[Modules] Fix an identifier hiding a function-like macro definition. (#135471)
We emit a macro definition only in a module defining it. But it means
that if another module has an identifier with the same name as the
macro, the users of such module won't be able to use the macro anymore.
Fix by storing that an identifier has a macro definition that's not in a
current module (`MacroDirectivesOffset == 0`). This way
`IdentifierLookupVisitor` knows not to stop at the first module with an
identifier but to keep checking included modules for the actual macro
definition.
Fixes issue #32040.
rdar://30258278
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 02c31df..58d3d33 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -1131,7 +1131,7 @@
bool HasRevertedTokenIDToIdentifier = readBit(Bits);
bool Poisoned = readBit(Bits);
bool ExtensionToken = readBit(Bits);
- bool HadMacroDefinition = readBit(Bits);
+ bool HasMacroDefinition = readBit(Bits);
assert(Bits == 0 && "Extra bits in the identifier?");
DataLen -= sizeof(uint16_t) * 2;
@@ -1151,14 +1151,17 @@
"Incorrect C++ operator keyword flag");
(void)CPlusPlusOperatorKeyword;
- // If this identifier is a macro, deserialize the macro
- // definition.
- if (HadMacroDefinition) {
+ // If this identifier has a macro definition, deserialize it or notify the
+ // visitor the actual definition is in a different module.
+ if (HasMacroDefinition) {
uint32_t MacroDirectivesOffset =
endian::readNext<uint32_t, llvm::endianness::little>(d);
DataLen -= 4;
- Reader.addPendingMacro(II, &F, MacroDirectivesOffset);
+ if (MacroDirectivesOffset)
+ Reader.addPendingMacro(II, &F, MacroDirectivesOffset);
+ else
+ hasMacroDefinitionInDependencies = true;
}
Reader.SetIdentifierInfo(ID, II);
@@ -2419,6 +2422,10 @@
// declarations it needs.
++NumIdentifierLookupHits;
Found = *Pos;
+ if (Trait.hasMoreInformationInDependencies()) {
+ // Look for the identifier in extra modules as they contain more info.
+ return false;
+ }
return true;
}
diff --git a/clang/lib/Serialization/ASTReaderInternals.h b/clang/lib/Serialization/ASTReaderInternals.h
index 353e0a5..4a77948 100644
--- a/clang/lib/Serialization/ASTReaderInternals.h
+++ b/clang/lib/Serialization/ASTReaderInternals.h
@@ -286,6 +286,8 @@
// identifier that was constructed before the AST file was read.
IdentifierInfo *KnownII;
+ bool hasMacroDefinitionInDependencies = false;
+
public:
using data_type = IdentifierInfo *;
@@ -300,6 +302,10 @@
IdentifierID ReadIdentifierID(const unsigned char *d);
ASTReader &getReader() const { return Reader; }
+
+ bool hasMoreInformationInDependencies() const {
+ return hasMacroDefinitionInDependencies;
+ }
};
/// The on-disk hash table used to contain information about
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 95b5718..8c261e1 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -3795,7 +3795,10 @@
II->getNotableIdentifierID() != tok::NotableIdentifierKind::not_notable ||
II->getBuiltinID() != Builtin::ID::NotBuiltin ||
II->getObjCKeywordID() != tok::ObjCKeywordKind::objc_not_keyword;
- if (MacroOffset || II->isPoisoned() || (!IsModule && IsInteresting) ||
+ if (MacroOffset ||
+ (II->hasMacroDefinition() &&
+ II->hasFETokenInfoChangedSinceDeserialization()) ||
+ II->isPoisoned() || (!IsModule && IsInteresting) ||
II->hasRevertedTokenIDToIdentifier() ||
(NeedDecls && II->getFETokenInfo()))
return true;
@@ -3874,7 +3877,8 @@
if (isInterestingIdentifier(II, MacroOffset)) {
DataLen += 2; // 2 bytes for builtin ID
DataLen += 2; // 2 bytes for flags
- if (MacroOffset)
+ if (MacroOffset || (II->hasMacroDefinition() &&
+ II->hasFETokenInfoChangedSinceDeserialization()))
DataLen += 4; // MacroDirectives offset.
if (NeedDecls && IdResolver)
@@ -3905,15 +3909,17 @@
assert((Bits & 0xffff) == Bits && "ObjCOrBuiltinID too big for ASTReader.");
LE.write<uint16_t>(Bits);
Bits = 0;
- bool HadMacroDefinition = MacroOffset != 0;
- Bits = (Bits << 1) | unsigned(HadMacroDefinition);
+ bool HasMacroDefinition =
+ (MacroOffset != 0) || (II->hasMacroDefinition() &&
+ II->hasFETokenInfoChangedSinceDeserialization());
+ Bits = (Bits << 1) | unsigned(HasMacroDefinition);
Bits = (Bits << 1) | unsigned(II->isExtensionToken());
Bits = (Bits << 1) | unsigned(II->isPoisoned());
Bits = (Bits << 1) | unsigned(II->hasRevertedTokenIDToIdentifier());
Bits = (Bits << 1) | unsigned(II->isCPlusPlusOperatorKeyword());
LE.write<uint16_t>(Bits);
- if (HadMacroDefinition)
+ if (HasMacroDefinition)
LE.write<uint32_t>(MacroOffset);
if (NeedDecls && IdResolver) {
diff --git a/clang/test/Modules/macro-identifier-hiding.c b/clang/test/Modules/macro-identifier-hiding.c
new file mode 100644
index 0000000..4cd7cf0
--- /dev/null
+++ b/clang/test/Modules/macro-identifier-hiding.c
@@ -0,0 +1,29 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: %clang_cc1 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t/modules.cache \
+// RUN: -fsyntax-only %t/test.c -verify
+// Test again with the populated module cache.
+// RUN: %clang_cc1 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t/modules.cache \
+// RUN: -fsyntax-only %t/test.c -verify
+
+// Test that an identifier with the same name as a macro doesn't hide this
+// macro from the includers.
+
+//--- macro-definition.h
+#define __P(protos) ()
+#define __Q(protos) ()
+
+//--- macro-transitive.h
+#include "macro-definition.h"
+void test(int __P) {} // not "interesting" identifier
+struct __Q {}; // "interesting" identifier
+
+//--- module.modulemap
+module MacroDefinition { header "macro-definition.h" export * }
+module MacroTransitive { header "macro-transitive.h" export * }
+
+//--- test.c
+// expected-no-diagnostics
+#include "macro-transitive.h"
+void foo __P(());
+void bar __Q(());
