lebedev.ri updated this revision to Diff 120285.
lebedev.ri added a comment.
- Rebased
- Handle `-Wsystem-headers` properly, as per irc disscussion.
It was suggested that `findMacroSpelling()` might be slow, and
`isNullPointerConstant()` should be used, but i'm not sure any of the
`NullPointerConstantKind`'s can replace direct check for `NULL` specifically...
Repository:
rL LLVM
https://reviews.llvm.org/D38954
Files:
docs/ReleaseNotes.rst
lib/Sema/Sema.cpp
test/SemaCXX/Inputs/warn-zero-nullptr.h
test/SemaCXX/warn-zero-nullptr.cpp
Index: test/SemaCXX/warn-zero-nullptr.cpp
===================================================================
--- test/SemaCXX/warn-zero-nullptr.cpp
+++ test/SemaCXX/warn-zero-nullptr.cpp
@@ -1,4 +1,10 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s -Wzero-as-null-pointer-constant -std=c++11
+// RUN: %clang_cc1 -fsyntax-only -verify %s -isystem %S/Inputs -Wzero-as-null-pointer-constant -std=c++11
+// RUN: %clang_cc1 -fsyntax-only -verify %s -isystem %S/Inputs -DSYSTEM_WARNINGS -Wzero-as-null-pointer-constant -Wsystem-headers -std=c++11
+
+#include <warn-zero-nullptr.h>
+
+#define MACRO (0)
+#define MCRO(x) (x)
struct S {};
@@ -15,13 +21,65 @@
void (*fp2)() = __null; // expected-warning{{zero as null pointer constant}}
int (S::*mp2) = __null; // expected-warning{{zero as null pointer constant}}
-void f0(void* v = 0); // expected-warning{{zero as null pointer constant}}
-void f1(void* v);
+void f0(void* v = MACRO); // expected-warning{{zero as null pointer constant}}
+void f1(void* v = NULL); // expected-warning{{zero as null pointer constant}}
+void f2(void* v = MCRO(0)); // expected-warning{{zero as null pointer constant}}
+void f3(void* v = MCRO(NULL)); // expected-warning{{zero as null pointer constant}}
+void f4(void* v = 0); // expected-warning{{zero as null pointer constant}}
+void f5(void* v);
void g() {
f1(0); // expected-warning{{zero as null pointer constant}}
}
// Warn on these too. Matches gcc and arguably makes sense.
void* pp = (decltype(nullptr))0; // expected-warning{{zero as null pointer constant}}
void* pp2 = static_cast<decltype(nullptr)>(0); // expected-warning{{zero as null pointer constant}}
+
+template <typename T> void TmplFunc0(T var) {}
+void Func0Test() {
+ TmplFunc0<int>(0);
+ TmplFunc0<int*>(0); // expected-warning {{zero as null pointer constant}}
+ TmplFunc0<void*>(0); // expected-warning {{zero as null pointer constant}}
+}
+
+// FIXME: this one should *NOT* warn.
+template <typename T> void TmplFunc1(int a, T default_value = 0) {} // expected-warning{{zero as null pointer constant}} expected-warning{{zero as null pointer constant}}
+void FuncTest() {
+ TmplFunc1<int>(0);
+ TmplFunc1<int*>(0); // expected-note {{in instantiation of default function argument expression for 'TmplFunc1<int *>' required here}}
+ TmplFunc1<void*>(0); // expected-note {{in instantiation of default function argument expression for 'TmplFunc1<void *>' required here}}
+}
+
+template<typename T>
+class TemplateClass0 {
+ public:
+ explicit TemplateClass0(T var) {}
+};
+void TemplateClass0Test() {
+ TemplateClass0<int> a(0);
+ TemplateClass0<int*> b(0); // expected-warning {{zero as null pointer constant}}
+ TemplateClass0<void*> c(0); // expected-warning {{zero as null pointer constant}}
+}
+
+template<typename T>
+class TemplateClass1 {
+ public:
+// FIXME: this one should *NOT* warn.
+ explicit TemplateClass1(int a, T default_value = 0) {} // expected-warning{{zero as null pointer constant}} expected-warning{{zero as null pointer constant}}
+};
+void IgnoreSubstTemplateType1() {
+ TemplateClass1<int> a(1);
+ TemplateClass1<int*> b(1); // expected-note {{in instantiation of default function argument expression for 'TemplateClass1<int *>' required here}}
+ TemplateClass1<void*> c(1); // expected-note {{in instantiation of default function argument expression for 'TemplateClass1<void *>' required here}}
+}
+
+#ifndef SYSTEM_WARNINGS
+// Do not warn on *any* other macros from system headers, even if they
+// expand to/their expansion contains NULL.
+void* sys_init = SYSTEM_MACRO;
+void* sys_init2 = OTHER_SYSTEM_MACRO;
+#else
+void* sys_init = SYSTEM_MACRO; // expected-warning {{zero as null pointer constant}}
+void* sys_init2 = OTHER_SYSTEM_MACRO; // expected-warning {{zero as null pointer constant}}
+#endif
Index: test/SemaCXX/Inputs/warn-zero-nullptr.h
===================================================================
--- /dev/null
+++ test/SemaCXX/Inputs/warn-zero-nullptr.h
@@ -0,0 +1,3 @@
+#define NULL (0)
+#define SYSTEM_MACRO (0)
+#define OTHER_SYSTEM_MACRO (NULL)
Index: lib/Sema/Sema.cpp
===================================================================
--- lib/Sema/Sema.cpp
+++ lib/Sema/Sema.cpp
@@ -440,6 +440,15 @@
return;
if (E->getType()->isNullPtrType())
return;
+
+ // If it is a macro from system header, and if the macro name is not "NULL",
+ // do not warn.
+ SourceLocation MaybeMacroLoc = E->getLocStart();
+ if (Diags.getSuppressSystemWarnings() &&
+ SourceMgr.isInSystemMacro(MaybeMacroLoc) &&
+ !findMacroSpelling(MaybeMacroLoc, "NULL"))
+ return;
+
// nullptr only exists from C++11 on, so don't warn on its absence earlier.
if (!getLangOpts().CPlusPlus11)
return;
Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -91,6 +91,9 @@
offset is nonzero. It also now warns about arithmetic on a null pointer
treated as a cast from integer to pointer (GNU extension).
+- ``-Wzero-as-null-pointer-constant`` was adjusted not to warn on null pointer
+ constants that originate from system macros, except ``NULL`` macro.
+
Non-comprehensive list of changes in this release
-------------------------------------------------
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