[clang] 2edb89c - Lex arguments for __has_cpp_attribute and friends as expanded tokens
Aaron Ballman via cfe-commits
cfe-commits at lists.llvm.org
Sun Oct 17 04:58:02 PDT 2021
Author: Aaron Ballman
Date: 2021-10-17T07:54:48-04:00
New Revision: 2edb89c746848c52964537268bf03e7906bf2542
URL: https://github.com/llvm/llvm-project/commit/2edb89c746848c52964537268bf03e7906bf2542
DIFF: https://github.com/llvm/llvm-project/commit/2edb89c746848c52964537268bf03e7906bf2542.diff
LOG: Lex arguments for __has_cpp_attribute and friends as expanded tokens
The C and C++ standards require the argument to __has_cpp_attribute and
__has_c_attribute to be expanded ([cpp.cond]p5). It would make little sense
to expand the argument to those operators but not expand the argument to
__has_attribute and __has_declspec, so those were both also changed in this
patch.
Note that it might make sense for the other builtins to also expand their
argument, but it wasn't as clear to me whether the behavior would be correct
there, and so they were left for a future revision.
Added:
clang/test/Preprocessor/has_attribute_errors.cpp
Modified:
clang/docs/ReleaseNotes.rst
clang/lib/Lex/PPMacroExpansion.cpp
clang/test/Preprocessor/has_attribute.c
clang/test/Preprocessor/has_attribute.cpp
clang/test/Preprocessor/has_c_attribute.c
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 6501a4870e2a6..263eae83036df 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -110,6 +110,13 @@ Attribute Changes in Clang
attribute is handled instead, e.g. in ``handleDeclAttribute``.
(This was changed in order to better support attributes in code completion).
+- __has_cpp_attribute, __has_c_attribute, __has_attribute, and __has_declspec
+ will now macro expand their argument. This causes a change in behavior for
+ code using ``__has_cpp_attribute(__clang__::attr)`` (and same for
+ ``__has_c_attribute``) where it would previously expand to ``0`` for all
+ attributes, but will now issue an error due to the expansion of the
+ predefined ``__clang__`` macro.
+
Windows Support
---------------
diff --git a/clang/lib/Lex/PPMacroExpansion.cpp b/clang/lib/Lex/PPMacroExpansion.cpp
index bf19f538647e6..5a0fa5184e38b 100644
--- a/clang/lib/Lex/PPMacroExpansion.cpp
+++ b/clang/lib/Lex/PPMacroExpansion.cpp
@@ -1293,7 +1293,7 @@ static bool EvaluateHasIncludeNext(Token &Tok,
/// integer values.
static void EvaluateFeatureLikeBuiltinMacro(llvm::raw_svector_ostream& OS,
Token &Tok, IdentifierInfo *II,
- Preprocessor &PP,
+ Preprocessor &PP, bool ExpandArgs,
llvm::function_ref<
int(Token &Tok,
bool &HasLexedNextTok)> Op) {
@@ -1319,7 +1319,10 @@ static void EvaluateFeatureLikeBuiltinMacro(llvm::raw_svector_ostream& OS,
bool SuppressDiagnostic = false;
while (true) {
// Parse next token.
- PP.LexUnexpandedToken(Tok);
+ if (ExpandArgs)
+ PP.Lex(Tok);
+ else
+ PP.LexUnexpandedToken(Tok);
already_lexed:
switch (Tok.getKind()) {
@@ -1609,21 +1612,21 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
OS << CounterValue++;
Tok.setKind(tok::numeric_constant);
} else if (II == Ident__has_feature) {
- EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this,
+ EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this, false,
[this](Token &Tok, bool &HasLexedNextToken) -> int {
IdentifierInfo *II = ExpectFeatureIdentifierInfo(Tok, *this,
diag::err_feature_check_malformed);
return II && HasFeature(*this, II->getName());
});
} else if (II == Ident__has_extension) {
- EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this,
+ EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this, false,
[this](Token &Tok, bool &HasLexedNextToken) -> int {
IdentifierInfo *II = ExpectFeatureIdentifierInfo(Tok, *this,
diag::err_feature_check_malformed);
return II && HasExtension(*this, II->getName());
});
} else if (II == Ident__has_builtin) {
- EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this,
+ EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this, false,
[this](Token &Tok, bool &HasLexedNextToken) -> int {
IdentifierInfo *II = ExpectFeatureIdentifierInfo(Tok, *this,
diag::err_feature_check_malformed);
@@ -1675,12 +1678,12 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
}
});
} else if (II == Ident__is_identifier) {
- EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this,
+ EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this, false,
[](Token &Tok, bool &HasLexedNextToken) -> int {
return Tok.is(tok::identifier);
});
} else if (II == Ident__has_attribute) {
- EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this,
+ EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this, true,
[this](Token &Tok, bool &HasLexedNextToken) -> int {
IdentifierInfo *II = ExpectFeatureIdentifierInfo(Tok, *this,
diag::err_feature_check_malformed);
@@ -1688,7 +1691,7 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
getTargetInfo(), getLangOpts()) : 0;
});
} else if (II == Ident__has_declspec) {
- EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this,
+ EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this, true,
[this](Token &Tok, bool &HasLexedNextToken) -> int {
IdentifierInfo *II = ExpectFeatureIdentifierInfo(Tok, *this,
diag::err_feature_check_malformed);
@@ -1704,8 +1707,8 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
} else if (II == Ident__has_cpp_attribute ||
II == Ident__has_c_attribute) {
bool IsCXX = II == Ident__has_cpp_attribute;
- EvaluateFeatureLikeBuiltinMacro(
- OS, Tok, II, *this, [&](Token &Tok, bool &HasLexedNextToken) -> int {
+ EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this, true,
+ [&](Token &Tok, bool &HasLexedNextToken) -> int {
IdentifierInfo *ScopeII = nullptr;
IdentifierInfo *II = ExpectFeatureIdentifierInfo(
Tok, *this, diag::err_feature_check_malformed);
@@ -1719,7 +1722,8 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
HasLexedNextToken = true;
else {
ScopeII = II;
- LexUnexpandedToken(Tok);
+ // Lex an expanded token for the attribute name.
+ Lex(Tok);
II = ExpectFeatureIdentifierInfo(Tok, *this,
diag::err_feature_check_malformed);
}
@@ -1746,7 +1750,7 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
Tok.setKind(tok::numeric_constant);
} else if (II == Ident__has_warning) {
// The argument should be a parenthesized string literal.
- EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this,
+ EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this, false,
[this](Token &Tok, bool &HasLexedNextToken) -> int {
std::string WarningName;
SourceLocation StrStartLoc = Tok.getLocation();
@@ -1777,7 +1781,7 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
// The argument to this builtin should be an identifier. The
// builtin evaluates to 1 when that identifier names the module we are
// currently building.
- EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this,
+ EvaluateFeatureLikeBuiltinMacro(OS, Tok, II, *this, false,
[this](Token &Tok, bool &HasLexedNextToken) -> int {
IdentifierInfo *II = ExpectFeatureIdentifierInfo(Tok, *this,
diag::err_expected_id_building_module);
@@ -1837,28 +1841,32 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
return;
} else if (II == Ident__is_target_arch) {
EvaluateFeatureLikeBuiltinMacro(
- OS, Tok, II, *this, [this](Token &Tok, bool &HasLexedNextToken) -> int {
+ OS, Tok, II, *this, false,
+ [this](Token &Tok, bool &HasLexedNextToken) -> int {
IdentifierInfo *II = ExpectFeatureIdentifierInfo(
Tok, *this, diag::err_feature_check_malformed);
return II && isTargetArch(getTargetInfo(), II);
});
} else if (II == Ident__is_target_vendor) {
EvaluateFeatureLikeBuiltinMacro(
- OS, Tok, II, *this, [this](Token &Tok, bool &HasLexedNextToken) -> int {
+ OS, Tok, II, *this, false,
+ [this](Token &Tok, bool &HasLexedNextToken) -> int {
IdentifierInfo *II = ExpectFeatureIdentifierInfo(
Tok, *this, diag::err_feature_check_malformed);
return II && isTargetVendor(getTargetInfo(), II);
});
} else if (II == Ident__is_target_os) {
EvaluateFeatureLikeBuiltinMacro(
- OS, Tok, II, *this, [this](Token &Tok, bool &HasLexedNextToken) -> int {
+ OS, Tok, II, *this, false,
+ [this](Token &Tok, bool &HasLexedNextToken) -> int {
IdentifierInfo *II = ExpectFeatureIdentifierInfo(
Tok, *this, diag::err_feature_check_malformed);
return II && isTargetOS(getTargetInfo(), II);
});
} else if (II == Ident__is_target_environment) {
EvaluateFeatureLikeBuiltinMacro(
- OS, Tok, II, *this, [this](Token &Tok, bool &HasLexedNextToken) -> int {
+ OS, Tok, II, *this, false,
+ [this](Token &Tok, bool &HasLexedNextToken) -> int {
IdentifierInfo *II = ExpectFeatureIdentifierInfo(
Tok, *this, diag::err_feature_check_malformed);
return II && isTargetEnvironment(getTargetInfo(), II);
diff --git a/clang/test/Preprocessor/has_attribute.c b/clang/test/Preprocessor/has_attribute.c
index 4970dc5904230..eef168e879103 100644
--- a/clang/test/Preprocessor/has_attribute.c
+++ b/clang/test/Preprocessor/has_attribute.c
@@ -56,3 +56,11 @@ int has_no_volatile_attribute();
#if __has_cpp_attribute(selectany) // expected-error {{function-like macro '__has_cpp_attribute' is not defined}}
#endif
+
+// Test that macro expansion of the builtin argument works.
+#define F fallthrough
+
+#if __has_attribute(F)
+int has_fallthrough;
+#endif
+// CHECK: int has_fallthrough;
diff --git a/clang/test/Preprocessor/has_attribute.cpp b/clang/test/Preprocessor/has_attribute.cpp
index fe7d29f15de1a..bf0f9b3bc4a8f 100644
--- a/clang/test/Preprocessor/has_attribute.cpp
+++ b/clang/test/Preprocessor/has_attribute.cpp
@@ -18,16 +18,6 @@ CXX11(clang::__fallthrough__)
// CHECK: __gsl__::suppress: 0
CXX11(__gsl__::suppress)
-// We do somewhat support the __clang__ vendor namespace, but it is a
-// predefined macro and thus we encourage users to use _Clang instead.
-// Because of this, we do not support __has_cpp_attribute for that
-// vendor namespace.
-//
-// Note, we can't use CXX11 here because it will expand __clang__ to 1
-// too early.
-// CHECK: 1::fallthrough: 0
-__clang__::fallthrough: __has_cpp_attribute(__clang__::fallthrough)
-
// CHECK: _Clang::fallthrough: 201603L
CXX11(_Clang::fallthrough)
@@ -70,6 +60,50 @@ CXX11(unlikely)
// CHECK: noreturn: 200809L
// CHECK: unlikely: 201803L
+namespace PR48462 {
+// Test that macro expansion of the builtin argument works.
+#define C clang
+#define F fallthrough
+#define CF clang::fallthrough
+
+#if __has_cpp_attribute(F)
+int has_fallthrough;
+#endif
+// CHECK: int has_fallthrough;
+
+#if __has_cpp_attribute(C::F)
+int has_clang_falthrough_1;
+#endif
+// CHECK: int has_clang_falthrough_1;
+
+#if __has_cpp_attribute(clang::F)
+int has_clang_falthrough_2;
+#endif
+// CHECK: int has_clang_falthrough_2;
+
+#if __has_cpp_attribute(C::fallthrough)
+int has_clang_falthrough_3;
+#endif
+// CHECK: int has_clang_falthrough_3;
+
+#if __has_cpp_attribute(CF)
+int has_clang_falthrough_4;
+#endif
+// CHECK: int has_clang_falthrough_4;
+
+#define FUNCLIKE1(x) clang::x
+#if __has_cpp_attribute(FUNCLIKE1(fallthrough))
+int funclike_1;
+#endif
+// CHECK: int funclike_1;
+
+#define FUNCLIKE2(x) _Clang::x
+#if __has_cpp_attribute(FUNCLIKE2(fallthrough))
+int funclike_2;
+#endif
+// CHECK: int funclike_2;
+}
+
// Test for Microsoft __declspec attributes
#define DECLSPEC(x) x: __has_declspec_attribute(x)
@@ -81,3 +115,13 @@ DECLSPEC(__uuid__)
// CHECK: fallthrough: 0
DECLSPEC(fallthrough)
+
+namespace PR48462 {
+// Test that macro expansion of the builtin argument works.
+#define U uuid
+
+#if __has_declspec_attribute(U)
+int has_uuid;
+#endif
+// CHECK: int has_uuid;
+}
diff --git a/clang/test/Preprocessor/has_attribute_errors.cpp b/clang/test/Preprocessor/has_attribute_errors.cpp
new file mode 100644
index 0000000000000..1fc88d3f926fb
--- /dev/null
+++ b/clang/test/Preprocessor/has_attribute_errors.cpp
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -triple i386-unknown-unknown -Eonly -verify %s
+
+// We warn users if they write an attribute like
+// [[__clang__::fallthrough]] because __clang__ is a macro that expands to 1.
+// Instead, we suggest users use [[_Clang::fallthrough]] in this situation.
+// However, because __has_cpp_attribute (and __has_c_attribute) require
+// expanding their argument tokens, __clang__ expands to 1 in the feature test
+// macro as well. We don't currently give users a kind warning in this case,
+// but we previously did not expand macros and so this would return 0. Now that
+// we properly expand macros, users will now get an error about using incorrect
+// syntax.
+
+__has_cpp_attribute(__clang__::fallthrough) // expected-error {{missing ')' after <numeric_constant>}} \
+ // expected-note {{to match this '('}} \
+ // expected-error {{builtin feature check macro requires a parenthesized identifier}}
+
diff --git a/clang/test/Preprocessor/has_c_attribute.c b/clang/test/Preprocessor/has_c_attribute.c
index 670e42a97926e..36dd1c80e7802 100644
--- a/clang/test/Preprocessor/has_c_attribute.c
+++ b/clang/test/Preprocessor/has_c_attribute.c
@@ -33,12 +33,45 @@ C2x(__gnu__::warn_unused_result)
// CHECK: gnu::__warn_unused_result__: 201904L
C2x(gnu::__warn_unused_result__)
-// We do somewhat support the __clang__ vendor namespace, but it is a
-// predefined macro and thus we encourage users to use _Clang instead.
-// Because of this, we do not support __has_c_attribute for that
-// vendor namespace.
-//
-// Note, we can't use C2x here because it will expand __clang__ to 1
-// too early.
-// CHECK: 1::fallthrough: 0
-__clang__::fallthrough: __has_c_attribute(__clang__::fallthrough)
+// Test that macro expansion of the builtin argument works.
+#define C clang
+#define L likely
+#define CL clang::likely
+#define N nodiscard
+
+#if __has_c_attribute(N)
+int has_nodiscard;
+#endif
+// CHECK: int has_nodiscard;
+
+#if __has_c_attribute(C::L)
+int has_clang_likely_1;
+#endif
+// CHECK: int has_clang_likely_1;
+
+#if __has_c_attribute(clang::L)
+int has_clang_likely_2;
+#endif
+// CHECK: int has_clang_likely_2;
+
+#if __has_c_attribute(C::likely)
+int has_clang_likely_3;
+#endif
+// CHECK: int has_clang_likely_3;
+
+#if __has_c_attribute(CL)
+int has_clang_likely_4;
+#endif
+// CHECK: int has_clang_likely_4;
+
+#define FUNCLIKE1(x) clang::x
+#if __has_c_attribute(FUNCLIKE1(likely))
+int funclike_1;
+#endif
+// CHECK: int funclike_1;
+
+#define FUNCLIKE2(x) _Clang::x
+#if __has_c_attribute(FUNCLIKE2(likely))
+int funclike_2;
+#endif
+// CHECK: int funclike_2;
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