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-rw-r--r--clang/include/clang/AST/Decl.h5
-rw-r--r--clang/include/clang/AST/ExternalASTSource.h16
-rw-r--r--clang/include/clang/Sema/MultiplexExternalSemaSource.h2
-rw-r--r--clang/include/clang/Serialization/ASTReader.h8
-rw-r--r--clang/lib/AST/ASTContext.cpp4
-rw-r--r--clang/lib/AST/Decl.cpp24
-rw-r--r--clang/lib/Sema/MultiplexExternalSemaSource.cpp8
-rw-r--r--clang/lib/Serialization/ASTReader.cpp4
-rw-r--r--clang/lib/Serialization/ASTReaderDecl.cpp3
-rw-r--r--clang/lib/Serialization/ASTWriterDecl.cpp14
-rw-r--r--clang/test/Modules/var-init-side-effects.cpp37
11 files changed, 116 insertions, 9 deletions
diff --git a/clang/include/clang/AST/Decl.h b/clang/include/clang/AST/Decl.h
index 05aac15..23cd25e 100644
--- a/clang/include/clang/AST/Decl.h
+++ b/clang/include/clang/AST/Decl.h
@@ -1352,6 +1352,11 @@ public:
return const_cast<VarDecl *>(this)->getInitializingDeclaration();
}
+ /// Checks whether this declaration has an initializer with side effects,
+ /// without triggering deserialization if the initializer is not yet
+ /// deserialized.
+ bool hasInitWithSideEffects() const;
+
/// Determine whether this variable's value might be usable in a
/// constant expression, according to the relevant language standard.
/// This only checks properties of the declaration, and does not check
diff --git a/clang/include/clang/AST/ExternalASTSource.h b/clang/include/clang/AST/ExternalASTSource.h
index f45e3af..e91d513 100644
--- a/clang/include/clang/AST/ExternalASTSource.h
+++ b/clang/include/clang/AST/ExternalASTSource.h
@@ -51,6 +51,7 @@ class RecordDecl;
class Selector;
class Stmt;
class TagDecl;
+class VarDecl;
/// Abstract interface for external sources of AST nodes.
///
@@ -195,6 +196,10 @@ public:
/// module.
virtual bool wasThisDeclarationADefinition(const FunctionDecl *FD);
+ virtual bool hasInitializerWithSideEffects(const VarDecl *VD) const {
+ return false;
+ }
+
/// Finds all declarations lexically contained within the given
/// DeclContext, after applying an optional filter predicate.
///
@@ -429,6 +434,17 @@ public:
return GetPtr();
}
+ /// Retrieve the pointer to the AST node that this lazy pointer points to,
+ /// if it can be done without triggering deserialization.
+ ///
+ /// \returns a pointer to the AST node, or null if not yet deserialized.
+ T *getWithoutDeserializing() const {
+ if (isOffset()) {
+ return nullptr;
+ }
+ return GetPtr();
+ }
+
/// Retrieve the address of the AST node pointer. Deserializes the pointee if
/// necessary.
T **getAddressOfPointer(ExternalASTSource *Source) const {
diff --git a/clang/include/clang/Sema/MultiplexExternalSemaSource.h b/clang/include/clang/Sema/MultiplexExternalSemaSource.h
index 391c217..7c66c26 100644
--- a/clang/include/clang/Sema/MultiplexExternalSemaSource.h
+++ b/clang/include/clang/Sema/MultiplexExternalSemaSource.h
@@ -94,6 +94,8 @@ public:
bool wasThisDeclarationADefinition(const FunctionDecl *FD) override;
+ bool hasInitializerWithSideEffects(const VarDecl *VD) const override;
+
/// Find all declarations with the given name in the
/// given context.
bool FindExternalVisibleDeclsByName(const DeclContext *DC,
diff --git a/clang/include/clang/Serialization/ASTReader.h b/clang/include/clang/Serialization/ASTReader.h
index be1c6e0..7a4b7d2 100644
--- a/clang/include/clang/Serialization/ASTReader.h
+++ b/clang/include/clang/Serialization/ASTReader.h
@@ -1455,6 +1455,12 @@ private:
const StringRef &operator*() && = delete;
};
+ /// VarDecls with initializers containing side effects must be emitted,
+ /// but DeclMustBeEmitted is not allowed to deserialize the intializer.
+ /// FIXME: Lower memory usage by removing VarDecls once the initializer
+ /// is deserialized.
+ llvm::SmallPtrSet<Decl *, 16> InitSideEffectVars;
+
public:
/// Get the buffer for resolving paths.
SmallString<0> &getPathBuf() { return PathBuf; }
@@ -2406,6 +2412,8 @@ public:
bool wasThisDeclarationADefinition(const FunctionDecl *FD) override;
+ bool hasInitializerWithSideEffects(const VarDecl *VD) const override;
+
/// Retrieve a selector from the given module with its local ID
/// number.
Selector getLocalSelector(ModuleFile &M, unsigned LocalID);
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 02d6570..faad042 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -13111,9 +13111,7 @@ bool ASTContext::DeclMustBeEmitted(const Decl *D) {
return true;
// Variables that have initialization with side-effects are required.
- if (VD->getInit() && VD->getInit()->HasSideEffects(*this) &&
- // We can get a value-dependent initializer during error recovery.
- (VD->getInit()->isValueDependent() || !VD->evaluateValue()))
+ if (VD->hasInitWithSideEffects())
return true;
// Likewise, variables with tuple-like bindings are required if their
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 20a3db1..9e993f9 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -2441,6 +2441,30 @@ VarDecl *VarDecl::getInitializingDeclaration() {
return Def;
}
+bool VarDecl::hasInitWithSideEffects() const {
+ if (!hasInit())
+ return false;
+
+ // Check if we can get the initializer without deserializing
+ const Expr *E = nullptr;
+ if (auto *S = dyn_cast<Stmt *>(Init)) {
+ E = cast<Expr>(S);
+ } else {
+ E = cast_or_null<Expr>(getEvaluatedStmt()->Value.getWithoutDeserializing());
+ }
+
+ if (E)
+ return E->HasSideEffects(getASTContext()) &&
+ // We can get a value-dependent initializer during error recovery.
+ (E->isValueDependent() || !evaluateValue());
+
+ assert(getEvaluatedStmt()->Value.isOffset());
+ // ASTReader tracks this without having to deserialize the initializer
+ if (auto Source = getASTContext().getExternalSource())
+ return Source->hasInitializerWithSideEffects(this);
+ return false;
+}
+
bool VarDecl::isOutOfLine() const {
if (Decl::isOutOfLine())
return true;
diff --git a/clang/lib/Sema/MultiplexExternalSemaSource.cpp b/clang/lib/Sema/MultiplexExternalSemaSource.cpp
index fbfb242..9f19f13 100644
--- a/clang/lib/Sema/MultiplexExternalSemaSource.cpp
+++ b/clang/lib/Sema/MultiplexExternalSemaSource.cpp
@@ -115,6 +115,14 @@ bool MultiplexExternalSemaSource::wasThisDeclarationADefinition(
return false;
}
+bool MultiplexExternalSemaSource::hasInitializerWithSideEffects(
+ const VarDecl *VD) const {
+ for (const auto &S : Sources)
+ if (S->hasInitializerWithSideEffects(VD))
+ return true;
+ return false;
+}
+
bool MultiplexExternalSemaSource::FindExternalVisibleDeclsByName(
const DeclContext *DC, DeclarationName Name,
const DeclContext *OriginalDC) {
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index a3fbc3d..6f082fe 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -9722,6 +9722,10 @@ bool ASTReader::wasThisDeclarationADefinition(const FunctionDecl *FD) {
return ThisDeclarationWasADefinitionSet.contains(FD);
}
+bool ASTReader::hasInitializerWithSideEffects(const VarDecl *VD) const {
+ return InitSideEffectVars.count(VD);
+}
+
Selector ASTReader::getLocalSelector(ModuleFile &M, unsigned LocalID) {
return DecodeSelector(getGlobalSelectorID(M, LocalID));
}
diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 7f78826..0ffd784 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -1628,6 +1628,9 @@ RedeclarableResult ASTDeclReader::VisitVarDeclImpl(VarDecl *VD) {
VD->NonParmVarDeclBits.PreviousDeclInSameBlockScope =
VarDeclBits.getNextBit();
+ if (VarDeclBits.getNextBit())
+ Reader.InitSideEffectVars.insert(VD);
+
VD->NonParmVarDeclBits.EscapingByref = VarDeclBits.getNextBit();
HasDeducedType = VarDeclBits.getNextBit();
VD->NonParmVarDeclBits.ImplicitParamKind =
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index 2d93832..2e390db 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -1306,6 +1306,7 @@ void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
VarDeclBits.addBit(D->isConstexpr());
VarDeclBits.addBit(D->isInitCapture());
VarDeclBits.addBit(D->isPreviousDeclInSameBlockScope());
+ VarDeclBits.addBit(D->hasInitWithSideEffects());
VarDeclBits.addBit(D->isEscapingByref());
HasDeducedType = D->getType()->getContainedDeducedType();
@@ -1355,10 +1356,11 @@ void ASTDeclWriter::VisitVarDecl(VarDecl *D) {
!D->hasExtInfo() && D->getFirstDecl() == D->getMostRecentDecl() &&
D->getKind() == Decl::Var && !D->isInline() && !D->isConstexpr() &&
!D->isInitCapture() && !D->isPreviousDeclInSameBlockScope() &&
- !D->isEscapingByref() && !HasDeducedType &&
- D->getStorageDuration() != SD_Static && !D->getDescribedVarTemplate() &&
- !D->getMemberSpecializationInfo() && !D->isObjCForDecl() &&
- !isa<ImplicitParamDecl>(D) && !D->isEscapingByref())
+ !D->hasInitWithSideEffects() && !D->isEscapingByref() &&
+ !HasDeducedType && D->getStorageDuration() != SD_Static &&
+ !D->getDescribedVarTemplate() && !D->getMemberSpecializationInfo() &&
+ !D->isObjCForDecl() && !isa<ImplicitParamDecl>(D) &&
+ !D->isEscapingByref())
AbbrevToUse = Writer.getDeclVarAbbrev();
Code = serialization::DECL_VAR;
@@ -2731,12 +2733,12 @@ void ASTWriter::WriteDeclAbbrevs() {
// VarDecl
Abv->Add(BitCodeAbbrevOp(
BitCodeAbbrevOp::Fixed,
- 21)); // Packed Var Decl bits: Linkage, ModulesCodegen,
+ 22)); // Packed Var Decl bits: Linkage, ModulesCodegen,
// SClass, TSCSpec, InitStyle,
// isARCPseudoStrong, IsThisDeclarationADemotedDefinition,
// isExceptionVariable, isNRVOVariable, isCXXForRangeDecl,
// isInline, isInlineSpecified, isConstexpr,
- // isInitCapture, isPrevDeclInSameScope,
+ // isInitCapture, isPrevDeclInSameScope, hasInitWithSideEffects,
// EscapingByref, HasDeducedType, ImplicitParamKind, isObjCForDecl
Abv->Add(BitCodeAbbrevOp(0)); // VarKind (local enum)
// Type Source Info
diff --git a/clang/test/Modules/var-init-side-effects.cpp b/clang/test/Modules/var-init-side-effects.cpp
new file mode 100644
index 0000000..438a9eb
--- /dev/null
+++ b/clang/test/Modules/var-init-side-effects.cpp
@@ -0,0 +1,37 @@
+// Tests referencing variable with initializer containing side effect across module boundary
+//
+// RUN: rm -rf %t
+// RUN: mkdir -p %t
+// RUN: split-file %s %t
+
+// RUN: %clang_cc1 -std=c++20 -emit-module-interface %t/Foo.cppm \
+// RUN: -o %t/Foo.pcm
+
+// RUN: %clang_cc1 -std=c++20 -emit-module-interface \
+// RUN: -fmodule-file=Foo=%t/Foo.pcm \
+// RUN: %t/Bar.cppm \
+// RUN: -o %t/Bar.pcm
+
+// RUN: %clang_cc1 -std=c++20 -emit-obj \
+// RUN: -main-file-name Bar.cppm \
+// RUN: -fmodule-file=Foo=%t/Foo.pcm \
+// RUN: -x pcm %t/Bar.pcm \
+// RUN: -o %t/Bar.o
+
+//--- Foo.cppm
+export module Foo;
+
+export {
+class S {};
+
+inline S s = S{};
+}
+
+//--- Bar.cppm
+export module Bar;
+import Foo;
+
+S bar() {
+ return s;
+}
+
generated by cgit v1.1 at 2025-08-02 22:28:36 +0000