This is the mail archive of the
gdb-patches@sourceware.org
mailing list for the GDB project.
arm-wince, skip call to __gccmain in main.
- From: Pedro Alves <pedro at codesourcery dot com>
- To: gdb-patches at sourceware dot org
- Date: Sun, 5 Jul 2009 22:30:13 +0100
- Subject: arm-wince, skip call to __gccmain in main.
This patch makes GDB skip the __gccmain call gcc places on `main'
(to run global C++ contructors), when analysing main's prologue.
The end result is that gdb places a breakpoint at the first line
of user code instead of at the main's opening '{' --- this shaves
off a few hundred testsuite failures.
I've had this here for a long, long while... It's checked in now.
--
Pedro Alves
2009-07-05 Pedro Alves <pedro@codesourcery.com>
* arm-wince-tdep.c (arm_wince_skip_main_prologue): New.
(arm_wince_init_abi): Register it as gdbarch_skip_main_prologue
callback.
---
gdb/arm-wince-tdep.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
Index: src/gdb/arm-wince-tdep.c
===================================================================
--- src.orig/gdb/arm-wince-tdep.c 2009-07-05 22:18:16.000000000 +0100
+++ src/gdb/arm-wince-tdep.c 2009-07-05 22:22:58.000000000 +0100
@@ -77,6 +77,40 @@ arm_pe_skip_trampoline_code (struct fram
return arm_skip_stub (frame, pc);
}
+/* GCC emits a call to __gccmain in the prologue of main.
+
+ The function below examines the code pointed at by PC and checks to
+ see if it corresponds to a call to __gccmain. If so, it returns
+ the address of the instruction following that call. Otherwise, it
+ simply returns PC. */
+
+CORE_ADDR
+arm_wince_skip_main_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
+{
+ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+ ULONGEST this_instr;
+
+ this_instr = read_memory_unsigned_integer (pc, 4, byte_order);
+
+ /* bl offset <__gccmain> */
+ if ((this_instr & 0xfff00000) == 0xeb000000)
+ {
+#define sign_extend(V, N) \
+ (((long) (V) ^ (1L << ((N) - 1))) - (1L << ((N) - 1)))
+
+ long offset = sign_extend (this_instr & 0x000fffff, 23) << 2;
+ CORE_ADDR call_dest = (pc + 8 + offset) & 0xffffffffU;
+ struct minimal_symbol *s = lookup_minimal_symbol_by_pc (call_dest);
+
+ if (s != NULL
+ && SYMBOL_LINKAGE_NAME (s) != NULL
+ && strcmp (SYMBOL_LINKAGE_NAME (s), "__gccmain") == 0)
+ pc += 4;
+ }
+
+ return pc;
+}
+
static void
arm_wince_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
@@ -102,6 +136,9 @@ arm_wince_init_abi (struct gdbarch_info
/* Single stepping. */
set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
+
+ /* Skip call to __gccmain that gcc places in main. */
+ set_gdbarch_skip_main_prologue (gdbarch, arm_wince_skip_main_prologue);
}
static enum gdb_osabi
--
Pedro Alves