Merge pull request #39900 from al45tair/problem/84571859

[Runtime] Add format string attributes.

Author: al45tair

include/swift/Demangling/TypeLookupError.h

@@ -209,6 +209,7 @@ static TypeLookupError TypeLookupErrorImpl(const char *fmt, Args... args) {
     char *str;
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wformat-security"
+#pragma clang diagnostic ignored "-Wformat-nonliteral"
     swift_asprintf(&str, fmt, args...);
 #pragma clang diagnostic pop
     return str;

include/swift/Runtime/Config.h

@@ -226,6 +226,22 @@ extern uintptr_t __COMPATIBILITY_LIBRARIES_CANNOT_CHECK_THE_IS_SWIFT_BIT_DIRECTL
 // so changing this value is not sufficient.
 #define SWIFT_DEFAULT_LLVM_CC llvm::CallingConv::C
 
+// SWIFT_FORMAT(fmt,first) marks a function as taking a format string argument
+// at argument `fmt`, with the first argument for the format string as `first`.
+#if __has_attribute(format)
+#define SWIFT_FORMAT(fmt,first) __attribute__((format(printf, fmt, first)))
+#else
+#define SWIFT_FORMAT(fmt,first)
+#endif
+
+// SWIFT_VFORMAT(fmt) marks a function as taking a format string argument at
+// argument `fmt`, with the arguments in a `va_list`.
+#if __has_attribute(format)
+#define SWIFT_VFORMAT(fmt)      __attribute__((format(printf, fmt, 0)))
+#else
+#define SWIFT_VFORMAT(fmt)
+#endif
+
 // Pointer authentication.
 #if __has_feature(ptrauth_calls)
 #define SWIFT_PTRAUTH 1

include/swift/Runtime/Debug.h

@@ -85,15 +85,18 @@ static inline void crash(const char *message) {
 // swift::fatalError() halts with a crash log message, 
 // but makes no attempt to preserve register state.
 SWIFT_RUNTIME_ATTRIBUTE_NORETURN
+SWIFT_FORMAT(2, 3)
 extern void
 fatalError(uint32_t flags, const char *format, ...);
 
 /// swift::warning() emits a warning from the runtime.
 extern void
+SWIFT_VFORMAT(2)
 warningv(uint32_t flags, const char *format, va_list args);
 
 /// swift::warning() emits a warning from the runtime.
 extern void
+SWIFT_FORMAT(2, 3)
 warning(uint32_t flags, const char *format, ...);
 
 // swift_dynamicCastFailure halts using fatalError()

stdlib/public/runtime/DynamicCast.cpp

@@ -126,7 +126,7 @@ static HeapObject * getNonNullSrcObject(OpaqueValue *srcValue,
 
   std::string srcTypeName = nameForMetadata(srcType);
   std::string destTypeName = nameForMetadata(destType);
-  const char *msg = "Found unexpected null pointer value"
+  const char * const msg = "Found unexpected null pointer value"
                     " while trying to cast value of type '%s' (%p)"
                     " to '%s' (%p)%s\n";
   if (runtime::bincompat::unexpectedObjCNullWhileCastingIsFatal()) {

stdlib/public/runtime/Metadata.cpp

@@ -5751,7 +5751,7 @@ diagnoseMetadataDependencyCycle(const Metadata *start,
                             &details);
   }
 
-  fatalError(0, diagnostic.c_str());
+  fatalError(0, "%s", diagnostic.c_str());
 }
 
 /// Check whether the given metadata dependency is satisfied, and if not,

stdlib/public/runtime/ReflectionMirror.cpp

@@ -339,6 +339,7 @@ static bool _shouldReportMissingReflectionMetadataWarnings() {
 /// at runtime. This is usually mostly harmless, but it's good to alert
 /// users that it happens.
 static void
+SWIFT_FORMAT(1, 2)
 missing_reflection_metadata_warning(const char *fmt, ...) {
   bool shouldWarn =
     SWIFT_LAZY_CONSTANT(_shouldReportMissingReflectionMetadataWarnings());