r285031 - [Sema][ObjC] Warn about implicitly autoreleasing out-parameters captured
Akira Hatanaka via cfe-commits
cfe-commits at lists.llvm.org
Mon Oct 24 14:45:54 PDT 2016
Author: ahatanak
Date: Mon Oct 24 16:45:54 2016
New Revision: 285031
URL: http://llvm.org/viewvc/llvm-project?rev=285031&view=rev
Log:
[Sema][ObjC] Warn about implicitly autoreleasing out-parameters captured
by blocks.
Add a new warning "-Wblock-capture-autoreleasing". The warning warns
about implicitly autoreleasing out-parameters captured by blocks which
can introduce use-after-free bugs that are hard to debug.
rdar://problem/15377548
Differential Revision: https://reviews.llvm.org/D25844
Modified:
cfe/trunk/include/clang/Basic/DiagnosticGroups.td
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/Sema/SemaExpr.cpp
cfe/trunk/test/SemaObjC/arc.m
Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=285031&r1=285030&r2=285031&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Mon Oct 24 16:45:54 2016
@@ -498,6 +498,7 @@ def AutomaticReferenceCounting : DiagGro
def ARCRepeatedUseOfWeakMaybe : DiagGroup<"arc-maybe-repeated-use-of-weak">;
def ARCRepeatedUseOfWeak : DiagGroup<"arc-repeated-use-of-weak",
[ARCRepeatedUseOfWeakMaybe]>;
+def BlockCaptureAutoReleasing : DiagGroup<"block-capture-autoreleasing">;
def ObjCBridge : DiagGroup<"bridge-cast">;
def DeallocInCategory:DiagGroup<"dealloc-in-category">;
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=285031&r1=285030&r2=285031&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Mon Oct 24 16:45:54 2016
@@ -5077,6 +5077,16 @@ def err_arc_inconsistent_property_owners
} // end "ARC and @properties" category
+def warn_block_capture_autoreleasing : Warning<
+ "block captures an autoreleasing out-parameter, which may result in "
+ "use-after-free bugs">,
+ InGroup<BlockCaptureAutoReleasing>, DefaultIgnore;
+def note_declare_parameter_autoreleasing : Note<
+ "declare the parameter __autoreleasing explicitly to suppress this warning">;
+def note_declare_parameter_strong : Note<
+ "declare the parameter __strong or capture a __block __strong variable to "
+ "keep values alive across autorelease pools">;
+
def err_arc_atomic_ownership : Error<
"cannot perform atomic operation on a pointer to type %0: type has "
"non-trivial ownership">;
Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=285031&r1=285030&r2=285031&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Mon Oct 24 16:45:54 2016
@@ -13502,6 +13502,23 @@ static bool captureInBlock(BlockScopeInf
}
return false;
}
+
+ // Warn about implicitly autoreleasing indirect parameters captured by blocks.
+ if (auto *PT = dyn_cast<PointerType>(CaptureType)) {
+ QualType PointeeTy = PT->getPointeeType();
+ if (isa<ObjCObjectPointerType>(PointeeTy.getCanonicalType()) &&
+ PointeeTy.getObjCLifetime() == Qualifiers::OCL_Autoreleasing &&
+ !isa<AttributedType>(PointeeTy)) {
+ if (BuildAndDiagnose) {
+ SourceLocation VarLoc = Var->getLocation();
+ S.Diag(Loc, diag::warn_block_capture_autoreleasing);
+ S.Diag(VarLoc, diag::note_declare_parameter_autoreleasing) <<
+ FixItHint::CreateInsertion(VarLoc, "__autoreleasing");
+ S.Diag(VarLoc, diag::note_declare_parameter_strong);
+ }
+ }
+ }
+
const bool HasBlocksAttr = Var->hasAttr<BlocksAttr>();
if (HasBlocksAttr || CaptureType->isReferenceType() ||
(S.getLangOpts().OpenMP && S.IsOpenMPCapturedDecl(Var))) {
Modified: cfe/trunk/test/SemaObjC/arc.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/arc.m?rev=285031&r1=285030&r2=285031&view=diff
==============================================================================
--- cfe/trunk/test/SemaObjC/arc.m (original)
+++ cfe/trunk/test/SemaObjC/arc.m Mon Oct 24 16:45:54 2016
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -triple x86_64-apple-darwin11 -fobjc-runtime-has-weak -fsyntax-only -fobjc-arc -fblocks -verify -Wno-objc-root-class %s
+// RUN: %clang_cc1 -triple x86_64-apple-darwin11 -fobjc-runtime-has-weak -fsyntax-only -fobjc-arc -fblocks -verify -Wno-objc-root-class -Wblock-capture-autoreleasing %s
typedef unsigned long NSUInteger;
typedef const void * CFTypeRef;
@@ -808,3 +808,10 @@ int garf() {
TKAssertEqual(object, nil);
TKAssertEqual(object, (id)nil);
}
+
+void block_capture_autoreleasing(A * __autoreleasing *a, A **b) { // expected-note {{declare the parameter __autoreleasing explicitly to suppress this warning}} expected-note {{declare the parameter __strong or capture a __block __strong variable to keep values alive across autorelease pools}}
+ ^{
+ (void)*a;
+ (void)*b; // expected-warning {{block captures an autoreleasing out-parameter, which may result in use-after-free bugs}}
+ }();
+}
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