scudo/standalone: prepare for enabling format string checking

[dvyukov]

Summary

Move attribute((format)) to the function declarations in the header file.
It's almost pointless in the source file.
But disable the warning with -Wno-format for now
since there is a number of existing warnings.

Depends on D107984.

[dvyukov]

This change maybe a bit pointless on its own, but it makes state of scudo/standalone consistent with other sanitizers.
FTR, here is the current list of warnings:

scudo/standalone/size_class_map.h:339:24: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/size_class_map.h:339:24: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/size_class_map.h:339:24: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/size_class_map.h:339:24: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/size_class_map.h:339:24: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/secondary.h:608:7: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/secondary.h:608:45: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/secondary.h:609:7: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'unsigned int'
scudo/standalone/secondary.h:608:7: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/secondary.h:608:45: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/secondary.h:609:7: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'unsigned int'
scudo/standalone/secondary.h:608:7: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/secondary.h:608:45: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/secondary.h:609:7: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'unsigned int'
scudo/standalone/primary64.h:169:36: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'int'
scudo/standalone/primary64.h:169:36: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'int'
scudo/standalone/primary64.h:169:36: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'int'
scudo/standalone/primary64.h:169:36: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'int'
scudo/standalone/primary64.h:169:36: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'int'
scudo/standalone/primary64.h:169:36: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'int'
scudo/standalone/primary64.h:169:36: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'int'
scudo/standalone/primary64.h:169:36: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'int'
scudo/standalone/secondary.h:608:7: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/secondary.h:608:45: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/secondary.h:609:7: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'unsigned int'
scudo/standalone/secondary.h:608:7: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/secondary.h:608:45: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/secondary.h:609:7: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'unsigned int'
scudo/standalone/secondary.h:608:7: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/secondary.h:608:45: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'scudo::u32' (aka 'unsigned int')
scudo/standalone/secondary.h:609:7: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'unsigned int'
scudo/standalone/primary64.h:169:36: warning: format specifies type 'size_t' (aka 'unsigned long') but the argument has type 'int'

compiler-rt/lib/scudo/standalone/CMakeLists.txt

 add_compiler_rt_component(scudo_standalone)
 
 include_directories(../.. include)
 
 set(SCUDO_CFLAGS)
 
 list(APPEND SCUDO_CFLAGS
   -Werror=conversion
   -Wall
   -g
   -nostdinc++)
 
+# Too many existing bugs, needs cleanup.
+append_list_if(COMPILER_RT_HAS_WNO_FORMAT -Wno-format SCUDO_CFLAGS)
+
 # Remove -stdlib= which is unused when passing -nostdinc++.
 string(REGEX REPLACE "-stdlib=[a-zA-Z+]*" "" CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})
 
 append_list_if(COMPILER_RT_HAS_FVISIBILITY_HIDDEN_FLAG -fvisibility=hidden SCUDO_CFLAGS)
 
 append_list_if(COMPILER_RT_HAS_FNO_EXCEPTIONS_FLAG -fno-exceptions SCUDO_CFLAGS)
 
 append_list_if(COMPILER_RT_HAS_WNO_PEDANTIC -Wno-pedantic SCUDO_CFLAGS)

compiler-rt/lib/scudo/standalone/string_utils.h

public:
   explicit ScopedString() { String.push_back('\0'); }
   uptr length() { return String.size() - 1; }
   const char *data() { return String.data(); }
   void clear() {
     String.clear();
     String.push_back('\0');
   }
   void append(const char *Format, va_list Args);
-  void append(const char *Format, ...);
+  void append(const char *Format, ...) FORMAT(2, 3);
   void output() const { outputRaw(String.data()); }
 
 private:
   Vector<char> String;
 };
 
-int formatString(char *Buffer, uptr BufferLength, const char *Format, ...);
-void Printf(const char *Format, ...);
+int formatString(char *Buffer, uptr BufferLength, const char *Format, ...)
+    FORMAT(3, 4);
+void Printf(const char *Format, ...) FORMAT(1, 2);
 
 } // namespace scudo
 
 #endif // SCUDO_STRING_UTILS_H_

compiler-rt/lib/scudo/standalone/string_utils.cpp

void ScopedString::append(const char *Format, va_list Args) {
   String.resize(Length + AdditionalLength);
   const uptr FormattedLength = static_cast<uptr>(formatString(
       String.data() + Length, String.size() - Length, Format, ArgsCopy));
   RAW_CHECK(data()[length()] == '\0');
   RAW_CHECK(FormattedLength + 1 == AdditionalLength);
   va_end(ArgsCopy);
 }
 
-FORMAT(2, 3)
 void ScopedString::append(const char *Format, ...) {
   va_list Args;
   va_start(Args, Format);
   append(Format, Args);
   va_end(Args);
 }
 
-FORMAT(1, 2)
 void Printf(const char *Format, ...) {
   va_list Args;
   va_start(Args, Format);
   ScopedString Msg;
   Msg.append(Format, Args);
   outputRaw(Msg.data());
   va_end(Args);
 }
 
 } // namespace scudo