Re: [PING2] : [RFC/RFA] PING: skip __main

Mark Kettenis
2008-05-30T12:00:34Z

> From: "Pierre Muller" <muller@ics.u-strasbg.fr>
> Date: Fri, 30 May 2008 13:18:20 +0200
>
> Hi, is there any chance that someone will have
> the time to review this patch?

I'm afraid I think that skip_main_constructor_call is too long as a name.

I'd also appreciate it if you could seperate local variable
declarations from the stations that follow by a blank line. Otherwise
this looks ok to me.

> -----Message d'origine-----
> DeÂ : gdb-patches-owner@sourceware.org
> [mailto:gdb-patches-owner@sourceware.org] De la part de Pierre Muller
> EnvoyÃ©Â : Friday, May 02, 2008 3:26 PM
> Ã€Â : 'Pedro Alves'; 'Daniel Jacobowitz'; gdb-patches@sourceware.org
> CcÂ : 'Mark Kettenis'
> ObjetÂ : [RFC/RFA] PING: skip __main
>
> Pedro submitted this patch end of January,
> but the 6.8 release pushed it to a later date.
> http://sourceware.org/ml/gdb-patches/2008-01/msg00665.html
>
> Now that GDB 6.8 is out,
> I would really like to get this patch in.
> Pedro, this is your work, but you seem to be
> much more involved in other things lately,
> thus, if you don't mind, I can try to push this through.
>
> I updated the patch from the first message
> referenced and just followed Daniel's advice in
> http://sourceware.org/ml/gdb-patches/2008-01/msg00883.html
> to change skip___main into skip_main_constructor.
>
> This __main call seems to be
> a common feature for coff format, thus
> I suppose that it applies to other targets,
> go32v2 djgpp is probably one of them.
>
> For cygwin target, I get this:
>
> === gdb Summary ===
>
> -# of expected passes 10733
> -# of unexpected failures 560
> +# of expected passes 10928
> +# of unexpected failures 363
> # of expected failures 59
> # of unknown successes 2
> -# of known failures 21
> +# of known failures 23
> # of unresolved testcases 40
> # of untested testcases 14
> # of unsupported tests 23
>
> Almost 200 failures less...
>
> Daniel wanted to get a comment from Mark
> in his last email in that thread, that is the reason
> why I added Mark Kettenis to the list of recipients.
>
> Does this patch look OK now?
>
> One point that should still be discussed is
> if we should call main_name function
> rather than hardcoded "main" in find_function_start_sal in symtab.c.
>
> Pierre Muller
> Pascal language support maintainer for GDB
>
>
> 2008-05-02 Pedro Alves <pedro_alves@portugalmail.pt>
> Pierre Muller <muller@ics.u-strasbg.fr>
>
> * gdbarch.sh (gdbarch_skip_main_constructor_call): New.
> * gdbarch.h, gdbarch.c: Regenerate.
>
> * i386-tdep.h (i386_skip_main_constructor_call): Declare.
> * i386-tdep.c (i386_skip_main_constructor_call): New.
> * i386-cygwin-tdep.c (i386_cygwin_init_abi): Register
> i386_skip_main_constructor_call as
> gdbarch_skip_main_constructor_call
> gdbarch callback.
> * symtab.c (find_function_start_sal): When pc points at the "main"
> function, call gdbarch_skip_main_constructor_call.
>
> Index: gdb/gdbarch.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/gdbarch.c,v
> retrieving revision 1.422
> diff -u -p -r1.422 gdbarch.c
> --- gdb/gdbarch.c 22 Apr 2008 11:03:41 -0000 1.422
> +++ gdb/gdbarch.c 30 Apr 2008 13:01:33 -0000
> @@ -184,6 +184,7 @@ struct gdbarch
> gdbarch_integer_to_address_ftype *integer_to_address;
> gdbarch_return_value_ftype *return_value;
> gdbarch_skip_prologue_ftype *skip_prologue;
> + gdbarch_skip_main_constructor_call_ftype *skip_main_constructor_call;
> gdbarch_inner_than_ftype *inner_than;
> gdbarch_breakpoint_from_pc_ftype *breakpoint_from_pc;
> gdbarch_adjust_breakpoint_address_ftype *adjust_breakpoint_address;
> @@ -306,6 +307,7 @@ struct gdbarch startup_gdbarch =
> 0, /* integer_to_address */
> 0, /* return_value */
> 0, /* skip_prologue */
> + 0, /* skip_main_constructor_call */
> 0, /* inner_than */
> 0, /* breakpoint_from_pc */
> 0, /* adjust_breakpoint_address */
> @@ -542,6 +544,7 @@ verify_gdbarch (struct gdbarch *gdbarch)
> /* Skip verify of return_value, has predicate */
> if (gdbarch->skip_prologue == 0)
> fprintf_unfiltered (log, "\n\tskip_prologue");
> + /* Skip verify of skip_main_constructor_call, has predicate */
> if (gdbarch->inner_than == 0)
> fprintf_unfiltered (log, "\n\tinner_than");
> if (gdbarch->breakpoint_from_pc == 0)
> @@ -934,6 +937,12 @@ gdbarch_dump (struct gdbarch *gdbarch, s
> "gdbarch_dump: single_step_through_delay =
> <0x%lx>\n",
> (long) gdbarch->single_step_through_delay);
> fprintf_unfiltered (file,
> + "gdbarch_dump: gdbarch_skip_main_constructor_call_p()
> = %d\n",
> + gdbarch_skip_main_constructor_call_p (gdbarch));
> + fprintf_unfiltered (file,
> + "gdbarch_dump: skip_main_constructor_call =
> <0x%lx>\n",
> + (long) gdbarch->skip_main_constructor_call);
> + fprintf_unfiltered (file,
> "gdbarch_dump: gdbarch_skip_permanent_breakpoint_p()
> = %d\n",
> gdbarch_skip_permanent_breakpoint_p (gdbarch));
> fprintf_unfiltered (file,
> @@ -2075,6 +2084,30 @@ set_gdbarch_skip_prologue (struct gdbarc
> }
>
> int
> +gdbarch_skip_main_constructor_call_p (struct gdbarch *gdbarch)
> +{
> + gdb_assert (gdbarch != NULL);
> + return gdbarch->skip_main_constructor_call != NULL;
> +}
> +
> +CORE_ADDR
> +gdbarch_skip_main_constructor_call (struct gdbarch *gdbarch, CORE_ADDR ip)
> +{
> + gdb_assert (gdbarch != NULL);
> + gdb_assert (gdbarch->skip_main_constructor_call != NULL);
> + if (gdbarch_debug >= 2)
> + fprintf_unfiltered (gdb_stdlog, "gdbarch_skip_main_constructor_call
> called\n");
> + return gdbarch->skip_main_constructor_call (gdbarch, ip);
> +}
> +
> +void
> +set_gdbarch_skip_main_constructor_call (struct gdbarch *gdbarch,
> + gdbarch_skip_main_constructor_call_ftype
> skip_main_constructor_call)
> +{
> + gdbarch->skip_main_constructor_call = skip_main_constructor_call;
> +}
> +
> +int
> gdbarch_inner_than (struct gdbarch *gdbarch, CORE_ADDR lhs, CORE_ADDR rhs)
> {
> gdb_assert (gdbarch != NULL);
> Index: gdb/gdbarch.h
> ===================================================================
> RCS file: /cvs/src/src/gdb/gdbarch.h,v
> retrieving revision 1.377
> diff -u -p -r1.377 gdbarch.h
> --- gdb/gdbarch.h 29 Apr 2008 16:06:07 -0000 1.377
> +++ gdb/gdbarch.h 30 Apr 2008 13:01:33 -0000
> @@ -381,6 +381,12 @@ typedef CORE_ADDR (gdbarch_skip_prologue
> extern CORE_ADDR gdbarch_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR
> ip);
> extern void set_gdbarch_skip_prologue (struct gdbarch *gdbarch,
> gdbarch_skip_prologue_ftype *skip_prologue);
>
> +extern int gdbarch_skip_main_constructor_call_p (struct gdbarch *gdbarch);
> +
> +typedef CORE_ADDR (gdbarch_skip_main_constructor_call_ftype) (struct
> gdbarch *gdbarch, CORE_ADDR ip);
> +extern CORE_ADDR gdbarch_skip_main_constructor_call (struct gdbarch
> *gdbarch, CORE_ADDR ip);
> +extern void set_gdbarch_skip_main_constructor_call (struct gdbarch
> *gdbarch, gdbarch_skip_main_constructor_call_ftype
> *skip_main_constructor_call);
> +
> typedef int (gdbarch_inner_than_ftype) (CORE_ADDR lhs, CORE_ADDR rhs);
> extern int gdbarch_inner_than (struct gdbarch *gdbarch, CORE_ADDR lhs,
> CORE_ADDR rhs);
> extern void set_gdbarch_inner_than (struct gdbarch *gdbarch,
> gdbarch_inner_than_ftype *inner_than);
> Index: gdb/gdbarch.sh
> ===================================================================
> RCS file: /cvs/src/src/gdb/gdbarch.sh,v
> retrieving revision 1.463
> diff -u -p -r1.463 gdbarch.sh
> --- gdb/gdbarch.sh 29 Apr 2008 16:06:06 -0000 1.463
> +++ gdb/gdbarch.sh 30 Apr 2008 13:01:34 -0000
> @@ -483,6 +483,7 @@ M:CORE_ADDR:integer_to_address:struct ty
> M:enum return_value_convention:return_value:struct type *functype, struct
> type *valtype, struct regcache *regcache, gdb_byte *readbuf, const gdb_byte
> *writebuf:functype, valtype, regcache, readbuf, writebuf
>
> m:CORE_ADDR:skip_prologue:CORE_ADDR ip:ip:0:0
> +M:CORE_ADDR:skip_main_constructor_call:CORE_ADDR ip:ip
> f:int:inner_than:CORE_ADDR lhs, CORE_ADDR rhs:lhs, rhs:0:0
> m:const gdb_byte *:breakpoint_from_pc:CORE_ADDR *pcptr, int *lenptr:pcptr,
> lenptr::0:
> M:CORE_ADDR:adjust_breakpoint_address:CORE_ADDR bpaddr:bpaddr
> Index: gdb/i386-cygwin-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/i386-cygwin-tdep.c,v
> retrieving revision 1.16
> diff -u -p -r1.16 i386-cygwin-tdep.c
> --- gdb/i386-cygwin-tdep.c 1 Jan 2008 22:53:10 -0000 1.16
> +++ gdb/i386-cygwin-tdep.c 30 Apr 2008 13:01:34 -0000
> @@ -227,6 +227,8 @@ i386_cygwin_init_abi (struct gdbarch_inf
>
> set_gdbarch_skip_trampoline_code (gdbarch,
> i386_cygwin_skip_trampoline_code);
>
> + set_gdbarch_skip_main_constructor_call (gdbarch,
> i386_skip_main_constructor_call);
> +
> tdep->struct_return = reg_struct_return;
>
> tdep->gregset_reg_offset = i386_win32_gregset_reg_offset;
> Index: gdb/i386-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/i386-tdep.c,v
> retrieving revision 1.255
> diff -u -p -r1.255 i386-tdep.c
> --- gdb/i386-tdep.c 25 Apr 2008 14:57:30 -0000 1.255
> +++ gdb/i386-tdep.c 30 Apr 2008 13:01:35 -0000
> @@ -941,6 +941,33 @@ i386_skip_prologue (struct gdbarch *gdba
> return pc;
> }
>
> +/* Check that the code pointed to by PC corresponds to a call to
> + __main, skip it if so. Return PC otherwise. */
> +
> +CORE_ADDR
> +i386_skip_main_constructor_call (struct gdbarch *gdbarch, CORE_ADDR pc)
> +{
> + gdb_byte op;
> +
> + target_read_memory (pc, &op, 1);
> + if (op == 0xe8)
> + {
> + gdb_byte buf[4];
> + if (target_read_memory (pc + 1, buf, sizeof buf) == 0)
> + {
> + CORE_ADDR call_dest = pc + 5 + extract_unsigned_integer (buf, 4);
> +
> + struct minimal_symbol *s = lookup_minimal_symbol_by_pc
> (call_dest);
> + if (s != NULL
> + && SYMBOL_LINKAGE_NAME (s) != NULL
> + && strcmp (SYMBOL_LINKAGE_NAME (s), "__main") == 0)
> + pc += 5;
> + }
> + }
> +
> + return pc;
> +}
> +
> /* This function is 64-bit safe. */
>
> static CORE_ADDR
> Index: gdb/i386-tdep.h
> ===================================================================
> RCS file: /cvs/src/src/gdb/i386-tdep.h,v
> retrieving revision 1.53
> diff -u -p -r1.53 i386-tdep.h
> --- gdb/i386-tdep.h 11 Mar 2008 05:21:38 -0000 1.53
> +++ gdb/i386-tdep.h 30 Apr 2008 13:01:35 -0000
> @@ -166,6 +166,7 @@ extern struct type *i386_sse_type (struc
>
> /* Functions exported from i386-tdep.c. */
> extern CORE_ADDR i386_pe_skip_trampoline_code (CORE_ADDR pc, char *name);
> +extern CORE_ADDR i386_skip_main_constructor_call (struct gdbarch *gdbarch,
> CORE_ADDR pc);
>
> /* Return the name of register REGNUM. */
> extern char const *i386_register_name (struct gdbarch * gdbarch, int
> regnum);
> Index: gdb/symtab.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/symtab.c,v
> retrieving revision 1.177
> diff -u -p -r1.177 symtab.c
> --- gdb/symtab.c 19 Apr 2008 11:39:50 -0000 1.177
> +++ gdb/symtab.c 30 Apr 2008 13:01:36 -0000
> @@ -2572,6 +2572,21 @@ find_function_start_sal (struct symbol *
> /* Recalculate the line number (might not be N+1). */
> sal = find_pc_sect_line (pc, SYMBOL_BFD_SECTION (sym), 0);
> }
> +
> + /* On targets with executable formats that don't have a concept of
> + constructors (ELF with .init has, PE doesn't), gcc emits a call
> + to `__main' in `main' between the prologue and before user
> + code. */
> + if (funfirstline
> + && gdbarch_skip_main_constructor_call_p (current_gdbarch)
> + && SYMBOL_LINKAGE_NAME (sym)
> + && strcmp (SYMBOL_LINKAGE_NAME (sym), "main") == 0)
> + {
> + pc = gdbarch_skip_main_constructor_call (current_gdbarch, pc);
> + /* Recalculate the line number (might not be N+1). */
> + sal = find_pc_sect_line (pc, SYMBOL_BFD_SECTION (sym), 0);
> + }
> +
> sal.pc = pc;
>
> return sal;
>
>
>
>
>
>