[PATCH v4] Add dll trampoline code handling for windows 64bit

Roland Schwingel
2012-04-02T14:54:25Z

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Hi,

Pedro Alves wrote on 30.03.2012 11:14:03:

> Please send an updated patch, so we have in the archives the exact
> patch as what is
> checked in, and in case some other maintainer wants to take a look,
> best have him look at
> the refreshed patch. In fact, if you had sent it already in that
> email, there'd have been
> no extra noise, right? ;-)
Regarding the noise right. But not regarding generating additional work.
But ok... Here is now generation 4 of my patch. It incorporates all
formatting wishes of Joel.

I am still waiting for my copyright assignment stuff to be processed. It
is now more than 2 weeks. What is the official way to ping it?

ChangeLog:

2012-04-02 Roland Schwingel <roland.schwingel@onevision.com>

* amd64-windows-tdep.c: #include "frame.h".
(amd64_windows_skip_trampoline_code): New function.
(amd64_windows_init_abi): Add trampoline registration.

Thanks,

Roland

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--- amd64-windows-tdep.c.orig 2012-03-02 01:06:12.000000000 +0100
+++ amd64-windows-tdep.c 2012-03-30 13:03:23.944573800 +0200
@@ -23,6 +23,7 @@
#include "gdbtypes.h"
#include "gdbcore.h"
#include "regcache.h"
+#include "frame.h"

/* The registers used to pass integer arguments during a function call. */
static int amd64_windows_dummy_call_integer_regs[] =
@@ -153,12 +154,49 @@
return pc;
}

+/* Check win64 DLL jmp trampolines and find jump destination. */
+
+static CORE_ADDR
+amd64_windows_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
+{
+ CORE_ADDR destination = 0;
+ struct gdbarch *gdbarch = get_frame_arch (frame);
+ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+
+ /* Check for jmp *<offset>(%rip) (jump near, absolute indirect (/4)). */
+ if (pc && read_memory_unsigned_integer (pc, 2, byte_order) == 0x25ff)
+ {
+ /* Get opcode offset and see if we can find a reference in our data. */
+ ULONGEST offset =
+ read_memory_unsigned_integer (pc + 2, 4, byte_order);
+
+ /* Get address of function pointer at end of pc. */
+ CORE_ADDR indirect_addr = pc + offset + 6;
+
+ struct minimal_symbol *indsym =
+ indirect_addr ? lookup_minimal_symbol_by_pc (indirect_addr) : NULL;
+ const char *symname = indsym ? SYMBOL_LINKAGE_NAME (indsym) : NULL;
+
+ if (symname)
+ {
+ if (strncmp (symname, "__imp_", 6) == 0
+ || strncmp (symname, "_imp_", 5) == 0)
+ destination =
+ read_memory_unsigned_integer (indirect_addr, 8, byte_order);
+ }
+ }
+
+ return destination;
+}

static void
amd64_windows_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

+ /* Register trampoline handling code. */
+ set_gdbarch_skip_trampoline_code (gdbarch, amd64_windows_skip_trampoline_code);
+
amd64_init_abi (info, gdbarch);

/* On Windows, "long"s are only 32bit. */