[cfe-commits] r152593 - in /cfe/trunk: include/clang/AST/Expr.h include/clang/Basic/DiagnosticSemaKinds.td lib/AST/ExprClassification.cpp lib/Sema/SemaExpr.cpp test/SemaCXX/lambda-expressions.cpp
John McCall
rjmccall at apple.com
Mon Mar 12 17:37:02 PDT 2012
Author: rjmccall
Date: Mon Mar 12 19:37:01 2012
New Revision: 152593
URL: http://llvm.org/viewvc/llvm-project?rev=152593&view=rev
Log:
Alternate fix to PR12248: put Sema in charge of special-casing
the diagnostic for assigning to a copied block capture. This has
the pleasant side-effect of letting us special-case the diagnostic
for assigning to a copied lambda capture as well, without introducing
a new non-modifiable enumerator for it.
Modified:
cfe/trunk/include/clang/AST/Expr.h
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/AST/ExprClassification.cpp
cfe/trunk/lib/Sema/SemaExpr.cpp
cfe/trunk/test/SemaCXX/lambda-expressions.cpp
Modified: cfe/trunk/include/clang/AST/Expr.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Expr.h?rev=152593&r1=152592&r2=152593&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/Expr.h (original)
+++ cfe/trunk/include/clang/AST/Expr.h Mon Mar 12 19:37:01 2012
@@ -236,7 +236,6 @@
MLV_IncompleteType,
MLV_ConstQualified,
MLV_ArrayType,
- MLV_NotBlockQualified,
MLV_ReadonlyProperty,
MLV_NoSetterProperty,
MLV_MemberFunction,
@@ -272,7 +271,6 @@
CM_RValue, // Not modifiable because it's an rvalue
CM_Function, // Not modifiable because it's a function; C++ only
CM_LValueCast, // Same as CM_RValue, but indicates GCC cast-as-lvalue ext
- CM_NotBlockQualified, // Not captured in the closure
CM_NoSetterProperty,// Implicit assignment to ObjC property without setter
CM_ConstQualified,
CM_ArrayType,
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=152593&r1=152592&r2=152593&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Mon Mar 12 19:37:01 2012
@@ -4387,6 +4387,8 @@
"vector is not assignable (contains duplicate components)">;
def err_block_decl_ref_not_modifiable_lvalue : Error<
"variable is not assignable (missing __block type specifier)">;
+def err_lambda_decl_ref_not_modifiable_lvalue : Error<
+ "variable is not assignable (captured by copy)">;
def err_typecheck_call_not_function : Error<
"called object type %0 is not a function or function pointer">;
def err_call_incomplete_return : Error<
Modified: cfe/trunk/lib/AST/ExprClassification.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprClassification.cpp?rev=152593&r1=152592&r2=152593&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprClassification.cpp (original)
+++ cfe/trunk/lib/AST/ExprClassification.cpp Mon Mar 12 19:37:01 2012
@@ -567,18 +567,8 @@
CanQualType CT = Ctx.getCanonicalType(E->getType());
// Const stuff is obviously not modifiable.
- if (CT.isConstQualified()) {
- // Special-case variables captured by blocks to get an improved
- // diagnostic.
- if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
- if (DRE->refersToEnclosingLocal() &&
- isa<VarDecl>(DRE->getDecl()) &&
- cast<VarDecl>(DRE->getDecl())->hasLocalStorage() &&
- !DRE->getDecl()->hasAttr<BlocksAttr>())
- return Cl::CM_NotBlockQualified;
- }
+ if (CT.isConstQualified())
return Cl::CM_ConstQualified;
- }
// Arrays are not modifiable, only their elements are.
if (CT->isArrayType())
@@ -645,7 +635,6 @@
case Cl::CM_Function: return MLV_NotObjectType;
case Cl::CM_LValueCast:
llvm_unreachable("CM_LValueCast and CL_LValue don't match");
- case Cl::CM_NotBlockQualified: return MLV_NotBlockQualified;
case Cl::CM_NoSetterProperty: return MLV_NoSetterProperty;
case Cl::CM_ConstQualified: return MLV_ConstQualified;
case Cl::CM_ArrayType: return MLV_ArrayType;
Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=152593&r1=152592&r2=152593&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Mon Mar 12 19:37:01 2012
@@ -7127,6 +7127,32 @@
return Base->getMethodDecl() != 0;
}
+/// Is the given expression (which must be 'const') a reference to a
+/// variable which was originally non-const, but which has become
+/// 'const' due to being captured within a block?
+enum NonConstCaptureKind { NCCK_None, NCCK_Block, NCCK_Lambda };
+static NonConstCaptureKind isReferenceToNonConstCapture(Sema &S, Expr *E) {
+ assert(E->isLValue() && E->getType().isConstQualified());
+ E = E->IgnoreParens();
+
+ // Must be a reference to a declaration from an enclosing scope.
+ DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E);
+ if (!DRE) return NCCK_None;
+ if (!DRE->refersToEnclosingLocal()) return NCCK_None;
+
+ // The declaration must be a variable which is not declared 'const'.
+ VarDecl *var = dyn_cast<VarDecl>(DRE->getDecl());
+ if (!var) return NCCK_None;
+ if (var->getType().isConstQualified()) return NCCK_None;
+ assert(var->hasLocalStorage() && "capture added 'const' to non-local?");
+
+ // Decide whether the first capture was for a block or a lambda.
+ DeclContext *DC = S.CurContext;
+ while (DC->getParent() != var->getDeclContext())
+ DC = DC->getParent();
+ return (isa<BlockDecl>(DC) ? NCCK_Block : NCCK_Lambda);
+}
+
/// CheckForModifiableLvalue - Verify that E is a modifiable lvalue. If not,
/// emit an error and return true. If so, return false.
static bool CheckForModifiableLvalue(Expr *E, SourceLocation Loc, Sema &S) {
@@ -7148,6 +7174,16 @@
case Expr::MLV_ConstQualified:
Diag = diag::err_typecheck_assign_const;
+ // Use a specialized diagnostic when we're assigning to an object
+ // from an enclosing function or block.
+ if (NonConstCaptureKind NCCK = isReferenceToNonConstCapture(S, E)) {
+ if (NCCK == NCCK_Block)
+ Diag = diag::err_block_decl_ref_not_modifiable_lvalue;
+ else
+ Diag = diag::err_lambda_decl_ref_not_modifiable_lvalue;
+ break;
+ }
+
// In ARC, use some specialized diagnostics for occasions where we
// infer 'const'. These are always pseudo-strong variables.
if (S.getLangOpts().ObjCAutoRefCount) {
@@ -7210,9 +7246,6 @@
case Expr::MLV_DuplicateVectorComponents:
Diag = diag::err_typecheck_duplicate_vector_components_not_mlvalue;
break;
- case Expr::MLV_NotBlockQualified:
- Diag = diag::err_block_decl_ref_not_modifiable_lvalue;
- break;
case Expr::MLV_ReadonlyProperty:
case Expr::MLV_NoSetterProperty:
llvm_unreachable("readonly properties should be processed differently");
Modified: cfe/trunk/test/SemaCXX/lambda-expressions.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/lambda-expressions.cpp?rev=152593&r1=152592&r2=152593&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/lambda-expressions.cpp (original)
+++ cfe/trunk/test/SemaCXX/lambda-expressions.cpp Mon Mar 12 19:37:01 2012
@@ -139,3 +139,12 @@
unsigned int result = 0;
auto l = [&]() { ++result; };
}
+
+namespace ModifyingCapture {
+ void test() {
+ int n = 0;
+ [=] {
+ n = 1; // expected-error {{variable is not assignable (captured by copy)}}
+ };
+ }
+}
More information about the cfe-commits
mailing list