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[C++20] [Modules] Don't check input files for C++20 Modules

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Close https://github.com/llvm/llvm-project/issues/62269

Currently, the compiler will emit errors when we compile C++20 modules
if the referenced files changed or got removed. This is because we reuse
the existing logic from Clang implicit modules. It is helpful for clang
implicit modules since it is implicit and we want to be sure things
don't go wrong. But it is not necessary for C++20 modules. The C++20
modules is explicit and it is build systems' responsibility to maintain
the dependencies. So the check in the compiler side may be an overkill.
This commit is contained in:
Chuanqi Xu 2023-05-06 11:10:43 +08:00
parent a29a97d76b
commit 5b388f86aa
4 changed files with 80 additions and 14 deletions
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3
clang/include/clang/Serialization/ModuleFile.h
View File

@ -164,6 +164,9 @@ public:
/// Whether this precompiled header is a relocatable PCH file.
bool RelocatablePCH = false;
/// Whether this mdoule file is a standard c++ module.
bool StandardCXXModule = false;
/// Whether timestamps are included in this module file.
bool HasTimestamps = false;

15
clang/lib/Serialization/ASTReader.cpp
View File

@ -2389,12 +2389,15 @@ InputFile ASTReader::getInputFile(ModuleFile &F, unsigned ID, bool Complain) {
StringRef Filename = FI.Filename;
uint64_t StoredContentHash = FI.ContentHash;
// For standard C++ modules, we don't need to check the inputs.
bool SkipChecks = F.StandardCXXModule;
OptionalFileEntryRefDegradesToFileEntryPtr File = OptionalFileEntryRef(
expectedToOptional(FileMgr.getFileRef(Filename, /*OpenFile=*/false)));
// For an overridden file, create a virtual file with the stored
// size/timestamp.
if ((Overridden || Transient) && !File)
if ((Overridden || Transient || SkipChecks) && !File)
File = FileMgr.getVirtualFileRef(Filename, StoredSize, StoredTime);
if (!File) {
@ -2417,7 +2420,7 @@ InputFile ASTReader::getInputFile(ModuleFile &F, unsigned ID, bool Complain) {
// PCH.
SourceManager &SM = getSourceManager();
// FIXME: Reject if the overrides are different.
if ((!Overridden && !Transient) && SM.isFileOverridden(File)) {
if ((!Overridden && !Transient) && !SkipChecks && SM.isFileOverridden(File)) {
if (Complain)
Error(diag::err_fe_pch_file_overridden, Filename);
@ -2476,7 +2479,7 @@ InputFile ASTReader::getInputFile(ModuleFile &F, unsigned ID, bool Complain) {
};
bool IsOutOfDate = false;
auto FileChange = HasInputFileChanged();
auto FileChange = SkipChecks ? Change{Change::None} : HasInputFileChanged();
// For an overridden file, there is nothing to validate.
if (!Overridden && FileChange.Kind != Change::None) {
if (Complain && !Diags.isDiagnosticInFlight()) {
@ -2821,7 +2824,7 @@ ASTReader::ReadControlBlock(ModuleFile &F,
return VersionMismatch;
}
bool hasErrors = Record[6];
bool hasErrors = Record[7];
if (hasErrors && !DisableValidation) {
// If requested by the caller and the module hasn't already been read
// or compiled, mark modules on error as out-of-date.
@ -2845,7 +2848,9 @@ ASTReader::ReadControlBlock(ModuleFile &F,
if (F.RelocatablePCH)
F.BaseDirectory = isysroot.empty() ? "/" : isysroot;
F.HasTimestamps = Record[5];
F.StandardCXXModule = Record[5];
F.HasTimestamps = Record[6];
const std::string &CurBranch = getClangFullRepositoryVersion();
StringRef ASTBranch = Blob;

20
clang/lib/Serialization/ASTWriter.cpp
View File

@ -1243,6 +1243,8 @@ void ASTWriter::WriteControlBlock(Preprocessor &PP, ASTContext &Context,
MetadataAbbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 16)); // Clang maj.
MetadataAbbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 16)); // Clang min.
MetadataAbbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Relocatable
// Standard C++ module
MetadataAbbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
MetadataAbbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Timestamps
MetadataAbbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // Errors
MetadataAbbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob)); // SVN branch/tag
@ -1250,15 +1252,15 @@ void ASTWriter::WriteControlBlock(Preprocessor &PP, ASTContext &Context,
assert((!WritingModule || isysroot.empty()) &&
"writing module as a relocatable PCH?");
{
RecordData::value_type Record[] = {
METADATA,
VERSION_MAJOR,
VERSION_MINOR,
CLANG_VERSION_MAJOR,
CLANG_VERSION_MINOR,
!isysroot.empty(),
IncludeTimestamps,
ASTHasCompilerErrors};
RecordData::value_type Record[] = {METADATA,
VERSION_MAJOR,
VERSION_MINOR,
CLANG_VERSION_MAJOR,
CLANG_VERSION_MINOR,
!isysroot.empty(),
isWritingStdCXXNamedModules(),
IncludeTimestamps,
ASTHasCompilerErrors};
Stream.EmitRecordWithBlob(MetadataAbbrevCode, Record,
getClangFullRepositoryVersion());
}

56
clang/test/Modules/cxx20-no-check-input.cppm Normal file
View File

@ -0,0 +1,56 @@
// RUN: rm -rf %t
// RUN: split-file %s %t
// RUN: cd %t
//
// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple \
// RUN: %t/a.cppm -emit-module-interface -o %t/a.pcm
// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple \
// RUN: %t/use.cpp -fmodule-file=a=%t/a.pcm -verify -fsyntax-only
// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple \
// RUN: %t/a.pcm -emit-llvm -o - | FileCheck %t/a.ll
//
// RUN: echo "//Update" >> %t/foo.h
// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple \
// RUN: %t/use.cpp -fmodule-file=a=%t/a.pcm -verify -fsyntax-only
// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple \
// RUN: %t/a.pcm -emit-llvm -o - | FileCheck %t/a.ll
//
// RUN: echo "//Update" >> %t/a.cppm
// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple \
// RUN: %t/use.cpp -fmodule-file=a=%t/a.pcm -verify -fsyntax-only
// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple \
// RUN: %t/a.pcm -emit-llvm -o - | FileCheck %t/a.ll
//
// RUN: rm -f %t/foo.h
// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple \
// RUN: %t/use.cpp -fmodule-file=a=%t/a.pcm -verify -fsyntax-only
// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple \
// RUN: %t/a.pcm -emit-llvm -o - | FileCheck %t/a.ll
//
// RUN: rm -f %t/a.cppm
// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple \
// RUN: %t/use.cpp -fmodule-file=a=%t/a.pcm -verify -fsyntax-only
// RUN: %clang_cc1 -std=c++20 -triple %itanium_abi_triple \
// RUN: %t/a.pcm -emit-llvm -o - | FileCheck %t/a.ll
//--- foo.h
inline int foo = 43;
//--- a.cppm
// expected-no-diagnostics
module;
#include "foo.h"
export module a;
export using ::foo;
//--- a.ll
// check the LLVM IR are generated succesfully.
// CHECK: define{{.*}}@_ZGIW1a
//--- use.cpp
// expected-no-diagnostics
import a;
int use() {
return foo;
}