Format strings: offer a cast to 'unichar' for %C in Objective-C contexts.

For most cases where a conversion specifier doesn't match an argument,
we usually guess that the conversion specifier is wrong. However, if
the argument is an integer type and the specifier is %C, it's likely
the user really did mean to print the integer as a character.

(This is more common than %c because there is no way to specify a unichar
literal -- you have to write an integer literal, such as '0x2603',
and then cast it to unichar.)

This does not change the behavior of %S, since there are fewer cases
where printing a literal Unicode *string* is necessary, but this could
easily be changed in the future.

<rdar://problem/11982013>

llvm-svn: 169400

3 files changed, 66 insertions, 3 deletions

diff --git a/clang/test/FixIt/format.m b/clang/test/FixIt/format.m
index 7957e91ba1e..58c553a0109 100644
--- a/clang/test/FixIt/format.m
+++ b/clang/test/FixIt/format.m
@@ -180,3 +180,36 @@ void multichar_constants_false_negative() {
   NSLog(@"%c", 'abcd'); // missing-warning{{format specifies type 'char' but the argument has type 'int'}}
   // CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:13}:"%d"
 }
+
+
+void test_percent_C() {
+  const unsigned short data = 'a';
+  NSLog(@"%C", data);  // no-warning
+
+  NSLog(@"%C", 0x2603);  // expected-warning{{format specifies type 'unichar' (aka 'unsigned short') but the argument has type 'int'}}
+  // CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:13}:"%d"
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:16-[[@LINE-2]]:16}:"(unsigned short)"
+
+  typedef unsigned short unichar;
+  
+  NSLog(@"%C", 0x2603);  // expected-warning{{format specifies type 'unichar' (aka 'unsigned short') but the argument has type 'int'}}
+  // CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:13}:"%d"
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:16-[[@LINE-2]]:16}:"(unichar)"
+  
+  NSLog(@"%C", data ? 0x2F : 0x2603); // expected-warning{{format specifies type 'unichar' (aka 'unsigned short') but the argument has type 'int'}}
+  // CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:13}:"%d"
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:16-[[@LINE-2]]:16}:"(unichar)("
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:36-[[@LINE-3]]:36}:")"
+
+  NSLog(@"%C", 0.0); // expected-warning{{format specifies type 'unichar' (aka 'unsigned short') but the argument has type 'double'}}
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:13}:"%f"
+  // CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-2]]:16-[[@LINE-2]]:16}:"(unichar)"
+
+  NSLog(@"%C", (char)0x2603); // expected-warning{{format specifies type 'unichar' (aka 'unsigned short') but the argument has type 'char'}}
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:13}:"%c"
+  // CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-2]]:16-[[@LINE-2]]:22}:"(unichar)"
+
+  NSLog(@"%C", 'a'); // expected-warning{{format specifies type 'unichar' (aka 'unsigned short') but the argument has type 'char'}}
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:13}:"%c"
+  // CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-2]]:16-[[@LINE-2]]:22}:"(unichar)"
+}
diff --git a/clang/test/FixIt/format.mm b/clang/test/FixIt/format.mm
new file mode 100644
index 00000000000..64c6c47b9b6
--- /dev/null
+++ b/clang/test/FixIt/format.mm
@@ -0,0 +1,30 @@
+// RUN: %clang_cc1 -fsyntax-only -fblocks -verify %s
+// RUN: %clang_cc1 -fdiagnostics-parseable-fixits -fblocks %s 2>&1 | FileCheck %s
+
+extern "C" void NSLog(id, ...);
+
+void test_percent_C() {
+  const unsigned short data = 'a';
+  NSLog(@"%C", data);  // no-warning
+
+  const wchar_t wchar_data = L'a';
+  NSLog(@"%C", wchar_data);  // expected-warning{{format specifies type 'unichar' (aka 'unsigned short') but the argument has type 'wchar_t'}}
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:16-[[@LINE-1]]:16}:"(unsigned short)"
+
+  NSLog(@"%C", 0x2603);  // expected-warning{{format specifies type 'unichar' (aka 'unsigned short') but the argument has type 'int'}}
+  // CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:13}:"%d"
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:16-[[@LINE-2]]:16}:"(unsigned short)"
+
+  typedef unsigned short unichar;
+
+  NSLog(@"%C", wchar_data);  // expected-warning{{format specifies type 'unichar' (aka 'unsigned short') but the argument has type 'wchar_t'}}
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:16-[[@LINE-1]]:16}:"(unichar)"
+  
+  NSLog(@"%C", 0x2603);  // expected-warning{{format specifies type 'unichar' (aka 'unsigned short') but the argument has type 'int'}}
+  // CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:13}:"%d"
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:16-[[@LINE-2]]:16}:"(unichar)"
+  
+  NSLog(@"%C", 0.0); // expected-warning{{format specifies type 'unichar' (aka 'unsigned short') but the argument has type 'double'}}
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:13}:"%f"
+  // CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-2]]:16-[[@LINE-2]]:16}:"(unichar)"
+}
diff --git a/clang/test/SemaObjC/format-strings-objc.m b/clang/test/SemaObjC/format-strings-objc.m
index 7faa995002d..bd33ad41a56 100644
--- a/clang/test/SemaObjC/format-strings-objc.m
+++ b/clang/test/SemaObjC/format-strings-objc.m
@@ -145,7 +145,7 @@ void test_percent_S() {
   NSLog(@"%S", ptr);  // no-warning
 
   const wchar_t* wchar_ptr = L"ab";
-  NSLog(@"%S", wchar_ptr);  // expected-warning{{format specifies type 'const unsigned short *' but the argument has type 'const wchar_t *'}}
+  NSLog(@"%S", wchar_ptr);  // expected-warning{{format specifies type 'const unichar *' (aka 'const unsigned short *') but the argument has type 'const wchar_t *'}}
 }
 
 void test_percent_ls() {
@@ -154,7 +154,7 @@ void test_percent_ls() {
   NSLog(@"%ls", ptr);  // no-warning
 
   const wchar_t* wchar_ptr = L"ab";
-  NSLog(@"%ls", wchar_ptr);  // expected-warning{{format specifies type 'const unsigned short *' but the argument has type 'const wchar_t *'}}
+  NSLog(@"%ls", wchar_ptr);  // expected-warning{{format specifies type 'const unichar *' (aka 'const unsigned short *') but the argument has type 'const wchar_t *'}}
 }
 
 void test_percent_C() {
@@ -162,7 +162,7 @@ void test_percent_C() {
   NSLog(@"%C", data);  // no-warning
 
   const wchar_t wchar_data = L'a';
-  NSLog(@"%C", wchar_data);  // expected-warning{{format specifies type 'unsigned short' but the argument has type 'wchar_t'}}
+  NSLog(@"%C", wchar_data);  // expected-warning{{format specifies type 'unichar' (aka 'unsigned short') but the argument has type 'wchar_t'}}
 }
 
 // Test that %@ works with toll-free bridging (<rdar://problem/10814120>).