Remove _Printf_format_string_.

It was only used by MSVC which we no longer use, and it required
including sal.h (somewhat large) in compiler_specific.h (somewhat
commonly included).

clang-cl now no longer needs to process sal.h, which will help
with build times a tiny bit. We still get the format string
protection through the PRINTF_FORMAT macro.

(WPRINTF_FORMAT on the other hand is a no-op and clang-cl
seems to not check wprintf style format strings. So we do
lose some coverage here for wide strings, but we lost that
when we switched to clang-cl.)

TBR=slangley

Bug: none
Change-Id: Iab02869cb06682500ab31e1810c070708347ad64
Reviewed-on: https://chromium-review.googlesource.com/c/1494679
Commit-Queue: Nico Weber <thakis@chromium.org>
Auto-Submit: Nico Weber <thakis@chromium.org>
Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#636549}

base/compiler_specific.h

@@ -9,9 +9,6 @@
 
 #if defined(COMPILER_MSVC)
 
-// For _Printf_format_string_.
-#include <sal.h>
-
 // Macros for suppressing and disabling warnings on MSVC.
 //
 // Warning numbers are enumerated at:
@@ -33,7 +30,6 @@
 
 #else  // Not MSVC
 
-#define _Printf_format_string_
 #define MSVC_PUSH_DISABLE_WARNING(n)
 #define MSVC_POP_WARNING()
 #define MSVC_DISABLE_OPTIMIZE()
@@ -138,6 +134,7 @@
 // |dots_param| is the one-based index of the "..." parameter.
 // For v*printf functions (which take a va_list), pass 0 for dots_param.
 // (This is undocumented but matches what the system C headers do.)
+// For member functions, the implicit this parameter counts as index 1.
 #if defined(COMPILER_GCC) || defined(__clang__)
 #define PRINTF_FORMAT(format_param, dots_param) \
     __attribute__((format(printf, format_param, dots_param)))

base/strings/string_util.h

@@ -41,14 +41,9 @@ int vsnprintf(char* buffer, size_t size, const char* format, va_list arguments)
 
 // We separate the declaration from the implementation of this inline
 // function just so the PRINTF_FORMAT works.
-inline int snprintf(char* buffer,
-                    size_t size,
-                    _Printf_format_string_ const char* format,
-                    ...) PRINTF_FORMAT(3, 4);
-inline int snprintf(char* buffer,
-                    size_t size,
-                    _Printf_format_string_ const char* format,
-                    ...) {
+inline int snprintf(char* buffer, size_t size, const char* format, ...)
+    PRINTF_FORMAT(3, 4);
+inline int snprintf(char* buffer, size_t size, const char* format, ...) {
   va_list arguments;
   va_start(arguments, format);
   int result = vsnprintf(buffer, size, format, arguments);

base/strings/stringprintf.h

@@ -16,13 +16,11 @@
 namespace base {
 
 // Return a C++ string given printf-like input.
-BASE_EXPORT std::string StringPrintf(_Printf_format_string_ const char* format,
-                                     ...)
+BASE_EXPORT std::string StringPrintf(const char* format, ...)
     PRINTF_FORMAT(1, 2) WARN_UNUSED_RESULT;
 #if defined(OS_WIN)
-BASE_EXPORT std::wstring StringPrintf(
-    _Printf_format_string_ const wchar_t* format,
-    ...) WPRINTF_FORMAT(1, 2) WARN_UNUSED_RESULT;
+BASE_EXPORT std::wstring StringPrintf(const wchar_t* format, ...)
+    WPRINTF_FORMAT(1, 2) WARN_UNUSED_RESULT;
 #endif
 
 // Return a C++ string given vprintf-like input.
@@ -30,25 +28,21 @@ BASE_EXPORT std::string StringPrintV(const char* format, va_list ap)
     PRINTF_FORMAT(1, 0) WARN_UNUSED_RESULT;
 
 // Store result into a supplied string and return it.
-BASE_EXPORT const std::string& SStringPrintf(
-    std::string* dst,
-    _Printf_format_string_ const char* format,
-    ...) PRINTF_FORMAT(2, 3);
+BASE_EXPORT const std::string& SStringPrintf(std::string* dst,
+                                             const char* format,
+                                             ...) PRINTF_FORMAT(2, 3);
 #if defined(OS_WIN)
-BASE_EXPORT const std::wstring& SStringPrintf(
-    std::wstring* dst,
-    _Printf_format_string_ const wchar_t* format,
-    ...) WPRINTF_FORMAT(2, 3);
+BASE_EXPORT const std::wstring& SStringPrintf(std::wstring* dst,
+                                              const wchar_t* format,
+                                              ...) WPRINTF_FORMAT(2, 3);
 #endif
 
 // Append result to a supplied string.
-BASE_EXPORT void StringAppendF(std::string* dst,
-                               _Printf_format_string_ const char* format,
-                               ...) PRINTF_FORMAT(2, 3);
+BASE_EXPORT void StringAppendF(std::string* dst, const char* format, ...)
+    PRINTF_FORMAT(2, 3);
 #if defined(OS_WIN)
-BASE_EXPORT void StringAppendF(std::wstring* dst,
-                               _Printf_format_string_ const wchar_t* format,
-                               ...) WPRINTF_FORMAT(2, 3);
+BASE_EXPORT void StringAppendF(std::wstring* dst, const wchar_t* format, ...)
+    WPRINTF_FORMAT(2, 3);
 #endif
 
 // Lower-level routine that takes a va_list and appends to a specified
@@ -57,8 +51,8 @@ BASE_EXPORT void StringAppendV(std::string* dst, const char* format, va_list ap)
     PRINTF_FORMAT(2, 0);
 #if defined(OS_WIN)
 BASE_EXPORT void StringAppendV(std::wstring* dst,
-                               const wchar_t* format, va_list ap)
-    WPRINTF_FORMAT(2, 0);
+                               const wchar_t* format,
+                               va_list ap) WPRINTF_FORMAT(2, 0);
 #endif
 
 }  // namespace base

chrome/browser/sync_file_system/logger.h

@@ -24,7 +24,7 @@ void ClearLog();
 // This function can be called from any thread.
 void Log(logging::LogSeverity level,
          const base::Location& location,
-         _Printf_format_string_ const char* format,
+         const char* format,
          ...) PRINTF_FORMAT(3, 4);
 
 // Returns the log history.

components/drive/event_logger.h

@@ -46,9 +46,8 @@ class EventLogger {
 
   // Logs a message with formatting.
   // Can be called from any thread as long as the object is alive.
-  void Log(logging::LogSeverity severity,
-           _Printf_format_string_ const char* format,
-           ...) PRINTF_FORMAT(3, 4);
+  void Log(logging::LogSeverity severity, const char* format, ...)
+      PRINTF_FORMAT(3, 4);
 
   // Sets the history size. The existing history is cleared.
   // Can be called from any thread as long as the object is alive.