Add Clang static analyzer to Clang toolchain defs in GN

base/logging.h

Index: base/logging.h
diff --git a/base/logging.h b/base/logging.h
index 7854e3934e974b4670930d6855f3ab8699a8376f..07e2a02e2d256a7027f6cf84614cea323eae2f5f 100644
--- a/base/logging.h
+++ b/base/logging.h
@@ -726,7 +726,27 @@ const LogSeverity LOG_DCHECK = LOG_INFO;
   LAZY_STREAM(PLOG_STREAM(DCHECK), false)                               \
   << "Check failed: " #condition ". "
 
-#else  // _PREFAST_
+#elif defined(__clang_analyzer__)
+
+// Keeps the static analyzer from proceeding along the current codepath,
+// otherwise false positive errors may be generated  by null pointer checks.

[Nico, 2017/01/11 20:20:05]

this is getting reviewed separately, right?

[Wez, 2017/01/14 00:04:58]

Rather than have duplicate D[P]CHECK definitions, could we instead define e.g. a
LOGGING_NORETURN(command) macro that depends on __clang_analyzer__, to keep the
analyzer changes more localized? i.e.:

#if __clang_analyzer__
#define LOGGING_NORETURN(command) (AnalyzerNoReturn(), command)
#else
#define LOGGING_NORETURN(command) command
#endif

[Kevin M, 2017/01/18 23:04:23]

Yeah, I had patched it in to verify that it is WAI. upstream-branch was giving
me errors on git-cl upload so the changes on that CL got into this diff too.
I'll remove the patch.

[Kevin M, 2017/01/18 23:04:23]

Will address this in the other CL.

+inline constexpr bool AnalyzerNoReturn() __attribute__((analyzer_noreturn)) {
+  return false;
+}
+
+#define DCHECK(condition)                                                   \
+  LAZY_STREAM(                                                              \
+      LOG_STREAM(DCHECK),                                                   \
+      DCHECK_IS_ON() ? (logging::AnalyzerNoReturn(), !(condition)) : false) \
+      << "Check failed: " #condition ". "
+
+#define DPCHECK(condition)                                                  \
+  LAZY_STREAM(                                                              \
+      PLOG_STREAM(DCHECK),                                                  \
+      DCHECK_IS_ON() ? (logging::AnalyzerNoReturn(), !(condition)) : false) \
+      << "Check failed: " #condition ". "
+
+#else
 
 #define DCHECK(condition)                                                \
   LAZY_STREAM(LOG_STREAM(DCHECK), DCHECK_IS_ON() ? !(condition) : false) \
@@ -736,7 +756,7 @@ const LogSeverity LOG_DCHECK = LOG_INFO;
   LAZY_STREAM(PLOG_STREAM(DCHECK), DCHECK_IS_ON() ? !(condition) : false) \
       << "Check failed: " #condition ". "
 
-#endif  // _PREFAST_
+#endif
 
 // Helper macro for binary operators.
 // Don't use this macro directly in your code, use DCHECK_EQ et al below.