r292555 - P0426: Make the library implementation of constexpr char_traits a little easier
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Thu Jan 19 16:45:36 PST 2017
Author: rsmith
Date: Thu Jan 19 18:45:35 2017
New Revision: 292555
URL: http://llvm.org/viewvc/llvm-project?rev=292555&view=rev
Log:
P0426: Make the library implementation of constexpr char_traits a little easier
by providing a memchr builtin that returns char* instead of void*.
Also add a __has_feature flag to indicate the presence of constexpr forms of
the relevant <string> functions.
Modified:
cfe/trunk/include/clang/Basic/Builtins.def
cfe/trunk/lib/AST/ExprConstant.cpp
cfe/trunk/lib/CodeGen/CGBuiltin.cpp
cfe/trunk/lib/Lex/PPMacroExpansion.cpp
cfe/trunk/test/CodeGenCXX/builtins.cpp
cfe/trunk/test/Lexer/has_feature_cxx0x.cpp
cfe/trunk/test/SemaCXX/constexpr-string.cpp
Modified: cfe/trunk/include/clang/Basic/Builtins.def
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/Builtins.def?rev=292555&r1=292554&r2=292555&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/Builtins.def (original)
+++ cfe/trunk/include/clang/Basic/Builtins.def Thu Jan 19 18:45:35 2017
@@ -1339,6 +1339,7 @@ BUILTIN(__builtin_smulll_overflow, "bSLL
BUILTIN(__builtin_addressof, "v*v&", "nct")
BUILTIN(__builtin_operator_new, "v*z", "c")
BUILTIN(__builtin_operator_delete, "vv*", "n")
+BUILTIN(__builtin_char_memchr, "c*cC*iz", "n")
// Safestack builtins
BUILTIN(__builtin___get_unsafe_stack_start, "v*", "Fn")
Modified: cfe/trunk/lib/AST/ExprConstant.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=292555&r1=292554&r2=292555&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprConstant.cpp (original)
+++ cfe/trunk/lib/AST/ExprConstant.cpp Thu Jan 19 18:45:35 2017
@@ -5683,6 +5683,7 @@ bool PointerExprEvaluator::VisitBuiltinC
case Builtin::BI__builtin_strchr:
case Builtin::BI__builtin_wcschr:
case Builtin::BI__builtin_memchr:
+ case Builtin::BI__builtin_char_memchr:
case Builtin::BI__builtin_wmemchr: {
if (!Visit(E->getArg(0)))
return false;
@@ -5720,6 +5721,7 @@ bool PointerExprEvaluator::VisitBuiltinC
// Fall through.
case Builtin::BImemchr:
case Builtin::BI__builtin_memchr:
+ case Builtin::BI__builtin_char_memchr:
// memchr compares by converting both sides to unsigned char. That's also
// correct for strchr if we get this far (to cope with plain char being
// unsigned in the strchr case).
Modified: cfe/trunk/lib/CodeGen/CGBuiltin.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGBuiltin.cpp?rev=292555&r1=292554&r2=292555&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGBuiltin.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGBuiltin.cpp Thu Jan 19 18:45:35 2017
@@ -1189,6 +1189,10 @@ RValue CodeGenFunction::EmitBuiltinExpr(
return RValue::get(Dest.getPointer());
}
+ case Builtin::BI__builtin_char_memchr:
+ BuiltinID = Builtin::BI__builtin_memchr;
+ break;
+
case Builtin::BI__builtin___memcpy_chk: {
// fold __builtin_memcpy_chk(x, y, cst1, cst2) to memcpy iff cst1<=cst2.
llvm::APSInt Size, DstSize;
Modified: cfe/trunk/lib/Lex/PPMacroExpansion.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Lex/PPMacroExpansion.cpp?rev=292555&r1=292554&r2=292555&view=diff
==============================================================================
--- cfe/trunk/lib/Lex/PPMacroExpansion.cpp (original)
+++ cfe/trunk/lib/Lex/PPMacroExpansion.cpp Thu Jan 19 18:45:35 2017
@@ -1183,6 +1183,7 @@ static bool HasFeature(const Preprocesso
.Case("cxx_attributes", LangOpts.CPlusPlus11)
.Case("cxx_auto_type", LangOpts.CPlusPlus11)
.Case("cxx_constexpr", LangOpts.CPlusPlus11)
+ .Case("cxx_constexpr_string_builtins", LangOpts.CPlusPlus11)
.Case("cxx_decltype", LangOpts.CPlusPlus11)
.Case("cxx_decltype_incomplete_return_types", LangOpts.CPlusPlus11)
.Case("cxx_default_function_template_args", LangOpts.CPlusPlus11)
Modified: cfe/trunk/test/CodeGenCXX/builtins.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/builtins.cpp?rev=292555&r1=292554&r2=292555&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/builtins.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/builtins.cpp Thu Jan 19 18:45:35 2017
@@ -26,3 +26,7 @@ int x = __builtin_abs(-2);
long y = __builtin_abs(-2l);
// CHECK: [[Y:%.+]] = call i64 @_Z13__builtin_absl(i64 -2)
// CHECK: store i64 [[Y]], i64* @y, align 8
+
+extern const char char_memchr_arg[32];
+char *memchr_result = __builtin_char_memchr(char_memchr_arg, 123, 32);
+// CHECK: call i8* @memchr(i8* getelementptr inbounds ([32 x i8], [32 x i8]* @char_memchr_arg, i32 0, i32 0), i32 123, i64 32)
Modified: cfe/trunk/test/Lexer/has_feature_cxx0x.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Lexer/has_feature_cxx0x.cpp?rev=292555&r1=292554&r2=292555&view=diff
==============================================================================
--- cfe/trunk/test/Lexer/has_feature_cxx0x.cpp (original)
+++ cfe/trunk/test/Lexer/has_feature_cxx0x.cpp Thu Jan 19 18:45:35 2017
@@ -301,6 +301,17 @@ int no_constexpr();
// CHECK-11: has_constexpr
// CHECK-NO-11: no_constexpr
+#if __has_feature(cxx_constexpr_string_builtins)
+int has_constexpr_string_builtins();
+#else
+int no_constexpr_string_builtins();
+#endif
+
+// CHECK-1Z: has_constexpr_string_builtins
+// CHECK-14: has_constexpr_string_builtins
+// CHECK-11: has_constexpr_string_builtins
+// CHECK-NO-11: no_constexpr_string_builtins
+
#if __has_feature(cxx_generalized_initializers)
int has_generalized_initializers();
#else
Modified: cfe/trunk/test/SemaCXX/constexpr-string.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/constexpr-string.cpp?rev=292555&r1=292554&r2=292555&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/constexpr-string.cpp (original)
+++ cfe/trunk/test/SemaCXX/constexpr-string.cpp Thu Jan 19 18:45:35 2017
@@ -166,6 +166,27 @@ namespace StrchrEtc {
static_assert(__builtin_memchr(nullptr, 'x', 3) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
static_assert(__builtin_memchr(nullptr, 'x', 0) == nullptr); // FIXME: Should we reject this?
+ static_assert(__builtin_char_memchr(kStr, 'a', 0) == nullptr);
+ static_assert(__builtin_char_memchr(kStr, 'a', 1) == kStr);
+ static_assert(__builtin_char_memchr(kStr, '\0', 5) == nullptr);
+ static_assert(__builtin_char_memchr(kStr, '\0', 6) == kStr + 5);
+ static_assert(__builtin_char_memchr(kStr, '\xff', 8) == kStr + 4);
+ static_assert(__builtin_char_memchr(kStr, '\xff' + 256, 8) == kStr + 4);
+ static_assert(__builtin_char_memchr(kStr, '\xff' - 256, 8) == kStr + 4);
+ static_assert(__builtin_char_memchr(kFoo, 'x', 3) == nullptr);
+ static_assert(__builtin_char_memchr(kFoo, 'x', 4) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
+ static_assert(__builtin_char_memchr(nullptr, 'x', 3) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
+ static_assert(__builtin_char_memchr(nullptr, 'x', 0) == nullptr); // FIXME: Should we reject this?
+
+ static_assert(*__builtin_char_memchr(kStr, '\xff', 8) == '\xff');
+ constexpr bool char_memchr_mutable() {
+ char buffer[] = "mutable";
+ *__builtin_char_memchr(buffer, 't', 8) = 'r';
+ *__builtin_char_memchr(buffer, 'm', 8) = 'd';
+ return __builtin_strcmp(buffer, "durable") == 0;
+ }
+ static_assert(char_memchr_mutable());
+
constexpr bool a = !strchr("hello", 'h'); // expected-error {{constant expression}} expected-note {{non-constexpr function 'strchr' cannot be used in a constant expression}}
constexpr bool b = !memchr("hello", 'h', 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'memchr' cannot be used in a constant expression}}
}
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