ychen created this revision.
ychen added a reviewer: rsmith.
ychen requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
1. Skip diagnosing all pointer-like parameters.
2. Replace `Context.hasSameUnqualifiedType` with `Context.hasSimilarType`.
3. Add corresponding tests.
After some thoughts, I think we could add the following extension in the
future (probably under an additional flag such as `-Wcast-function-type=2)
according to user feedbacks for the reasons: 1) users could use
`void(*)(void)` to explicitly override checks (for example:
https://trac.webkit.org/changeset/231565/webkit); 2) these checks could
hide real bugs that users may want to catch; 3) using `void(*)(void)`
makes following extension worthwhile only when a codebase uses these
patterns on a large scale which seems unlikely.
(GCC does not do the following)
- allow integer promotion (`void(int)` -> `void(char)`)
- allow arbitrary pointer-to-member conversion
- allow parameter counts mismatch
the use pattern is "passing an extra (unwanted) parameter to callbacks"
https://bugs.freedesktop.org/show_bug.cgi?id=107349#c0
Thoughts?
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D99903
Files:
clang/lib/Sema/SemaCast.cpp
clang/test/Sema/warn-cast-function-type.c
clang/test/Sema/warn-cast-function-type.m
clang/test/SemaCXX/warn-cast-function-type.cpp
Index: clang/test/SemaCXX/warn-cast-function-type.cpp
===================================================================
--- clang/test/SemaCXX/warn-cast-function-type.cpp
+++ clang/test/SemaCXX/warn-cast-function-type.cpp
@@ -1,7 +1,8 @@
-// RUN: %clang_cc1 -x c++ %s -fblocks -fsyntax-only -Wcast-function-type -triple x86_64-- -verify
+// RUN: %clang_cc1 -x c++ -std=c++11 %s -fblocks -fsyntax-only -Wcast-function-type -triple x86_64-- -verify
-int x(long);
+using nullptr_t = decltype(nullptr);
+int x(long);
typedef int (f1)(long);
typedef int (f2)(void*);
typedef int (f3)(...);
@@ -19,13 +20,39 @@
f6 *f;
f7 *g;
-struct S
-{
- void foo (int*);
- void bar (int);
-};
+struct S1 { void foo(int *); };
+struct S2 {};
+
+typedef void (S1::*pmf1)(int);
+typedef float S1::*pm1;
+typedef const float S1::*pm2;
+
+void y(long *);
+typedef void(pf1)(long **);
+typedef void(pf2)(long &);
+typedef void(pf3)(void (^)(long));
+typedef void(pf4)(nullptr_t);
-typedef void (S::*mf)(int);
+void z(long &);
+typedef void(pf5)(long **);
+typedef void(pf6)(long &);
+typedef void(pf7)(void (^)(long));
+typedef void(pf8)(nullptr_t);
+
+void u(pm1);
+typedef void(pf9)(pm2);
+typedef void(pf10)(nullptr_t);
+
+pf1 *p1;
+pf2 *p2;
+pf3 *p3;
+pf4 *p4;
+pf5 *p5;
+pf6 *p6;
+pf7 *p7;
+pf8 *p8;
+pf9 *p9;
+pf10 *p10;
void foo() {
a = (f1 *)x;
@@ -37,11 +64,22 @@
f = (f6 *)x; /* expected-warning {{cast from 'int (*)(long)' to 'f6 *' (aka 'int (*)(long, int)') converts to incompatible function type}} */
g = (f7 *)x;
- mf p1 = (mf)&S::foo; /* expected-warning {{cast from 'void (S::*)(int *)' to 'mf' (aka 'void (S::*)(int)') converts to incompatible function type}} */
+ pmf1 pm1 = (pmf1)&S1::foo; /* expected-warning {{cast from 'void (S1::*)(int *)' to 'pmf1' (aka 'void (S1::*)(int)') converts to incompatible function type}} */
f8 f2 = (f8)x; /* expected-warning {{cast from 'int (long)' to 'f8' (aka 'int (&)(long, int)') converts to incompatible function type}} */
(void)f2;
- int (^y)(long);
- f = (f6 *)y; /* expected-warning {{cast from 'int (^)(long)' to 'f6 *' (aka 'int (*)(long, int)') converts to incompatible function type}} */
+ int (^bb)(long);
+ f = (f6 *)bb; /* expected-warning {{cast from 'int (^)(long)' to 'f6 *' (aka 'int (*)(long, int)') converts to incompatible function type}} */
+
+ p1 = (pf1 *)y;
+ p2 = (pf2 *)y; /* expected-warning {{cast from 'void (*)(long *)' to 'pf2 *' (aka 'void (*)(long &)') converts to incompatible function type}} */
+ p3 = (pf3 *)y;
+ p4 = (pf4 *)y;
+ p5 = (pf5 *)z; /* expected-warning {{cast from 'void (*)(long &)' to 'pf5 *' (aka 'void (*)(long **)') converts to incompatible function type}} */
+ p6 = (pf6 *)z;
+ p7 = (pf7 *)z; /* expected-warning {{cast from 'void (*)(long &)' to 'pf7 *' (aka 'void (*)(void (^)(long))') converts to incompatible function type}} */
+ p8 = (pf8 *)z; /* expected-warning {{cast from 'void (*)(long &)' to 'pf8 *' (aka 'void (*)(nullptr_t)') converts to incompatible function type}} */
+ p9 = (pf9 *)u;
+ p10 = (pf10 *)u;
}
Index: clang/test/Sema/warn-cast-function-type.m
===================================================================
--- /dev/null
+++ clang/test/Sema/warn-cast-function-type.m
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 %s -fsyntax-only -Wcast-function-type -verify
+
+// expected-no-diagnostics
+
+int x(long*);
+
+typedef int (f1)(id);
+
+f1 *a;
+
+void foo(void) {
+ a = (f1 *)x;
+}
Index: clang/test/Sema/warn-cast-function-type.c
===================================================================
--- clang/test/Sema/warn-cast-function-type.c
+++ clang/test/Sema/warn-cast-function-type.c
@@ -9,6 +9,8 @@
typedef void (f5)(void);
typedef int (f6)(long, int);
typedef int (f7)(long,...);
+typedef int (f8)(int);
+typedef int (f9)(unsigned long);
f1 *a;
f2 *b;
@@ -17,6 +19,8 @@
f5 *e;
f6 *f;
f7 *g;
+f8 *h;
+f9 *i;
void foo(void) {
a = (f1 *)x;
@@ -26,4 +30,6 @@
e = (f5 *)x;
f = (f6 *)x; /* expected-warning {{cast from 'int (*)(long)' to 'f6 *' (aka 'int (*)(long, int)') converts to incompatible function type}} */
g = (f7 *)x;
+ h = (f8 *)x; /* expected-warning {{cast from 'int (*)(long)' to 'f8 *' (aka 'int (*)(int)') converts to incompatible function type}} */
+ i = (f9 *)x;
}
Index: clang/lib/Sema/SemaCast.cpp
===================================================================
--- clang/lib/Sema/SemaCast.cpp
+++ clang/lib/Sema/SemaCast.cpp
@@ -1038,7 +1038,14 @@
static bool argTypeIsABIEquivalent(QualType SrcType, QualType DestType,
ASTContext &Context) {
- if (SrcType->isPointerType() && DestType->isPointerType())
+ if (SrcType->hasPointerRepresentation() &&
+ DestType->hasPointerRepresentation() &&
+ SrcType->isReferenceType() == DestType->isReferenceType())
+ return true;
+
+ // nullptr_t is compatible with member pointers.
+ if ((SrcType->isNullPtrType() && DestType->isMemberPointerType()) ||
+ (DestType->isNullPtrType() && SrcType->isMemberPointerType()))
return true;
// Allow integral type mismatch if their size are equal.
@@ -1047,7 +1054,7 @@
Context.getTypeInfoInChars(DestType).Width)
return true;
- return Context.hasSameUnqualifiedType(SrcType, DestType);
+ return Context.hasSimilarType(SrcType, DestType);
}
static bool checkCastFunctionType(Sema &Self, const ExprResult &SrcExpr,
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