Break debugger on assertion failure.

src/common/debug.cpp

@@ -23,6 +23,7 @@
 
 #include "common/Optional.h"
 #include "common/angleutils.h"
+#include "common/system_utils.h"
 
 namespace gl
 {
@@ -168,7 +169,14 @@ LogMessage::~LogMessage()
 
     if (mSeverity == LOG_FATAL)
     {
-        ANGLE_CRASH();
+        if (angle::IsDebuggerAttached())
+        {
+            angle::BreakDebugger();
+        }
+        else
+        {
+            ANGLE_CRASH();
+        }
     }
 }
 

src/common/system_utils.h

@@ -52,6 +52,12 @@ class Library : angle::NonCopyable
 };
 
 Library *OpenSharedLibrary(const char *libraryName);
+
+// Returns true if the process is currently being debugged.
+bool IsDebuggerAttached();
+
+// Calls system APIs to break into the debugger.
+void BreakDebugger();
 }  // namespace angle
 
 #endif  // COMMON_SYSTEM_UTILS_H_

src/common/system_utils_posix.cpp

@@ -263,4 +263,18 @@ bool IsDirectory(const char *filename)
     int result = stat(filename, &st);
     return result == 0 && ((st.st_mode & S_IFDIR) == S_IFDIR);
 }
+
+bool IsDebuggerAttached()
+{
+    // This could have a fuller implementation.
+    // See https://cs.chromium.org/chromium/src/base/debug/debugger_posix.cc
+    return false;
+}
+
+void BreakDebugger()
+{
+    // This could have a fuller implementation.
+    // See https://cs.chromium.org/chromium/src/base/debug/debugger_posix.cc
+    abort();
+}
 }  // namespace angle

src/common/system_utils_win.cpp

@@ -297,4 +297,14 @@ bool IsDirectory(const char *filename)
 
     return false;
 }
+
+bool IsDebuggerAttached()
+{
+    return !!::IsDebuggerPresent();
+}
+
+void BreakDebugger()
+{
+    __debugbreak();
+}
 }  // namespace angle