r355662 - [ObjC] Emit a boxed expression as a compile-time constant if the
Akira Hatanaka via cfe-commits
cfe-commits at lists.llvm.org
Thu Mar 7 20:45:37 PST 2019
Author: ahatanak
Date: Thu Mar 7 20:45:37 2019
New Revision: 355662
URL: http://llvm.org/viewvc/llvm-project?rev=355662&view=rev
Log:
[ObjC] Emit a boxed expression as a compile-time constant if the
expression inside the parentheses is a valid UTF-8 string literal.
Previously clang emitted an expression like @("abc") as a message send
to stringWithUTF8String. This commit makes clang emit the boxed
expression as a compile-time constant instead.
This commit also has the effect of silencing the nullable-to-nonnull
conversion warning clang started emitting after r317727, which
originally motivated this commit (see https://oleb.net/2018/@keypath).
rdar://problem/42684601
Differential Revision: https://reviews.llvm.org/D58729
Modified:
cfe/trunk/include/clang/AST/ExprObjC.h
cfe/trunk/include/clang/Basic/DiagnosticGroups.td
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/AST/ExprConstant.cpp
cfe/trunk/lib/CodeGen/CGExprConstant.cpp
cfe/trunk/lib/CodeGen/CGObjC.cpp
cfe/trunk/lib/Sema/SemaExprObjC.cpp
cfe/trunk/test/CodeGenObjC/boxing.m
cfe/trunk/test/SemaObjC/boxing-illegal.m
cfe/trunk/test/SemaObjC/objc-literal-sig.m
cfe/trunk/test/SemaObjC/transfer-boxed-string-nullability.m
cfe/trunk/test/SemaObjCXX/literals.mm
Modified: cfe/trunk/include/clang/AST/ExprObjC.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/ExprObjC.h?rev=355662&r1=355661&r2=355662&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/ExprObjC.h (original)
+++ cfe/trunk/include/clang/AST/ExprObjC.h Thu Mar 7 20:45:37 2019
@@ -138,6 +138,12 @@ public:
return BoxingMethod;
}
+ // Indicates whether this boxed expression can be emitted as a compile-time
+ // constant.
+ bool isExpressibleAsConstantInitializer() const {
+ return !BoxingMethod && SubExpr;
+ }
+
SourceLocation getAtLoc() const { return Range.getBegin(); }
SourceLocation getBeginLoc() const LLVM_READONLY { return Range.getBegin(); }
Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=355662&r1=355661&r2=355662&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Thu Mar 7 20:45:37 2019
@@ -404,6 +404,7 @@ def ObjCPointerIntrospectPerformSelector
def ObjCPointerIntrospect : DiagGroup<"deprecated-objc-pointer-introspection", [ObjCPointerIntrospectPerformSelector]>;
def ObjCMultipleMethodNames : DiagGroup<"objc-multiple-method-names">;
def ObjCFlexibleArray : DiagGroup<"objc-flexible-array">;
+def ObjCBoxing : DiagGroup<"objc-boxing">;
def OpenCLUnsupportedRGBA: DiagGroup<"opencl-unsupported-rgba">;
def DeprecatedObjCIsaUsage : DiagGroup<"deprecated-objc-isa-usage">;
def ExplicitInitializeCall : DiagGroup<"explicit-initialize-call">;
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=355662&r1=355661&r2=355662&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Thu Mar 7 20:45:37 2019
@@ -918,6 +918,9 @@ def err_inconsistent_ivar_count : Error<
"inconsistent number of instance variables specified">;
def warn_undef_method_impl : Warning<"method definition for %0 not found">,
InGroup<DiagGroup<"incomplete-implementation">>;
+def warn_objc_boxing_invalid_utf8_string : Warning<
+ "string is ill-formed as UTF-8 and will become a null %0 when boxed">,
+ InGroup<ObjCBoxing>;
def warn_conflicting_overriding_ret_types : Warning<
"conflicting return type in "
Modified: cfe/trunk/lib/AST/ExprConstant.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=355662&r1=355661&r2=355662&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprConstant.cpp (original)
+++ cfe/trunk/lib/AST/ExprConstant.cpp Thu Mar 7 20:45:37 2019
@@ -1743,6 +1743,8 @@ static bool IsGlobalLValue(APValue::LVal
case Expr::CXXTypeidExprClass:
case Expr::CXXUuidofExprClass:
return true;
+ case Expr::ObjCBoxedExprClass:
+ return cast<ObjCBoxedExpr>(E)->isExpressibleAsConstantInitializer();
case Expr::CallExprClass:
return IsStringLiteralCall(cast<CallExpr>(E));
// For GCC compatibility, &&label has static storage duration.
@@ -5794,6 +5796,8 @@ public:
bool VisitObjCStringLiteral(const ObjCStringLiteral *E)
{ return Success(E); }
bool VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
+ if (E->isExpressibleAsConstantInitializer())
+ return Success(E);
if (Info.noteFailure())
EvaluateIgnoredValue(Info, E->getSubExpr());
return Error(E);
Modified: cfe/trunk/lib/CodeGen/CGExprConstant.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprConstant.cpp?rev=355662&r1=355661&r2=355662&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprConstant.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprConstant.cpp Thu Mar 7 20:45:37 2019
@@ -1613,6 +1613,7 @@ private:
ConstantLValue VisitConstantExpr(const ConstantExpr *E);
ConstantLValue VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
ConstantLValue VisitStringLiteral(const StringLiteral *E);
+ ConstantLValue VisitObjCBoxedExpr(const ObjCBoxedExpr *E);
ConstantLValue VisitObjCEncodeExpr(const ObjCEncodeExpr *E);
ConstantLValue VisitObjCStringLiteral(const ObjCStringLiteral *E);
ConstantLValue VisitPredefinedExpr(const PredefinedExpr *E);
@@ -1775,10 +1776,24 @@ ConstantLValueEmitter::VisitObjCEncodeEx
return CGM.GetAddrOfConstantStringFromObjCEncode(E);
}
+static ConstantLValue emitConstantObjCStringLiteral(const StringLiteral *S,
+ QualType T,
+ CodeGenModule &CGM) {
+ auto C = CGM.getObjCRuntime().GenerateConstantString(S);
+ return C.getElementBitCast(CGM.getTypes().ConvertTypeForMem(T));
+}
+
ConstantLValue
ConstantLValueEmitter::VisitObjCStringLiteral(const ObjCStringLiteral *E) {
- auto C = CGM.getObjCRuntime().GenerateConstantString(E->getString());
- return C.getElementBitCast(CGM.getTypes().ConvertTypeForMem(E->getType()));
+ return emitConstantObjCStringLiteral(E->getString(), E->getType(), CGM);
+}
+
+ConstantLValue
+ConstantLValueEmitter::VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
+ assert(E->isExpressibleAsConstantInitializer() &&
+ "this boxed expression can't be emitted as a compile-time constant");
+ auto *SL = cast<StringLiteral>(E->getSubExpr()->IgnoreParenCasts());
+ return emitConstantObjCStringLiteral(SL, E->getType(), CGM);
}
ConstantLValue
Modified: cfe/trunk/lib/CodeGen/CGObjC.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGObjC.cpp?rev=355662&r1=355661&r2=355662&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGObjC.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGObjC.cpp Thu Mar 7 20:45:37 2019
@@ -14,6 +14,7 @@
#include "CGObjCRuntime.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
+#include "ConstantEmitter.h"
#include "TargetInfo.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
@@ -60,7 +61,12 @@ CodeGenFunction::EmitObjCBoxedExpr(const
// Get the method.
const ObjCMethodDecl *BoxingMethod = E->getBoxingMethod();
const Expr *SubExpr = E->getSubExpr();
- assert(BoxingMethod && "BoxingMethod is null");
+
+ if (E->isExpressibleAsConstantInitializer()) {
+ ConstantEmitter ConstEmitter(CGM);
+ return ConstEmitter.tryEmitAbstract(E, E->getType());
+ }
+
assert(BoxingMethod->isClassMethod() && "BoxingMethod must be a class method");
Selector Sel = BoxingMethod->getSelector();
Modified: cfe/trunk/lib/Sema/SemaExprObjC.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprObjC.cpp?rev=355662&r1=355661&r2=355662&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExprObjC.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExprObjC.cpp Thu Mar 7 20:45:37 2019
@@ -25,6 +25,7 @@
#include "clang/Sema/Scope.h"
#include "clang/Sema/ScopeInfo.h"
#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/ConvertUTF.h"
using namespace clang;
using namespace sema;
@@ -524,6 +525,30 @@ ExprResult Sema::BuildObjCBoxedExpr(Sour
NSStringPointer = Context.getObjCObjectPointerType(NSStringObject);
}
+ // The boxed expression can be emitted as a compile time constant if it is
+ // a string literal whose character encoding is compatible with UTF-8.
+ if (auto *CE = dyn_cast<ImplicitCastExpr>(ValueExpr))
+ if (CE->getCastKind() == CK_ArrayToPointerDecay)
+ if (auto *SL =
+ dyn_cast<StringLiteral>(CE->getSubExpr()->IgnoreParens())) {
+ assert((SL->isAscii() || SL->isUTF8()) &&
+ "unexpected character encoding");
+ StringRef Str = SL->getString();
+ const llvm::UTF8 *StrBegin = Str.bytes_begin();
+ const llvm::UTF8 *StrEnd = Str.bytes_end();
+ // Check that this is a valid UTF-8 string.
+ if (llvm::isLegalUTF8String(&StrBegin, StrEnd)) {
+ BoxedType = Context.getAttributedType(
+ AttributedType::getNullabilityAttrKind(
+ NullabilityKind::NonNull),
+ NSStringPointer, NSStringPointer);
+ return new (Context) ObjCBoxedExpr(CE, BoxedType, nullptr, SR);
+ }
+
+ Diag(SL->getBeginLoc(), diag::warn_objc_boxing_invalid_utf8_string)
+ << NSStringPointer << SL->getSourceRange();
+ }
+
if (!StringWithUTF8StringMethod) {
IdentifierInfo *II = &Context.Idents.get("stringWithUTF8String");
Selector stringWithUTF8String = Context.Selectors.getUnarySelector(II);
Modified: cfe/trunk/test/CodeGenObjC/boxing.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenObjC/boxing.m?rev=355662&r1=355661&r2=355662&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenObjC/boxing.m (original)
+++ cfe/trunk/test/CodeGenObjC/boxing.m Thu Mar 7 20:45:37 2019
@@ -53,6 +53,9 @@ typedef signed char BOOL;
+ (id)stringWithUTF8String:(const char *)nullTerminatedCString;
@end
+// CHECK: [[V0:%.*]] = type opaque
+// CHECK: [[STRUCT_NSCONSTANT_STRING_TAG:%.*]] = type { i32*, i32, i8*, i64 }
+
// CHECK: [[WithIntMeth:@.*]] = private unnamed_addr constant [15 x i8] c"numberWithInt:\00"
// CHECK: [[WithIntSEL:@.*]] = private externally_initialized global i8* getelementptr inbounds ([15 x i8], [15 x i8]* [[WithIntMeth]]
// CHECK: [[WithCharMeth:@.*]] = private unnamed_addr constant [16 x i8] c"numberWithChar:\00"
@@ -65,8 +68,12 @@ typedef signed char BOOL;
// CHECK: [[WithUnsignedIntegerSEL:@.*]] = private externally_initialized global i8* getelementptr inbounds ([27 x i8], [27 x i8]* [[WithUnsignedIntegerMeth]]
// CHECK: [[stringWithUTF8StringMeth:@.*]] = private unnamed_addr constant [22 x i8] c"stringWithUTF8String:\00"
// CHECK: [[stringWithUTF8StringSEL:@.*]] = private externally_initialized global i8* getelementptr inbounds ([22 x i8], [22 x i8]* [[stringWithUTF8StringMeth]]
+// CHECK: [[STR0:.*]] = private unnamed_addr constant [4 x i8] c"abc\00", section "__TEXT,__cstring,cstring_literals", align 1
+// CHECK: [[UNNAMED_CFSTRING:.*]] = private global [[STRUCT_NSCONSTANT_STRING_TAG]] { i32* getelementptr inbounds ([0 x i32], [0 x i32]* @__CFConstantStringClassReference, i32 0, i32 0), i32 1992, i8* getelementptr inbounds ([4 x i8], [4 x i8]* [[STR0]], i32 0, i32 0), i64 3 }, section "__DATA,__cfstring", align 8
int main() {
+ // CHECK: [[T:%.*]] = alloca [[V0]]*, align 8
+
// CHECK: load i8*, i8** [[WithIntSEL]]
int i; @(i);
// CHECK: load i8*, i8** [[WithCharSEL]]
@@ -92,4 +99,7 @@ int main() {
Color col = Red;
// CHECK: load i8*, i8** [[WithIntegerSEL]]
@(col);
+
+ // CHECK: store [[V0]]* bitcast ([[STRUCT_NSCONSTANT_STRING_TAG]]* [[UNNAMED_CFSTRING]] to [[V0]]*), [[V0]]** [[T]], align 8
+ NSString *t = @("abc");
}
Modified: cfe/trunk/test/SemaObjC/boxing-illegal.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/boxing-illegal.m?rev=355662&r1=355661&r2=355662&view=diff
==============================================================================
--- cfe/trunk/test/SemaObjC/boxing-illegal.m (original)
+++ cfe/trunk/test/SemaObjC/boxing-illegal.m Thu Mar 7 20:45:37 2019
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify -Wattributes %s
+// RUN: %clang_cc1 -fsyntax-only -verify -Wattributes -fpascal-strings %s
typedef long NSInteger;
typedef unsigned long NSUInteger;
@@ -57,6 +57,19 @@ void testEnum(void *p) {
box = @(*(enum ForwE*)p); // expected-error {{incomplete type 'enum ForwE' used in a boxed expression}}
}
+ at interface NSString
+ at end
+
+void testStringLiteral() {
+ NSString *s;
+ s = @("abc");
+ s = @(u8"abc");
+ s = @(u"abc"); // expected-error {{illegal type 'unsigned short *' used in a boxed expression}}
+ s = @(U"abc"); // expected-error {{illegal type 'unsigned int *' used in a boxed expression}}
+ s = @(L"abc"); // expected-error {{illegal type 'int *' used in a boxed expression}}
+ s = @("\pabc"); // expected-error {{illegal type 'unsigned char *' used in a boxed expression}}
+}
+
// rdar://13333205
@class NSMutableDictionary;
Modified: cfe/trunk/test/SemaObjC/objc-literal-sig.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/objc-literal-sig.m?rev=355662&r1=355661&r2=355662&view=diff
==============================================================================
--- cfe/trunk/test/SemaObjC/objc-literal-sig.m (original)
+++ cfe/trunk/test/SemaObjC/objc-literal-sig.m Thu Mar 7 20:45:37 2019
@@ -39,6 +39,8 @@ typedef _Bool BOOL;
// All tests are doubled to make sure that a bad method is not saved
// and then used un-checked.
+const char *getStr(void);
+
void test_sig() {
(void)@__objc_yes; // expected-error{{literal construction method 'numberWithBool:' has incompatible signature}}
(void)@__objc_yes; // expected-error{{literal construction method 'numberWithBool:' has incompatible signature}}
@@ -46,6 +48,6 @@ void test_sig() {
id array2 = @[ @17 ]; // expected-error{{literal construction method 'arrayWithObjects:count:' has incompatible signature}}
id dict = @{ @"hello" : @17 }; // expected-error{{literal construction method 'dictionaryWithObjects:forKeys:count:' has incompatible signature}}
id dict2 = @{ @"hello" : @17 }; // expected-error{{literal construction method 'dictionaryWithObjects:forKeys:count:' has incompatible signature}}
- id str = @("hello"); // expected-error{{literal construction method 'stringWithUTF8String:' has incompatible signature}}
- id str2 = @("hello"); // expected-error{{literal construction method 'stringWithUTF8String:' has incompatible signature}}
+ id str = @(getStr()); // expected-error{{literal construction method 'stringWithUTF8String:' has incompatible signature}}
+ id str2 = @(getStr()); // expected-error{{literal construction method 'stringWithUTF8String:' has incompatible signature}}
}
Modified: cfe/trunk/test/SemaObjC/transfer-boxed-string-nullability.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/transfer-boxed-string-nullability.m?rev=355662&r1=355661&r2=355662&view=diff
==============================================================================
--- cfe/trunk/test/SemaObjC/transfer-boxed-string-nullability.m (original)
+++ cfe/trunk/test/SemaObjC/transfer-boxed-string-nullability.m Thu Mar 7 20:45:37 2019
@@ -16,13 +16,23 @@
void takesNonNull(NSString * _Nonnull ptr);
void testBoxedString() {
+ // No diagnostic emitted as this doesn't need a stringWithUTF8String message
+ // send.
+ takesNonNull(@("hey"));
+ takesNonNull(@(u8"hey"));
+
+ // If the string isn't a valid UTF-8 string, a diagnostic is emitted since the
+ // boxed expression turns into a message send.
+ takesNonNull(@(u8"\xFF")); // expected-warning {{string is ill-formed as UTF-8}}
+ takesNonNull(@(u8"\xC0\x80")); // expected-warning {{string is ill-formed as UTF-8}}
+
const char *str = "hey";
takesNonNull([NSString stringWithUTF8String:str]);
takesNonNull(@(str));
#ifndef NOWARN
- // expected-warning at -3 {{implicit conversion from nullable pointer 'NSString * _Nullable' to non-nullable pointer type 'NSString * _Nonnull'}}
- // expected-warning at -3 {{implicit conversion from nullable pointer 'NSString * _Nullable' to non-nullable pointer type 'NSString * _Nonnull'}}
-#else
- // expected-no-diagnostics
+ // expected-warning at -7 {{implicit conversion from nullable pointer 'NSString * _Nullable' to non-nullable pointer type 'NSString * _Nonnull'}}
+ // expected-warning at -7 {{implicit conversion from nullable pointer 'NSString * _Nullable' to non-nullable pointer type 'NSString * _Nonnull'}}
+ // expected-warning at -5 {{implicit conversion from nullable pointer 'NSString * _Nullable' to non-nullable pointer type 'NSString * _Nonnull'}}
+ // expected-warning at -5 {{implicit conversion from nullable pointer 'NSString * _Nullable' to non-nullable pointer type 'NSString * _Nonnull'}}
#endif
}
Modified: cfe/trunk/test/SemaObjCXX/literals.mm
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjCXX/literals.mm?rev=355662&r1=355661&r2=355662&view=diff
==============================================================================
--- cfe/trunk/test/SemaObjCXX/literals.mm (original)
+++ cfe/trunk/test/SemaObjCXX/literals.mm Thu Mar 7 20:45:37 2019
@@ -50,6 +50,9 @@ void x() {
+ (id)dictionaryWithObjects:(const id [])objects forKeys:(const id<NSCopying> [])keys count:(unsigned long)cnt;
@end
+ at interface NSString
+ at end
+
template<typename T>
struct ConvertibleTo {
operator T();
@@ -185,3 +188,8 @@ id value;
void test_dictionary_colon() {
id dict = @{ key : value };
}
+
+void testConstExpr() {
+ constexpr NSString *t0 = @"abc";
+ constexpr NSString *t1 = @("abc");
+}
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