[clang] c22625c - [C2y] Remove support for _Imaginary (#97436)
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cfe-commits at lists.llvm.org
Mon Jul 8 10:43:07 PDT 2024
Author: Aaron Ballman
Date: 2024-07-08T13:43:03-04:00
New Revision: c22625cb3eaf052e2377881d64640196ff5da3d1
URL: https://github.com/llvm/llvm-project/commit/c22625cb3eaf052e2377881d64640196ff5da3d1
DIFF: https://github.com/llvm/llvm-project/commit/c22625cb3eaf052e2377881d64640196ff5da3d1.diff
LOG: [C2y] Remove support for _Imaginary (#97436)
WG14 N3274 removed _Imaginary from Annex G. Clang has never fully
supported Annex G or _Imaginary, so removal is pretty trivial for us.
Note, we are keeping _Imaginary as a keyword so that we get better
diagnostic behavior. This is still conforming because _I makes it a
reserved identifier, so it's not available for users to use as an
identifier anyway.
Added:
clang/test/C/C2y/n3274.c
Modified:
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/include/clang/Basic/TokenKinds.def
clang/include/clang/Sema/DeclSpec.h
clang/lib/CodeGen/CGExprComplex.cpp
clang/lib/Sema/DeclSpec.cpp
clang/lib/Sema/SemaCodeComplete.cpp
clang/lib/Sema/SemaLookup.cpp
clang/lib/Sema/SemaType.cpp
clang/www/c_status.html
Removed:
################################################################################
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 44fd51ec9abc96..1aba8bc24ba2fa 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -7696,7 +7696,6 @@ def err_qualified_objc_access : Error<
def ext_freestanding_complex : Extension<
"complex numbers are an extension in a freestanding C99 implementation">;
-// FIXME: Remove when we support imaginary.
def err_imaginary_not_supported : Error<"imaginary types are not supported">;
// Obj-c expressions
diff --git a/clang/include/clang/Basic/TokenKinds.def b/clang/include/clang/Basic/TokenKinds.def
index 37d570ca5e75b5..e6054425909098 100644
--- a/clang/include/clang/Basic/TokenKinds.def
+++ b/clang/include/clang/Basic/TokenKinds.def
@@ -331,6 +331,11 @@ KEYWORD(_Atomic , KEYALL|KEYNOOPENCL)
KEYWORD(_Bool , KEYNOCXX)
KEYWORD(_Complex , KEYALL)
KEYWORD(_Generic , KEYALL)
+// Note, C2y removed support for _Imaginary; we retain it as a keyword because
+// 1) it's a reserved identifier, so we're allowed to steal it, 2) there's no
+// good way to specify a keyword in earlier but not later language modes within
+// this file, 3) this allows us to provide a better diagnostic in case a user
+// does use the keyword.
KEYWORD(_Imaginary , KEYALL)
KEYWORD(_Noreturn , KEYALL)
KEYWORD(_Static_assert , KEYALL)
diff --git a/clang/include/clang/Sema/DeclSpec.h b/clang/include/clang/Sema/DeclSpec.h
index 23bc780e04979d..425b6e2a0b30c9 100644
--- a/clang/include/clang/Sema/DeclSpec.h
+++ b/clang/include/clang/Sema/DeclSpec.h
@@ -269,7 +269,7 @@ class DeclSpec {
enum TSC {
TSC_unspecified,
- TSC_imaginary,
+ TSC_imaginary, // Unsupported
TSC_complex
};
@@ -875,7 +875,7 @@ class DeclSpec {
}
/// Finish - This does final analysis of the declspec, issuing diagnostics for
- /// things like "_Imaginary" (lacking an FP type). After calling this method,
+ /// things like "_Complex" (lacking an FP type). After calling this method,
/// DeclSpec is guaranteed self-consistent, even if an error occurred.
void Finish(Sema &S, const PrintingPolicy &Policy);
diff --git a/clang/lib/CodeGen/CGExprComplex.cpp b/clang/lib/CodeGen/CGExprComplex.cpp
index 84ad3b566b6472..000d4ff5c06986 100644
--- a/clang/lib/CodeGen/CGExprComplex.cpp
+++ b/clang/lib/CodeGen/CGExprComplex.cpp
@@ -817,8 +817,6 @@ ComplexPairTy ComplexExprEmitter::EmitBinMul(const BinOpInfo &Op) {
//
// But we can fold away components which would be zero due to a real
// operand according to C11 Annex G.5.1p2.
- // FIXME: C11 also provides for imaginary types which would allow folding
- // still more of this within the type system.
CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, Op.FPFeatures);
if (Op.LHS.second && Op.RHS.second) {
@@ -1049,9 +1047,6 @@ ComplexPairTy ComplexExprEmitter::EmitBinDiv(const BinOpInfo &Op) {
// delegate to a libcall to handle all of the complexities and minimize
// underflow/overflow cases. When FastMath is allowed we construct the
// divide inline using the same algorithm as for integer operands.
- //
- // FIXME: We would be able to avoid the libcall in many places if we
- // supported imaginary types in addition to complex types.
BinOpInfo LibCallOp = Op;
// If LHS was a real, supply a null imaginary part.
if (!LHSi)
diff --git a/clang/lib/Sema/DeclSpec.cpp b/clang/lib/Sema/DeclSpec.cpp
index 96c90a60b96825..9a4d52d4b6b716 100644
--- a/clang/lib/Sema/DeclSpec.cpp
+++ b/clang/lib/Sema/DeclSpec.cpp
@@ -1146,7 +1146,7 @@ void DeclSpec::SaveWrittenBuiltinSpecs() {
}
/// Finish - This does final analysis of the declspec, rejecting things like
-/// "_Imaginary" (lacking an FP type). After calling this method, DeclSpec is
+/// "_Complex" (lacking an FP type). After calling this method, DeclSpec is
/// guaranteed to be self-consistent, even if an error occurred.
void DeclSpec::Finish(Sema &S, const PrintingPolicy &Policy) {
// Before possibly changing their values, save specs as written.
@@ -1331,8 +1331,8 @@ void DeclSpec::Finish(Sema &S, const PrintingPolicy &Policy) {
break;
}
- // TODO: if the implementation does not implement _Complex or _Imaginary,
- // disallow their use. Need information about the backend.
+ // TODO: if the implementation does not implement _Complex, disallow their
+ // use. Need information about the backend.
if (TypeSpecComplex != TSC_unspecified) {
if (TypeSpecType == TST_unspecified) {
S.Diag(TSCLoc, diag::ext_plain_complex)
diff --git a/clang/lib/Sema/SemaCodeComplete.cpp b/clang/lib/Sema/SemaCodeComplete.cpp
index 7ea760ce579386..8fea7b0cf0d47c 100644
--- a/clang/lib/Sema/SemaCodeComplete.cpp
+++ b/clang/lib/Sema/SemaCodeComplete.cpp
@@ -1805,7 +1805,8 @@ static void AddTypeSpecifierResults(const LangOptions &LangOpts,
if (LangOpts.C99) {
// C99-specific
Results.AddResult(Result("_Complex", CCP_Type));
- Results.AddResult(Result("_Imaginary", CCP_Type));
+ if (!LangOpts.C2y)
+ Results.AddResult(Result("_Imaginary", CCP_Type));
Results.AddResult(Result("_Bool", CCP_Type));
Results.AddResult(Result("restrict", CCP_Type));
}
diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index a4acf3b4fbf417..7851c5d080cf38 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -4983,7 +4983,7 @@ static void AddKeywordsToConsumer(Sema &SemaRef,
static const char *const CTypeSpecs[] = {
"char", "const", "double", "enum", "float", "int", "long", "short",
"signed", "struct", "union", "unsigned", "void", "volatile",
- "_Complex", "_Imaginary",
+ "_Complex",
// storage-specifiers as well
"extern", "inline", "static", "typedef"
};
@@ -4991,6 +4991,9 @@ static void AddKeywordsToConsumer(Sema &SemaRef,
for (const auto *CTS : CTypeSpecs)
Consumer.addKeywordResult(CTS);
+ if (SemaRef.getLangOpts().C99 && !SemaRef.getLangOpts().C2y)
+ Consumer.addKeywordResult("_Imaginary");
+
if (SemaRef.getLangOpts().C99)
Consumer.addKeywordResult("restrict");
if (SemaRef.getLangOpts().Bool || SemaRef.getLangOpts().CPlusPlus)
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 066003c47eb43f..f3510a00919940 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -1423,7 +1423,9 @@ static QualType ConvertDeclSpecToType(TypeProcessingState &state) {
Result = Context.getVectorType(Result, 128/typeSize, VecKind);
}
- // FIXME: Imaginary.
+ // _Imaginary was a feature of C99 through C23 but was never supported in
+ // Clang. The feature was removed in C2y, but we retain the unsupported
+ // diagnostic for an improved user experience.
if (DS.getTypeSpecComplex() == DeclSpec::TSC_imaginary)
S.Diag(DS.getTypeSpecComplexLoc(), diag::err_imaginary_not_supported);
diff --git a/clang/test/C/C2y/n3274.c b/clang/test/C/C2y/n3274.c
new file mode 100644
index 00000000000000..ccdb89f4069ded
--- /dev/null
+++ b/clang/test/C/C2y/n3274.c
@@ -0,0 +1,18 @@
+// RUN: %clang_cc1 -verify -std=c23 -Wall -pedantic %s
+// RUN: %clang_cc1 -verify -std=c2y -Wall -pedantic %s
+
+/* WG14 N3274: Yes
+ * Remove imaginary types
+ */
+
+// Clang has never supported _Imaginary.
+#ifdef __STDC_IEC_559_COMPLEX__
+#error "When did this happen?"
+#endif
+
+_Imaginary float i; // expected-error {{imaginary types are not supported}}
+
+// _Imaginary is a keyword in older language modes, but doesn't need to be one
+// in C2y or later. However, to improve diagnostic behavior, we retain it as a
+// keyword in all language modes -- it is not available as an identifier.
+static_assert(!__is_identifier(_Imaginary));
diff --git a/clang/www/c_status.html b/clang/www/c_status.html
index 2030e1e62a3f46..890ac1cd922863 100644
--- a/clang/www/c_status.html
+++ b/clang/www/c_status.html
@@ -1292,7 +1292,7 @@ <h2 id="c2y">C2y implementation status</h2>
<tr>
<td>Remove imaginary types</td>
<td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3274.pdf">N3274</a></td>
- <td class="unknown" align="center">Unknown</td>
+ <td class="full" align="center">Yes</td>
</tr>
</table>
</details>
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