[clang] Fix handling of "%zd" format specifier

[alexander-shaposhnikov]

Summary

This diff addresses FIXME in lib/Analysis/PrintfFormatString.cpp
and makes Clang warn on incorrect using of "%zd" format specifier.

Test plan: make check-all

[aaron.ballman]

lib/Analysis/PrintfFormatString.cpp

539

What about here?

[alexander-shaposhnikov]

Address comments

[aaron.ballman]

LGTM!

[chapuni]

cfe/trunk/test/FixIt/format.m

240 ↗

(On Diff #106726)

The warning wasn't emitted since ssize_t is int for targeting i686.
Tweaked in rL308084.

File clang/test/FixIt/format.m Line 240: format specifies type 'ssize_t *' (aka 'int *') but the argument has type 'short *'

[alexander-shaposhnikov]

@chapuni - many thanks!

[hans]

Thanks for fixing this long-standing TODO :-)

lib/Analysis/PrintfFormatString.cpp

switch (LM.getKind()) {
       case LengthModifier::AsLongLong:
       case LengthModifier::AsQuad:
         return Ctx.LongLongTy;
       case LengthModifier::AsInt64:
         return ArgType(Ctx.LongLongTy, "__int64");
       case LengthModifier::AsIntMax:
         return ArgType(Ctx.getIntMaxType(), "intmax_t");
       case LengthModifier::AsSizeT:
-        // FIXME: How to get the corresponding signed version of size_t?
-        return ArgType();
+        return ArgType(Ctx.getSignedSizeType(), "ssize_t");
       case LengthModifier::AsInt3264:
         return Ctx.getTargetInfo().getTriple().isArch64Bit()
                    ? ArgType(Ctx.LongLongTy, "__int64")
                    : ArgType(Ctx.IntTy, "__int32");
       case LengthModifier::AsPtrDiff:
         return ArgType(Ctx.getPointerDiffType(), "ptrdiff_t");
       case LengthModifier::AsAllocate:
       case LengthModifier::AsMAllocate:
switch (LM.getKind()) {
       case LengthModifier::AsLong:
         return ArgType::PtrTo(Ctx.LongTy);
       case LengthModifier::AsLongLong:
       case LengthModifier::AsQuad:
         return ArgType::PtrTo(Ctx.LongLongTy);
       case LengthModifier::AsIntMax:
         return ArgType::PtrTo(ArgType(Ctx.getIntMaxType(), "intmax_t"));
       case LengthModifier::AsSizeT:
-        return ArgType(); // FIXME: ssize_t
+        return ArgType::PtrTo(ArgType(Ctx.getSignedSizeType(), "ssize_t"));
       case LengthModifier::AsPtrDiff:
         return ArgType::PtrTo(ArgType(Ctx.getPointerDiffType(), "ptrdiff_t"));
       case LengthModifier::AsLongDouble:
         return ArgType(); // FIXME: Is this a known extension?
       case LengthModifier::AsAllocate:
       case LengthModifier::AsMAllocate:
       case LengthModifier::AsInt32:
       case LengthModifier::AsInt3264:

test/FixIt/format.m

void testSignedness(long i, unsigned long u) {
   // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:11-[[@LINE-4]]:13}:"%lu"
   // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:11-[[@LINE-4]]:13}:"%ld"
 
   printf("%+d", u); // expected-warning{{format specifies type 'int' but the argument has type 'unsigned long'}}
 
   // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:11-[[@LINE-2]]:14}:"%+ld"
 }
 
+void testSizeTypes() {
+  printf("%zu", 0.f); // expected-warning{{format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'float'}}
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:14}:"%f"
+
+  printf("%zd", 0.f); // expected-warning{{format specifies type 'ssize_t' (aka 'long') but the argument has type 'float'}}
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:14}:"%f"
+  
+  int x;
+  printf("%zn", &x); // expected-warning{{format specifies type 'ssize_t *' (aka 'long *') but the argument has type 'int *'}}
+  // 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,
     ImplicitB = 2
   } Implicit;
 
   typedef enum {
     ImplicitLLA = 0,