Win: Add ANGLE_WAIT_FOR_DEBUGGER option.

src/libGL/libGL.rc

 // Microsoft Visual C++ generated resource script.
 //
-#include "resource.h"
+#include "../libGLESv2/resource.h"
 
 #define APSTUDIO_READONLY_SYMBOLS
 /////////////////////////////////////////////////////////////////////////////
@@ -87,6 +87,40 @@ BEGIN
     END
 END
 
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Dialog
+//
+
+IDD_DIALOG1 DIALOGEX 0, 0, 129, 47
+STYLE DS_SETFONT | DS_MODALFRAME | DS_FIXEDSYS | WS_POPUP | WS_CAPTION | WS_SYSMENU
+CAPTION "Waiting for debugger"
+FONT 8, "MS Shell Dlg", 400, 0, 0x1
+BEGIN
+PUSHBUTTON      "Cancel",IDCANCEL,72,26,50,14
+LTEXT           "Attach a debugger or ESC to cancel",IDC_STATIC,7,7,115,8
+END
+
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// DESIGNINFO
+//
+
+#ifdef APSTUDIO_INVOKED
+GUIDELINES DESIGNINFO
+BEGIN
+IDD_DIALOG1, DIALOG
+BEGIN
+LEFTMARGIN, 7
+RIGHTMARGIN, 122
+TOPMARGIN, 7
+BOTTOMMARGIN, 40
+END
+END
+#endif    // APSTUDIO_INVOKED
+
 #endif    // English (U.S.) resources
 /////////////////////////////////////////////////////////////////////////////
 

src/libGLESv2.gni

@@ -942,8 +942,6 @@ libangle_null_sources = [
 libgl_sources = [
   "src/common/angleutils.h",
   "src/common/debug.h",
-  "src/libGLESv2/global_state.cpp",
-  "src/libGLESv2/global_state.h",
   "src/libGL/entry_points_gl_1_0_autogen.cpp",
   "src/libGL/entry_points_gl_1_0_autogen.h",
   "src/libGL/entry_points_gl_1_1_autogen.cpp",
@@ -989,7 +987,9 @@ libgl_sources = [
   "src/libGL/libGL.rc",
   "src/libGL/proc_table_wgl.h",
   "src/libGL/proc_table_wgl_autogen.cpp",
-  "src/libGL/resource.h",
+  "src/libGLESv2/global_state.cpp",
+  "src/libGLESv2/global_state.h",
+  "src/libGLESv2/resource.h",
 ]
 
 libglesv2_sources = [

src/libGLESv2/global_state.cpp

@@ -10,7 +10,9 @@
 
 #include "common/debug.h"
 #include "common/platform.h"
+#include "common/system_utils.h"
 #include "common/tls.h"
+#include "libGLESv2/resource.h"
 
 namespace gl
 {
@@ -206,11 +208,67 @@ bool TerminateProcess()
 
 }  // namespace egl
 
-extern "C" BOOL WINAPI DllMain(HINSTANCE, DWORD reason, LPVOID)
+namespace
+{
+// The following WaitForDebugger code is based on SwiftShader. See:
+// https://cs.chromium.org/chromium/src/third_party/swiftshader/src/Vulkan/main.cpp
+#    if defined(ANGLE_ENABLE_ASSERTS)
+INT_PTR CALLBACK DebuggerWaitDialogProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+{
+    RECT rect;
+
+    switch (uMsg)
+    {
+        case WM_INITDIALOG:
+            ::GetWindowRect(GetDesktopWindow(), &rect);
+            ::SetWindowPos(hwnd, HWND_TOP, rect.right / 2, rect.bottom / 2, 0, 0, SWP_NOSIZE);
+            ::SetTimer(hwnd, 1, 100, NULL);
+            return TRUE;
+        case WM_COMMAND:
+            if (LOWORD(wParam) == IDCANCEL)
+            {
+                ::EndDialog(hwnd, 0);
+            }
+            break;
+        case WM_TIMER:
+            if (angle::IsDebuggerAttached())
+            {
+                ::EndDialog(hwnd, 0);
+            }
+    }
+
+    return FALSE;
+}
+
+void WaitForDebugger(HINSTANCE instance)
+{
+    if (angle::IsDebuggerAttached())
+        return;
+
+    HRSRC dialog = ::FindResourceA(instance, MAKEINTRESOURCEA(IDD_DIALOG1), MAKEINTRESOURCEA(5));
+    if (!dialog)
+    {
+        printf("Error finding wait for debugger dialog. Error %lu.\n", ::GetLastError());
+        return;
+    }
+
+    DLGTEMPLATE *dialogTemplate = reinterpret_cast<DLGTEMPLATE *>(::LoadResource(instance, dialog));
+    ::DialogBoxIndirectA(instance, dialogTemplate, NULL, DebuggerWaitDialogProc);
+}
+#    else
+void WaitForDebugger(HINSTANCE instance) {}
+#    endif  // defined(ANGLE_ENABLE_ASSERTS)
+}  // namespace
+
+extern "C" BOOL WINAPI DllMain(HINSTANCE instance, DWORD reason, LPVOID)
 {
     switch (reason)
     {
         case DLL_PROCESS_ATTACH:
+            if (angle::GetEnvironmentVar("ANGLE_WAIT_FOR_DEBUGGER") == "1")
+            {
+                WaitForDebugger(instance);
+            }
             return static_cast<BOOL>(egl::InitializeProcess());
 
         case DLL_THREAD_ATTACH:

src/libGLESv2/libGLESv2.rc

@@ -87,6 +87,40 @@ BEGIN
     END
 END
 
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Dialog
+//
+
+IDD_DIALOG1 DIALOGEX 0, 0, 129, 47
+STYLE DS_SETFONT | DS_MODALFRAME | DS_FIXEDSYS | WS_POPUP | WS_CAPTION | WS_SYSMENU
+CAPTION "Waiting for debugger"
+FONT 8, "MS Shell Dlg", 400, 0, 0x1
+BEGIN
+PUSHBUTTON      "Cancel",IDCANCEL,72,26,50,14
+LTEXT           "Attach a debugger or ESC to cancel",IDC_STATIC,7,7,115,8
+END
+
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// DESIGNINFO
+//
+
+#ifdef APSTUDIO_INVOKED
+GUIDELINES DESIGNINFO
+BEGIN
+IDD_DIALOG1, DIALOG
+BEGIN
+LEFTMARGIN, 7
+RIGHTMARGIN, 122
+TOPMARGIN, 7
+BOTTOMMARGIN, 40
+END
+END
+#endif    // APSTUDIO_INVOKED
+
 #endif    // English (U.S.) resources
 /////////////////////////////////////////////////////////////////////////////
 

src/libGLESv2/resource.h

@@ -2,6 +2,9 @@
 // Microsoft Visual C++ generated include file.
 // Used by libGLESv2.rc
 
+#define IDD_DIALOG1 101
+#define IDC_STATIC -1
+
 // Next default values for new objects
 //
 #ifdef APSTUDIO_INVOKED