Change DumpProcessWithoutCrash to use load-time dynamic linking

chrome/app/chrome_main.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdint.h>
 
 #include "base/command_line.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "chrome/app/chrome_main_delegate.h"
@@ skipping 15 matching lines @@
 #if defined(OS_MACOSX)
 #include "chrome/app/chrome_main_mac.h"
 #endif
 
 #if defined(OS_WIN)
 #include "base/debug/dump_without_crashing.h"
 #include "base/win/win_util.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/install_static/initialize_from_primary_module.h"
 #include "chrome/install_static/install_details.h"
+#include "chrome_elf/chrome_elf_main.h"
 
 #define DLLEXPORT __declspec(dllexport)
 
 // We use extern C for the prototype DLLEXPORT to avoid C++ name mangling.
 extern "C" {
 DLLEXPORT int __cdecl ChromeMain(HINSTANCE instance,
                                  sandbox::SandboxInterfaceInfo* sandbox_info,
                                  int64_t exe_entry_point_ticks);
 }
 #elif defined(OS_POSIX)
@@ skipping 20 matching lines @@
       base::TimeTicks::FromInternalValue(exe_entry_point_ticks));
   content::ContentMainParams params(&chrome_main_delegate);
 
 #if defined(OS_WIN)
   // The process should crash when going through abnormal termination.
   base::win::SetShouldCrashOnProcessDetach(true);
   base::win::SetAbortBehaviorForCrashReporting();
   params.instance = instance;
   params.sandbox_info = sandbox_info;
 
-  // SetDumpWithoutCrashingFunction must be passed the DumpProcess function
-  // from chrome_elf and not from the DLL in order for DumpWithoutCrashing to
-  // function correctly.
-  typedef void (__cdecl *DumpProcessFunction)();
-  DumpProcessFunction DumpProcess = reinterpret_cast<DumpProcessFunction>(
-      ::GetProcAddress(::GetModuleHandle(chrome::kChromeElfDllName),
-                       "DumpProcessWithoutCrash"));
-  CHECK(DumpProcess);
-  base::debug::SetDumpWithoutCrashingFunction(DumpProcess);
+  base::debug::SetDumpWithoutCrashingFunction(GetDumpWithoutCrashingFunction());

[scottmg, 2017/06/15 23:08:47]

Why does this have to be a function that returns a function, can't it just be a
function that we reference instead?

[Will Harris, 2017/06/15 23:37:24]

base can't call out of base, which is why we pass the function into base using
SetDumpWithoutCrashingFunction.

we have to set the crash function in the right copy of base, there's one linked
with each executable. This sets the crash function for chrome.exe which is why
it's in chromemain.

Hope that makes sense.

[scottmg, 2017/06/16 00:26:24]

But couldn't it just be 

  base::debug::SetDumpWithoutCrashingFunction(&DumpWithoutCrashingFunction);

?

[Will Harris, 2017/06/16 00:37:48]

maybe - but &DumpWithoutCrashingFunction would be in chrome_elf wouldn't it,
assuming the linker will still like this?

[Will Harris, 2017/06/21 14:31:26]

this is done, and verified that it calls down to the chrome_elf version for both
main exe and dll.

 
   // Verify that chrome_elf and this module (chrome.dll and chrome_child.dll)
   // have the same version.
   if (install_static::InstallDetails::Get().VersionMismatch())
     base::debug::DumpWithoutCrashing();
 #else
   params.argc = argc;
   params.argv = argv;
   base::CommandLine::Init(params.argc, params.argv);
 #endif  // defined(OS_WIN)
@@ skipping 22 matching lines @@
 #endif  // BUILDFLAG(ENABLE_PACKAGE_MASH_SERVICES)
 
   int rv = content::ContentMain(params);
 
 #if defined(OS_WIN)
   base::win::SetShouldCrashOnProcessDetach(false);
 #endif
 
   return rv;
 }