Add cmake option to disable minidumps, default it to off

Since crash dumping landed in r268519, May 2016, I have not once seen
anyone use an uploaded minidump to debug a compiler crash. Therefore,
I'm turning this off by default. The dumps clutter up user and buildbot
temp directories. Each file is only about 56KB, but it adds up.

In the context of clang, the extra line about the minidump confuses
users, when what we really want from them is the pre-processed source
code.

llvm-svn: 340185

llvm/CMakeLists.txt

@@ -320,6 +320,8 @@ if(LLVM_ENABLE_CRASH_OVERRIDES)
   set(ENABLE_CRASH_OVERRIDES 1)
 endif()
 
+option(LLVM_ENABLE_CRASH_DUMPS "Turn on memory dumps on crashes. Currently only implemented on Windows." OFF)
+
 option(LLVM_ENABLE_FFI "Use libffi to call external functions from the interpreter" OFF)
 set(FFI_LIBRARY_DIR "" CACHE PATH "Additional directory, where CMake should search for libffi.so")
 set(FFI_INCLUDE_DIR "" CACHE PATH "Additional directory, where CMake should search for ffi.h or ffi/ffi.h")

llvm/include/llvm/Config/config.h.cmake

@@ -13,6 +13,9 @@
 /* Define to 1 to enable crash overrides, and to 0 otherwise. */
 #cmakedefine01 ENABLE_CRASH_OVERRIDES
 
+/* Define to 1 to enable crash memory dumps, and to 0 otherwise. */
+#cmakedefine01 LLVM_ENABLE_CRASH_DUMPS
+
 /* Define to 1 if you have the `backtrace' function. */
 #cmakedefine HAVE_BACKTRACE ${HAVE_BACKTRACE}
 

llvm/lib/Support/Process.cpp

@@ -15,6 +15,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Config/llvm-config.h"
+#include "llvm/Config/config.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Program.h"
@@ -86,7 +87,7 @@ static const char colorcodes[2][2][8][10] = {
 static bool coreFilesPrevented = false;
 
 bool Process::AreCoreFilesPrevented() {
-  return coreFilesPrevented;
+  return !LLVM_ENABLE_CRASH_DUMPS;
 }
 
 // Include the platform-specific parts of this class.