[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


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@314470 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 0 deletions

diff --git a/include/clang/Basic/TargetInfo.h b/include/clang/Basic/TargetInfo.h
index 38a7bfed87..8c3a5b229a 100644
--- a/include/clang/Basic/TargetInfo.h
+++ b/include/clang/Basic/TargetInfo.h
@@ -248,6 +248,9 @@ public:
   IntType getPtrDiffType(unsigned AddrSpace) const {
     return AddrSpace == 0 ? PtrDiffType : getPtrDiffTypeV(AddrSpace);
   }
+  IntType getUnsignedPtrDiffType(unsigned AddrSpace) const {
+    return getCorrespondingUnsignedType(getPtrDiffType(AddrSpace));
+  }
   IntType getIntPtrType() const { return IntPtrType; }
   IntType getUIntPtrType() const {
     return getCorrespondingUnsignedType(IntPtrType);