[clang] Add getUnsignedPointerDiffType method

C11 standard refers to the unsigned counterpart of the type ptrdiff_t 
in the paragraph 7.21.6.1p7 where it defines the format specifier %tu.
In Clang (in PrintfFormatString.cpp, lines 508-510) there is a FIXME for this case,
in particular, Clang didn't diagnose %tu issues at all, i.e.
it didn't emit any warnings on the code printf("%tu", 3.14).
In this diff we add a method getUnsignedPointerDiffType for getting the corresponding type
similarly to how it's already done in the other analogous cases (size_t, ssize_t, ptrdiff_t etc)
and fix -Wformat diagnostics for %tu plus the emitted fix-it as well.

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D38270

llvm-svn: 314470

1 files changed, 31 insertions, 0 deletions

diff --git a/clang/test/FixIt/format.m b/clang/test/FixIt/format.m
index c3cf2b1f3c5..40655a0e808 100644
--- a/clang/test/FixIt/format.m
+++ b/clang/test/FixIt/format.m
@@ -242,6 +242,37 @@ void testSizeTypes() {
   // see the comment in PrintfSpecifier::fixType in PrintfFormatString.cpp.
 }
 
+typedef __PTRDIFF_TYPE__ ptrdiff_t;
+#define __UNSIGNED_PTRDIFF_TYPE__                                              \
+  __typeof__(_Generic((__PTRDIFF_TYPE__)0,                                     \
+                      long long int : (unsigned long long int)0,               \
+                      long int : (unsigned long int)0,                         \
+                      int : (unsigned int)0,                                   \
+                      short : (unsigned short)0,                               \
+                      signed char : (unsigned char)0))
+
+void testPtrDiffTypes() {
+  __UNSIGNED_PTRDIFF_TYPE__ p1 = 0;
+  printf("%tu", p1);  // No warning.
+
+  printf("%tu", 0.f); // expected-warning-re{{format specifies type 'unsigned ptrdiff_t' (aka '{{.+}}') but the argument has type 'float'}}
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:14}:"%f"
+  
+  ptrdiff_t p2 = 0;
+  printf("%td", p2);  // No warning.
+
+  printf("%td", 0.f); // expected-warning-re{{format specifies type 'ptrdiff_t' (aka '{{.+}}') but the argument has type 'float'}}
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:14}:"%f"
+
+  ptrdiff_t p3 = 0;
+  printf("%tn", &p3); // No warning.
+
+  short x;
+  printf("%tn", &x); // expected-warning-re{{format specifies type 'ptrdiff_t *' (aka '{{.+}}') but the argument has type 'short *'}}
+  // PrintfSpecifier::fixType doesn't handle %n, so a fix-it is not emitted,
+  // see the comment in PrintfSpecifier::fixType in PrintfFormatString.cpp.
+}
+
 void testEnum() {
   typedef enum {
     ImplicitA = 1,