclGroupPtrTy Parser::ParseModuleDecl(Sema::ModuleImportState &ImportState) {
SourceLocation StartLoc = Tok.getLocation();
Sema::ModuleDeclKind MDK = TryConsumeToken(tok::kw_export)
@@ -2311,7 +2336,7 @@
// Parse a global-module-fragment, if present.
if (getLangOpts().CPlusPlusModules && Tok.is(tok::semi)) {
SourceLocation SemiLoc = ConsumeToken();
- if (!IsFirstDecl) {
+ if (ImportState != Sema::ModuleImportState::FirstDecl) {
Diag(StartLoc, diag::err_global_module_introducer_not_at_start)
<< SourceRange(StartLoc, SemiLoc);
return nullptr;
@@ -2320,6 +2345,7 @@
Diag(StartLoc, diag::err_module_fragment_exported)
<< /*global*/0 << FixItHint::CreateRemoval(StartLoc);
}
+ ImportState = Sema::ModuleImportState::GlobalFragment;
return Actions.ActOnGlobalModuleFragmentDecl(ModuleLoc);
}
@@ -2334,6 +2360,7 @@
SourceLocation PrivateLoc = ConsumeToken();
DiagnoseAndSkipCXX11Attributes();
ExpectAndConsumeSemi(diag::err_private_module_fragment_expected_semi);
+ ImportState = Sema::ModuleImportState::PrivateFragment;
return Actions.ActOnPrivateModuleFragmentDecl(ModuleLoc, PrivateLoc);
}
@@ -2361,7 +2388,7 @@
ExpectAndConsumeSemi(diag::err_module_expected_semi);
- return Actions.ActOnModuleDecl(StartLoc, ModuleLoc, MDK, Path, IsFirstDecl);
+ return Actions.ActOnModuleDecl(StartLoc, ModuleLoc, MDK, Path, ImportState);
}
/// Parse a module import declaration. This is essentially the same for
@@ -2379,7 +2406,8 @@
/// attribute-specifier-seq[opt] ';'
/// 'export'[opt] 'import' header-name
/// attribute-specifier-seq[opt] ';'
-Decl *Parser::ParseModuleImport(SourceLocation AtLoc) {
+Decl *Parser::ParseModuleImport(SourceLocation AtLoc,
+ Sema::ModuleImportState &ImportState) {
SourceLocation StartLoc = AtLoc.isInvalid() ? Tok.getLocation() : AtLoc;
SourceLocation ExportLoc;
@@ -2428,6 +2456,42 @@
return nullptr;
}
+ // Diagnose mis-imports.
+ bool SeenError = true;
+ switch (ImportState) {
+ case Sema::ModuleImportState::ImportAllowed:
+ SeenError = false;
+ break;
+ case Sema::ModuleImportState::FirstDecl:
+ case Sema::ModuleImportState::NotACXX20Module:
+ // These cases will be an error when partitions are implemented.
+ SeenError = false;
+ break;
+ case Sema::ModuleImportState::GlobalFragment:
+ // We can only have pre-processor directives in the global module
+ // fragment. We can, however have a header unit import here.
+ if(!HeaderUnit)
+ // We do not have partition support yet.
+ Diag(ImportLoc, diag::err_import_in_global_fragment) << 0;
+ else
+ SeenError = false;
+ break;
+ case Sema::ModuleImportState::ImportFinished:
+ if(getLangOpts().CPlusPlusModules)
+ Diag(ImportLoc, diag::err_import_not_allowed_here);
+ else
+ SeenError = false;
+ break;
+ case Sema::ModuleImportState::PrivateFragment:
+ // We do not have partition support yet.
+ Diag(ImportLoc, diag::err_import_in_private_fragment) << 0;
+ break;
+ }
+ if (SeenError) {
+ ExpectAndConsumeSemi(diag::err_module_expected_semi);
+ return nullptr;
+ }
+
DeclResult Import;
if (HeaderUnit)
Import =
Index: clang/lib/Parse/ParseObjc.cpp
===================================================================
--- clang/lib/Parse/ParseObjc.cpp
+++ clang/lib/Parse/ParseObjc.cpp
@@ -79,7 +79,8 @@
break;
case tok::objc_import:
if (getLangOpts().Modules || getLangOpts().DebuggerSupport) {
- SingleDecl = ParseModuleImport(AtLoc);
+ Sema::ModuleImportState IS = Sema::ModuleImportState::NotACXX20Module;
+ SingleDecl = ParseModuleImport(AtLoc, IS);
break;
}
Diag(AtLoc, diag::err_atimport);
Index: clang/lib/Parse/ParseAST.cpp
===================================================================
--- clang/lib/Parse/ParseAST.cpp
+++ clang/lib/Parse/ParseAST.cpp
@@ -154,8 +154,9 @@
llvm::TimeTraceScope TimeScope("Frontend");
P.Initialize();
Parser::DeclGroupPtrTy ADecl;
- for (bool AtEOF = P.ParseFirstTopLevelDecl(ADecl); !AtEOF;
- AtEOF = P.ParseTopLevelDecl(ADecl)) {
+ Sema::ModuleImportState ImportState;
+ for (bool AtEOF = P.ParseFirstTopLevelDecl(ADecl, ImportState); !AtEOF;
+ AtEOF = P.ParseTopLevelDecl(ADecl, ImportState)) {
// If we got a null return and something *was* parsed, ignore it. This
// is due to a top-level semicolon, an action override, or a parse error
// skipping something.
Index: clang/lib/Interpreter/IncrementalParser.cpp
===================================================================
--- clang/lib/Interpreter/IncrementalParser.cpp
+++ clang/lib/Interpreter/IncrementalParser.cpp
@@ -164,8 +164,9 @@
}
Parser::DeclGroupPtrTy ADecl;
- for (bool AtEOF = P->ParseFirstTopLevelDecl(ADecl); !AtEOF;
- AtEOF = P->ParseTopLevelDecl(ADecl)) {
+ Sema::ModuleImportState ImportState;
+ for (bool AtEOF = P->ParseFirstTopLevelDecl(ADecl, ImportState); !AtEOF;
+ AtEOF = P->ParseTopLevelDecl(ADecl, ImportState)) {
// If we got a null return and something *was* parsed, ignore it. This
// is due to a top-level semicolon, an action override, or a parse error
// skipping something.
Index: clang/include/clang/Sema/Sema.h
===================================================================
--- clang/include/clang/Sema/Sema.h
+++ clang/include/clang/Sema/Sema.h
@@ -2949,11 +2949,23 @@
Implementation, ///< 'module X;'
};
+ /// An enumeration to represent the transition of states in parsing module
+ /// fragments and imports.
+ enum class ModuleImportState {
+ FirstDecl,
+ GlobalFragment,
+ ImportAllowed,
+ ImportFinished,
+ PrivateFragment,
+ NotACXX20Module
+ };
+
/// The parser has processed a module-declaration that begins the definition
/// of a module interface or implementation.
DeclGroupPtrTy ActOnModuleDecl(SourceLocation StartLoc,
SourceLocation ModuleLoc, ModuleDeclKind MDK,
- ModuleIdPath Path, bool IsFirstDecl);
+ ModuleIdPath Path,
+ ModuleImportState &ImportState);
/// The parser has processed a global-module-fragment declaration that begins
/// the definition of the global module fragment of the current module unit.
Index: clang/include/clang/Parse/Parser.h
===================================================================
--- clang/include/clang/Parse/Parser.h
+++ clang/include/clang/Parse/Parser.h
@@ -464,14 +464,17 @@
void Initialize();
/// Parse the first top-level declaration in a translation unit.
- bool ParseFirstTopLevelDecl(DeclGroupPtrTy &Result);
+ bool ParseFirstTopLevelDecl(DeclGroupPtrTy &Result,
+ Sema::ModuleImportState &ImportState);
/// ParseTopLevelDecl - Parse one top-level declaration. Returns true if
/// the EOF was encountered.
- bool ParseTopLevelDecl(DeclGroupPtrTy &Result, bool IsFirstDecl = false);
+ bool ParseTopLevelDecl(DeclGroupPtrTy &Result,
+ Sema::ModuleImportState &ImportState);
bool ParseTopLevelDecl() {
DeclGroupPtrTy Result;
- return ParseTopLevelDecl(Result);
+ Sema::ModuleImportState IS = Sema::ModuleImportState::NotACXX20Module;
+ return ParseTopLevelDecl(Result, IS);
}
/// ConsumeToken - Consume the current 'peek token' and lex the next one.
@@ -3489,8 +3492,8 @@
//===--------------------------------------------------------------------===//
// Modules
- DeclGroupPtrTy ParseModuleDecl(bool IsFirstDecl);
- Decl *ParseModuleImport(SourceLocation AtLoc);
+ DeclGroupPtrTy ParseModuleDecl(Sema::ModuleImportState &ImportState);
+ Decl *ParseModuleImport(SourceLocation AtLoc, Sema::ModuleImportState &ImportState);
bool parseMisplacedModuleImport();
bool tryParseMisplacedModuleImport() {
tok::TokenKind Kind = Tok.getKind();
Index: clang/include/clang/Basic/DiagnosticParseKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticParseKinds.td
+++ clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -1539,6 +1539,12 @@
def err_missing_before_module_end : Error<"expected %0 at end of module">;
def err_unsupported_module_partition : Error<
"sorry, module partitions are not yet supported">;
+def err_import_not_allowed_here : Error<
+ "imports must be contiguous and immediately follow the module declaration">;
+def err_import_in_global_fragment : Error<
+ "module%select{| partition}0 imports cannot be in the global module fragment">;
+def err_import_in_private_fragment : Error<
+ "module%select{| partition}0 imports cannot be in the private module fragment">;
def err_export_empty : Error<"export declaration cannot be empty">;
}
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
