[PATCH] [aarch64] Remove handling of ADR/ADRP from prologue analyzer

[PATCH] [aarch64] Remove handling of ADR/ADRP from prologue analyzer

[Luis Machado]

As reported by Tom in https://sourceware.org/pipermail/gdb-patches/2022-August/191357.html,
the aarch64 prologue analyzer considers the adrp instruction in the
gdb.dwarf2/dw2-dir-file-name.exp testcase to be part of a prologue.

The function has no prologue though, and it only loads the volatile variable
from memory.  GDB should not skip any instructions in this case.

Doing some archaeology, it seems handling for adr/adrp in prologues was
included with the original aarch64 port.  It might've been an oversight.

In the particular case of gdb.dwarf2/dw2-dir-file-name.exp, the analyzer skips
a couple instructions and leaves us in a nice spot where the address to the
variable "v" is already in w0. But no prologues exists.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29481
---
 gdb/aarch64-tdep.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index f747ebda1ab..0385bc18632 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -354,14 +354,6 @@ aarch64_analyze_prologue (struct gdbarch *gdbarch,
 
 	  regs[rd] = pv_subtract (regs[rn], regs[rm]);
 	}
-      else if (inst.opcode->iclass == pcreladdr
-	       && inst.operands[1].type == AARCH64_OPND_ADDR_ADRP)
-	{
-	  gdb_assert (aarch64_num_of_operands (inst.opcode) == 2);
-	  gdb_assert (inst.operands[0].type == AARCH64_OPND_Rd);
-
-	  regs[inst.operands[0].reg.regno] = pv_unknown ();
-	}
       else if (inst.opcode->iclass == branch_imm)
 	{
 	  /* Stop analysis on branch.  */
-- 
2.25.1

Re: [PATCH] [aarch64] Remove handling of ADR/ADRP from prologue analyzer

[Luis Machado]

On 8/17/22 09:33, Luis Machado via Gdb-patches wrote:
> As reported by Tom in https://sourceware.org/pipermail/gdb-patches/2022-August/191357.html,
> the aarch64 prologue analyzer considers the adrp instruction in the
> gdb.dwarf2/dw2-dir-file-name.exp testcase to be part of a prologue.
> 
> The function has no prologue though, and it only loads the volatile variable
> from memory.  GDB should not skip any instructions in this case.
> 
> Doing some archaeology, it seems handling for adr/adrp in prologues was
> included with the original aarch64 port.  It might've been an oversight.
> 
> In the particular case of gdb.dwarf2/dw2-dir-file-name.exp, the analyzer skips
> a couple instructions and leaves us in a nice spot where the address to the
> variable "v" is already in w0. But no prologues exists.
> 
> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29481
> ---
>   gdb/aarch64-tdep.c | 8 --------
>   1 file changed, 8 deletions(-)
> 
> diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
> index f747ebda1ab..0385bc18632 100644
> --- a/gdb/aarch64-tdep.c
> +++ b/gdb/aarch64-tdep.c
> @@ -354,14 +354,6 @@ aarch64_analyze_prologue (struct gdbarch *gdbarch,
>   
>   	  regs[rd] = pv_subtract (regs[rn], regs[rm]);
>   	}
> -      else if (inst.opcode->iclass == pcreladdr
> -	       && inst.operands[1].type == AARCH64_OPND_ADDR_ADRP)
> -	{
> -	  gdb_assert (aarch64_num_of_operands (inst.opcode) == 2);
> -	  gdb_assert (inst.operands[0].type == AARCH64_OPND_Rd);
> -
> -	  regs[inst.operands[0].reg.regno] = pv_unknown ();
> -	}
>         else if (inst.opcode->iclass == branch_imm)
>   	{
>   	  /* Stop analysis on branch.  */

Pushed now.