diff mbox series

[v3,08/15] gas: Refactor SFrame CFI opcode DW_CFA_register processing

Message ID 20240412144718.4191286-9-jremus@linux.ibm.com
State New
Headers
Series sframe: Enhancements to SFrame info generation |

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Commit Message

Jens Remus April 12, 2024, 2:47 p.m. UTC 
  Refactor SFrame processing of CFI opcode DW_CFA_register into a separate
function. This harmonizes the CFI opcode processing.

While at it reword the comment on CFI opcodes that are not processed.

This is a purely mechanical change.

gas/
	* gen-sframe.c (sframe_do_cfi_insn, sframe_xlate_do_register):
	Refactor SFrame CFI opcode DW_CFA_register processing.

Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---

Notes (jremus):
    Changes v2 -> v3:
    - New patch.

 gas/gen-sframe.c | 37 ++++++++++++++++++++++++++-----------
 1 file changed, 26 insertions(+), 11 deletions(-)

Comments

Indu Bhagat April 18, 2024, 7:40 a.m. UTC | #1 
On 4/12/24 07:47, Jens Remus wrote:
> Refactor SFrame processing of CFI opcode DW_CFA_register into a separate
> function. This harmonizes the CFI opcode processing.
> 
> While at it reword the comment on CFI opcodes that are not processed.
> 
> This is a purely mechanical change.
> 
> gas/
> 	* gen-sframe.c (sframe_do_cfi_insn, sframe_xlate_do_register):
> 	Refactor SFrame CFI opcode DW_CFA_register processing.
> 

OK.

Thanks

> Signed-off-by: Jens Remus <jremus@linux.ibm.com>
> ---
> 
> Notes (jremus):
>      Changes v2 -> v3:
>      - New patch.
> 
>   gas/gen-sframe.c | 37 ++++++++++++++++++++++++++-----------
>   1 file changed, 26 insertions(+), 11 deletions(-)
> 
> diff --git a/gas/gen-sframe.c b/gas/gen-sframe.c
> index fe8b24906c1b..f47f51c7a354 100644
> --- a/gas/gen-sframe.c
> +++ b/gas/gen-sframe.c
> @@ -1108,6 +1108,28 @@ sframe_xlate_do_val_offset (struct sframe_xlate_ctx *xlate_ctx ATTRIBUTE_UNUSED,
>     return SFRAME_XLATE_OK;
>   }
>   
> +/* Translate DW_CFA_register into SFrame context.
> +   Return SFRAME_XLATE_OK if success.  */
> +
> +static int
> +sframe_xlate_do_register (struct sframe_xlate_ctx *xlate_ctx ATTRIBUTE_UNUSED,
> +			  struct cfi_insn_data *cfi_insn)
> +{
> +  /* Previous value of register1 is register2.  However, if the specified
> +     register1 is not interesting (SP, FP, or RA reg), the current DW_CFA_register
> +     instruction can be safely skipped without sacrificing the asynchronicity of
> +     stack trace information.  */
> +  if (cfi_insn->u.rr.reg1 == SFRAME_CFA_SP_REG
> +#ifdef SFRAME_FRE_RA_TRACKING
> +      || (cfi_insn->u.rr.reg1 == SFRAME_CFA_RA_REG)
> +#endif
> +      || cfi_insn->u.rr.reg1 == SFRAME_CFA_FP_REG)
> +    return SFRAME_XLATE_ERR_NOTREPRESENTED;  /* Not represented.  */
> +
> +  /* Safe to skip.  */
> +  return SFRAME_XLATE_OK;
> +}
> +
>   /* Translate DW_CFA_remember_state into SFrame context.
>      Return SFRAME_XLATE_OK if success.  */
>   
> @@ -1296,19 +1318,12 @@ sframe_do_cfi_insn (struct sframe_xlate_ctx *xlate_ctx,
>       case DW_CFA_GNU_window_save:
>         err = sframe_xlate_do_gnu_window_save (xlate_ctx, cfi_insn);
>         break;
> -    /* Other CFI opcodes are not processed at this time.
> -       These do not impact the coverage of the basic stack tracing
> -       information as conveyed in the SFrame format.
> -	- DW_CFA_register,
> -	- etc.  */
>       case DW_CFA_register:
> -      if (cfi_insn->u.rr.reg1 == SFRAME_CFA_SP_REG
> -#ifdef SFRAME_FRE_RA_TRACKING
> -	  || cfi_insn->u.rr.reg1 == SFRAME_CFA_RA_REG
> -#endif
> -	  || cfi_insn->u.rr.reg1 == SFRAME_CFA_FP_REG)
> -	err = SFRAME_XLATE_ERR_NOTREPRESENTED;
> +      err = sframe_xlate_do_register (xlate_ctx, cfi_insn);
>         break;
> +    /* Following CFI opcodes are not processed at this time.
> +       These do not impact the coverage of the basic stack tracing
> +       information as conveyed in the SFrame format.  */
>       case DW_CFA_undefined:
>       case DW_CFA_same_value:
>         break;
diff mbox series

Patch

diff --git a/gas/gen-sframe.c b/gas/gen-sframe.c
index fe8b24906c1b..f47f51c7a354 100644
--- a/gas/gen-sframe.c
+++ b/gas/gen-sframe.c
@@ -1108,6 +1108,28 @@  sframe_xlate_do_val_offset (struct sframe_xlate_ctx *xlate_ctx ATTRIBUTE_UNUSED,
   return SFRAME_XLATE_OK;
 }
 
+/* Translate DW_CFA_register into SFrame context.
+   Return SFRAME_XLATE_OK if success.  */
+
+static int
+sframe_xlate_do_register (struct sframe_xlate_ctx *xlate_ctx ATTRIBUTE_UNUSED,
+			  struct cfi_insn_data *cfi_insn)
+{
+  /* Previous value of register1 is register2.  However, if the specified
+     register1 is not interesting (SP, FP, or RA reg), the current DW_CFA_register
+     instruction can be safely skipped without sacrificing the asynchronicity of
+     stack trace information.  */
+  if (cfi_insn->u.rr.reg1 == SFRAME_CFA_SP_REG
+#ifdef SFRAME_FRE_RA_TRACKING
+      || (cfi_insn->u.rr.reg1 == SFRAME_CFA_RA_REG)
+#endif
+      || cfi_insn->u.rr.reg1 == SFRAME_CFA_FP_REG)
+    return SFRAME_XLATE_ERR_NOTREPRESENTED;  /* Not represented.  */
+
+  /* Safe to skip.  */
+  return SFRAME_XLATE_OK;
+}
+
 /* Translate DW_CFA_remember_state into SFrame context.
    Return SFRAME_XLATE_OK if success.  */
 
@@ -1296,19 +1318,12 @@  sframe_do_cfi_insn (struct sframe_xlate_ctx *xlate_ctx,
     case DW_CFA_GNU_window_save:
       err = sframe_xlate_do_gnu_window_save (xlate_ctx, cfi_insn);
       break;
-    /* Other CFI opcodes are not processed at this time.
-       These do not impact the coverage of the basic stack tracing
-       information as conveyed in the SFrame format.
-	- DW_CFA_register,
-	- etc.  */
     case DW_CFA_register:
-      if (cfi_insn->u.rr.reg1 == SFRAME_CFA_SP_REG
-#ifdef SFRAME_FRE_RA_TRACKING
-	  || cfi_insn->u.rr.reg1 == SFRAME_CFA_RA_REG
-#endif
-	  || cfi_insn->u.rr.reg1 == SFRAME_CFA_FP_REG)
-	err = SFRAME_XLATE_ERR_NOTREPRESENTED;
+      err = sframe_xlate_do_register (xlate_ctx, cfi_insn);
       break;
+    /* Following CFI opcodes are not processed at this time.
+       These do not impact the coverage of the basic stack tracing
+       information as conveyed in the SFrame format.  */
     case DW_CFA_undefined:
     case DW_CFA_same_value:
       break;