Implement debugging of WOW64 processes in gdbserver

gdbserver/ChangeLog:

2020-04-30  Hannes Domani  <ssbssa@yahoo.de>

	* configure.srv <x86_64-*-mingw*, x86_64-*-cygwin*> (srv_tgtobj):
	Add arch/i386.o.
	* win32-arm-low.cc (arm_num_regs): New function.
	(struct win32_target_ops): Use arm_num_regs.
	* win32-i386-low.cc (win32_get_current_dr): Adapt for WOW64
	processes.
	(i386_get_thread_context): Likewise.
	(i386_prepare_to_resume): Likewise.
	(i386_thread_added): Likewise.
	(i386_single_step): Likewise.
	(i386_fetch_inferior_register): Likewise.
	(i386_store_inferior_register): Likewise.
	(i386_arch_setup): Likewise.
	(i386_win32_num_regs): New function.
	(struct win32_target_ops): Use i386_win32_num_regs.
	* win32-low.cc (win32_get_thread_context): Adapt for WOW64
	processes.
	(win32_require_context): Likewise.
	(child_add_thread): Likewise.
	(do_initial_child_stuff): Likewise.
	(continue_one_thread): Likewise.
	(win32_process_target::resume): Likewise.
	(load_psapi): Likewise.
	(win32_add_all_dlls): Likewise.
	(maybe_adjust_pc): Likewise.
	(win32_process_target::qxfer_siginfo): Likewise.
	(initialize_low): Likewise.
	* win32-low.h (struct win32_target_ops): Change num_regs to
	callback function.

1 files changed, 138 insertions, 33 deletions

diff --git a/gdbserver/win32-i386-low.cc b/gdbserver/win32-i386-low.cc
index 48893af..389ec49 100644
--- a/gdbserver/win32-i386-low.cc
+++ b/gdbserver/win32-i386-low.cc
@@ -80,18 +80,40 @@ win32_get_current_dr (int dr)
 
   win32_require_context (th);
 
+#ifdef __x86_64__
+#define RET_DR(DR)				\
+  case DR:					\
+    return th->wow64_context.Dr ## DR
+
+  if (wow64_process)
+    {
+      switch (dr)
+	{
+	  RET_DR (0);
+	  RET_DR (1);
+	  RET_DR (2);
+	  RET_DR (3);
+	  RET_DR (6);
+	  RET_DR (7);
+	}
+    }
+  else
+#undef RET_DR
+#endif
 #define RET_DR(DR)				\
   case DR:					\
     return th->context.Dr ## DR
 
-  switch (dr)
     {
-      RET_DR (0);
-      RET_DR (1);
-      RET_DR (2);
-      RET_DR (3);
-      RET_DR (6);
-      RET_DR (7);
+      switch (dr)
+	{
+	  RET_DR (0);
+	  RET_DR (1);
+	  RET_DR (2);
+	  RET_DR (3);
+	  RET_DR (6);
+	  RET_DR (7);
+	}
     }
 
 #undef RET_DR
@@ -219,12 +241,27 @@ i386_get_thread_context (windows_thread_info *th)
   static DWORD extended_registers = CONTEXT_EXTENDED_REGISTERS;
 
  again:
-  th->context.ContextFlags = (CONTEXT_FULL
-			      | CONTEXT_FLOATING_POINT
-			      | CONTEXT_DEBUG_REGISTERS
-			      | extended_registers);
+#ifdef __x86_64__
+  if (wow64_process)
+    th->wow64_context.ContextFlags = (CONTEXT_FULL
+				      | CONTEXT_FLOATING_POINT
+				      | CONTEXT_DEBUG_REGISTERS
+				      | extended_registers);
+  else
+#endif
+    th->context.ContextFlags = (CONTEXT_FULL
+				| CONTEXT_FLOATING_POINT
+				| CONTEXT_DEBUG_REGISTERS
+				| extended_registers);
 
-  if (!GetThreadContext (th->h, &th->context))
+  BOOL ret;
+#ifdef __x86_64__
+  if (wow64_process)
+    ret = win32_Wow64GetThreadContext (th->h, &th->wow64_context);
+  else
+#endif
+    ret = GetThreadContext (th->h, &th->context);
+  if (!ret)
     {
       DWORD e = GetLastError ();
 
@@ -247,13 +284,28 @@ i386_prepare_to_resume (windows_thread_info *th)
 
       win32_require_context (th);
 
-      th->context.Dr0 = dr->dr_mirror[0];
-      th->context.Dr1 = dr->dr_mirror[1];
-      th->context.Dr2 = dr->dr_mirror[2];
-      th->context.Dr3 = dr->dr_mirror[3];
-      /* th->context.Dr6 = dr->dr_status_mirror;
-	 FIXME: should we set dr6 also ?? */
-      th->context.Dr7 = dr->dr_control_mirror;
+#ifdef __x86_64__
+      if (wow64_process)
+	{
+	  th->wow64_context.Dr0 = dr->dr_mirror[0];
+	  th->wow64_context.Dr1 = dr->dr_mirror[1];
+	  th->wow64_context.Dr2 = dr->dr_mirror[2];
+	  th->wow64_context.Dr3 = dr->dr_mirror[3];
+	  /* th->wow64_context.Dr6 = dr->dr_status_mirror;
+	     FIXME: should we set dr6 also ?? */
+	  th->wow64_context.Dr7 = dr->dr_control_mirror;
+	}
+      else
+#endif
+	{
+	  th->context.Dr0 = dr->dr_mirror[0];
+	  th->context.Dr1 = dr->dr_mirror[1];
+	  th->context.Dr2 = dr->dr_mirror[2];
+	  th->context.Dr3 = dr->dr_mirror[3];
+	  /* th->context.Dr6 = dr->dr_status_mirror;
+	     FIXME: should we set dr6 also ?? */
+	  th->context.Dr7 = dr->dr_control_mirror;
+	}
 
       th->debug_registers_changed = false;
     }
@@ -268,11 +320,14 @@ i386_thread_added (windows_thread_info *th)
 static void
 i386_single_step (windows_thread_info *th)
 {
-  th->context.EFlags |= FLAG_TRACE_BIT;
+#ifdef __x86_64__
+  if (wow64_process)
+    th->wow64_context.EFlags |= FLAG_TRACE_BIT;
+  else
+#endif
+    th->context.EFlags |= FLAG_TRACE_BIT;
 }
 
-#ifndef __x86_64__
-
 /* An array of offset mappings into a Win32 Context structure.
    This is a one-to-one mapping which is indexed by gdb's register
    numbers.  It retrieves an offset into the context structure where
@@ -280,8 +335,12 @@ i386_single_step (windows_thread_info *th)
    An offset value of -1 indicates that Win32 does not provide this
    register in it's CONTEXT structure.  In this case regptr will return
    a pointer into a dummy register.  */
+#ifdef __x86_64__
+#define context_offset(x) (offsetof (WOW64_CONTEXT, x))
+#else
 #define context_offset(x) ((int)&(((CONTEXT *)NULL)->x))
-static const int mappings[] = {
+#endif
+static const int i386_mappings[] = {
   context_offset (Eax),
   context_offset (Ecx),
   context_offset (Edx),
@@ -328,10 +387,10 @@ static const int mappings[] = {
 };
 #undef context_offset
 
-#else /* __x86_64__ */
+#ifdef __x86_64__
 
 #define context_offset(x) (offsetof (CONTEXT, x))
-static const int mappings[] =
+static const int amd64_mappings[] =
 {
   context_offset (Rax),
   context_offset (Rbx),
@@ -402,7 +461,21 @@ static void
 i386_fetch_inferior_register (struct regcache *regcache,
 			      windows_thread_info *th, int r)
 {
-  char *context_offset = (char *) &th->context + mappings[r];
+  const int *mappings;
+#ifdef __x86_64__
+  if (!wow64_process)
+    mappings = amd64_mappings;
+  else
+#endif
+    mappings = i386_mappings;
+
+  char *context_offset;
+#ifdef __x86_64__
+  if (wow64_process)
+    context_offset = (char *) &th->wow64_context + mappings[r];
+  else
+#endif
+    context_offset = (char *) &th->context + mappings[r];
 
   long l;
   if (r == FCS_REGNUM)
@@ -424,7 +497,22 @@ static void
 i386_store_inferior_register (struct regcache *regcache,
 			      windows_thread_info *th, int r)
 {
-  char *context_offset = (char *) &th->context + mappings[r];
+  const int *mappings;
+#ifdef __x86_64__
+  if (!wow64_process)
+    mappings = amd64_mappings;
+  else
+#endif
+    mappings = i386_mappings;
+
+  char *context_offset;
+#ifdef __x86_64__
+  if (wow64_process)
+    context_offset = (char *) &th->wow64_context + mappings[r];
+  else
+#endif
+    context_offset = (char *) &th->context + mappings[r];
+
   collect_register (regcache, r, context_offset);
 }
 
@@ -439,15 +527,32 @@ i386_arch_setup (void)
 #ifdef __x86_64__
   tdesc = amd64_create_target_description (X86_XSTATE_SSE_MASK, false,
 					   false, false);
-  const char **expedite_regs = amd64_expedite_regs;
-#else
+  init_target_desc (tdesc, amd64_expedite_regs);
+  win32_tdesc = tdesc;
+#endif
+
   tdesc = i386_create_target_description (X86_XSTATE_SSE_MASK, false, false);
-  const char **expedite_regs = i386_expedite_regs;
+  init_target_desc (tdesc, i386_expedite_regs);
+#ifdef __x86_64__
+  wow64_win32_tdesc = tdesc;
+#else
+  win32_tdesc = tdesc;
 #endif
+}
 
-  init_target_desc (tdesc, expedite_regs);
+/* Implement win32_target_ops "num_regs" method.  */
 
-  win32_tdesc = tdesc;
+static int
+i386_win32_num_regs (void)
+{
+  int num_regs;
+#ifdef __x86_64__
+  if (!wow64_process)
+    num_regs = sizeof (amd64_mappings) / sizeof (amd64_mappings[0]);
+  else
+#endif
+    num_regs = sizeof (i386_mappings) / sizeof (i386_mappings[0]);
+  return num_regs;
 }
 
 /* Implement win32_target_ops "get_pc" method.  */
@@ -496,7 +601,7 @@ i386_win32_set_pc (struct regcache *regcache, CORE_ADDR pc)
 
 struct win32_target_ops the_low_target = {
   i386_arch_setup,
-  sizeof (mappings) / sizeof (mappings[0]),
+  i386_win32_num_regs,
   i386_initial_stuff,
   i386_get_thread_context,
   i386_prepare_to_resume,