[clang][Fuchsia] Use unsigned int for wint_t on *-fuchsia targets

[frobtech]

This aligns Fuchsia targets with other similar OS targets such as
Linux. Fuchsia's libc already uses unsigned rather than the
compiler-provided WINT_TYPE macro for its wint_t typedef, so
this just makes the compiler consistent with the OS's actual ABI.
The only known manifestation of the mismatch is -Wformat warnings
for %lc no matching wint_t arguments.

The closest thing I could see to existing tests for each target's
wint_t type setting was the predefine tests that check various
macros including WINT_TYPE on a per-machine and/or per-OS
basis. While the setting is done per-OS in most of the target
implementations rather than actually varying by machine, the only
existing tests for WINT_TYPE are in per-machine checks that
are also wholly or partly tagged as per-OS. x86_64 and riscv64
tests for respective *-linux-gnu targets now check for the same
definitions in the respective *-fuchsia targets. WINT_TYPE
is not among the type checked in the aarch64 tests and those lack
a section that's specifically tested for aarch64-linux-gnu; if
such is added then it can similarly be made to check for most or
all of the same value on aarch64-fuchsia as aarch64-linux-gnu.
But since the actual implementation of choosing the type is done
per-OS and not per-machine for the three machines with Fuchsia
target support, the x86 and riscv64 tests are already redundantly
testing that same code and seem sufficient.

[llvmbot]

@llvm/pr-subscribers-clang

Author: Roland McGrath (frobtech)

Changes

This aligns Fuchsia targets with other similar OS targets such as
Linux. Fuchsia's libc already uses unsigned rather than the
compiler-provided WINT_TYPE macro for its wint_t typedef, so
this just makes the compiler consistent with the OS's actual ABI.
The only known manifestation of the mismatch is -Wformat warnings
for %lc no matching wint_t arguments.

The closest thing I could see to existing tests for each target's
wint_t type setting was the predefine tests that check various
macros including WINT_TYPE on a per-machine and/or per-OS
basis. While the setting is done per-OS in most of the target
implementations rather than actually varying by machine, the only
existing tests for WINT_TYPE are in per-machine checks that
are also wholly or partly tagged as per-OS. x86_64 and riscv64
tests for respective *-linux-gnu targets now check for the same
definitions in the respective *-fuchsia targets. WINT_TYPE
is not among the type checked in the aarch64 tests and those lack
a section that's specifically tested for aarch64-linux-gnu; if
such is added then it can similarly be made to check for most or
all of the same value on aarch64-fuchsia as aarch64-linux-gnu.
But since the actual implementation of choosing the type is done
per-OS and not per-machine for the three machines with Fuchsia
target support, the x86 and riscv64 tests are already redundantly
testing that same code and seem sufficient.

---

Full diff: https://github.com/llvm/llvm-project/pull/95499.diff

3 Files Affected:

• (modified) clang/lib/Basic/Targets/OSTargets.h (+1)
• (modified) clang/test/Preprocessor/init-x86.c (+1)
• (modified) clang/test/Preprocessor/init.c (+2)

diff --git a/clang/lib/Basic/Targets/OSTargets.h b/clang/lib/Basic/Targets/OSTargets.h
index 4366c1149e405..5f27c3469f861 100644
--- a/clang/lib/Basic/Targets/OSTargets.h
+++ b/clang/lib/Basic/Targets/OSTargets.h
@@ -868,6 +868,7 @@ class LLVM_LIBRARY_VISIBILITY FuchsiaTargetInfo : public OSTargetInfo<Target> {
 public:
   FuchsiaTargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : OSTargetInfo<Target>(Triple, Opts) {
+    this->WIntType = TargetInfo::UnsignedInt;
     this->MCountName = "__mcount";
     this->TheCXXABI.set(TargetCXXABI::Fuchsia);
   }
diff --git a/clang/test/Preprocessor/init-x86.c b/clang/test/Preprocessor/init-x86.c
index 1268419e18a5c..6f5aa5674e48e 100644
--- a/clang/test/Preprocessor/init-x86.c
+++ b/clang/test/Preprocessor/init-x86.c
@@ -999,6 +999,7 @@
 // X32:#define __x86_64__ 1
 
 // RUN: %clang_cc1 -E -dM -ffreestanding -fgnuc-version=4.2.1 -triple=x86_64-pc-linux-gnu < /dev/null | FileCheck -match-full-lines -check-prefix X86_64-LINUX %s
+// RUN: %clang_cc1 -E -dM -ffreestanding -fgnuc-version=4.2.1 -triple=x86_64-unknown-fuchsia < /dev/null | FileCheck -match-full-lines -check-prefix X86_64-LINUX %s
 //
 // X86_64-LINUX:#define _LP64 1
 // X86_64-LINUX:#define __BIGGEST_ALIGNMENT__ 16
diff --git a/clang/test/Preprocessor/init.c b/clang/test/Preprocessor/init.c
index 2641fee940231..6e7c0ea5c730b 100644
--- a/clang/test/Preprocessor/init.c
+++ b/clang/test/Preprocessor/init.c
@@ -2527,6 +2527,8 @@
 // RUN:   | FileCheck -match-full-lines -check-prefix=RISCV64 %s
 // RUN: %clang_cc1 -E -dM -ffreestanding -fgnuc-version=4.2.1 -triple=riscv64-unknown-linux < /dev/null \
 // RUN:   | FileCheck -match-full-lines -check-prefixes=RISCV64,RISCV64-LINUX %s
+// RUN: %clang_cc1 -E -dM -ffreestanding -fgnuc-version=4.2.1 -triple=riscv64-unknown-fuchsia < /dev/null \
+// RUN:   | FileCheck -match-full-lines -check-prefixes=RISCV64 %s
 // RISCV64: #define _LP64 1
 // RISCV64: #define __ATOMIC_ACQUIRE 2
 // RISCV64: #define __ATOMIC_ACQ_REL 4