* [binutils-gdb] libsframe: revisit sframe_find_fre API
@ 2023-05-26 6:57 Indu Bhagat
0 siblings, 0 replies; only message in thread
From: Indu Bhagat @ 2023-05-26 6:57 UTC (permalink / raw)
To: bfd-cvs, gdb-cvs
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=83c219872b2131546ccec7edc57eb47c64b8911d
commit 83c219872b2131546ccec7edc57eb47c64b8911d
Author: Indu Bhagat <indu.bhagat@oracle.com>
Date: Thu May 25 23:44:09 2023 -0700
libsframe: revisit sframe_find_fre API
Inspite of implementing a rather simple functionality, this function was
relatively difficult to follow, and maintain. Some changes are done now
to address that - refactor the function and use better names to make it
more readable.
The changes to the implementation do not cause any change in the
contract of the API.
libsframe/
* sframe.c (sframe_fre_get_end_ip_offset): to here...
(sframe_find_fre): Refactor some bits from...
Diff:
---
libsframe/sframe.c | 83 ++++++++++++++++++++++++++++++++----------------------
1 file changed, 49 insertions(+), 34 deletions(-)
diff --git a/libsframe/sframe.c b/libsframe/sframe.c
index 72b221349ad..dadce2c1262 100644
--- a/libsframe/sframe.c
+++ b/libsframe/sframe.c
@@ -980,6 +980,32 @@ sframe_get_funcdesc_with_addr (sframe_decoder_ctx *ctx,
return sframe_ret_set_errno (errp, SFRAME_ERR_FDE_NOTFOUND);
}
+/* Get the end IP offset for the FRE at index i in the FDEP. The buffer FRES
+ is the starting location for the FRE. */
+
+static uint32_t
+sframe_fre_get_end_ip_offset (sframe_func_desc_entry *fdep, unsigned int i,
+ const char *fres)
+{
+ uint32_t end_ip_offset;
+ uint32_t fre_type;
+
+ fre_type = sframe_get_fre_type (fdep);
+
+ /* Get the start address of the next FRE in sequence. */
+ if (i < fdep->sfde_func_num_fres - 1)
+ {
+ sframe_decode_fre_start_address (fres, &end_ip_offset, fre_type);
+ end_ip_offset -= 1;
+ }
+ else
+ /* The end IP offset for the FRE needs to be deduced from the function
+ size. */
+ end_ip_offset = fdep->sfde_func_size - 1;
+
+ return end_ip_offset;
+}
+
/* Find the SFrame Row Entry which contains the PC. Returns
SFRAME_ERR if failure. */
@@ -987,14 +1013,15 @@ int
sframe_find_fre (sframe_decoder_ctx *ctx, int32_t pc,
sframe_frame_row_entry *frep)
{
+ sframe_frame_row_entry cur_fre;
sframe_func_desc_entry *fdep;
- uint32_t start_address, i;
- sframe_frame_row_entry cur_fre, next_fre;
- const char *fres;
unsigned int fre_type, fde_type;
- size_t esz;
- int err = 0;
+ uint32_t end_ip_offset, i;
+ int32_t start_ip, end_ip;
+ int32_t func_start_addr;
+ const char *fres;
size_t size = 0;
+ int err = 0;
/* For regular FDEs (i.e. fde_type SFRAME_FDE_TYPE_PCINC),
where the start address in the FRE is an offset from start pc,
use a bitmask with all bits set so that none of the address bits are
@@ -1022,40 +1049,28 @@ sframe_find_fre (sframe_decoder_ctx *ctx, int32_t pc,
bitmask = 0xff;
fres = ctx->sfd_fres + fdep->sfde_func_start_fre_off;
+ func_start_addr = fdep->sfde_func_start_address;
+
for (i = 0; i < fdep->sfde_func_num_fres; i++)
{
- err = sframe_decode_fre (fres, &next_fre, fre_type, &esz);
- start_address = next_fre.fre_start_addr;
+ err = sframe_decode_fre (fres, &cur_fre, fre_type, &size);
+ if (err)
+ return sframe_set_errno (&err, SFRAME_ERR_FRE_INVAL);
- if (((fdep->sfde_func_start_address
- + (int32_t) start_address) & bitmask) <= (pc & bitmask))
+ start_ip = func_start_addr + cur_fre.fre_start_addr;
+ end_ip_offset = sframe_fre_get_end_ip_offset (fdep, i, fres + size);
+ end_ip = func_start_addr + end_ip_offset;
+
+ if ((start_ip & bitmask) > (pc & bitmask))
+ return sframe_set_errno (&err, SFRAME_ERR_FRE_INVAL);
+
+ if (((start_ip & bitmask) <= (pc & bitmask))
+ && (end_ip & bitmask) >= (pc & bitmask))
{
- sframe_frame_row_entry_copy (&cur_fre, &next_fre);
-
- /* Get the next FRE in sequence. */
- if (i < fdep->sfde_func_num_fres - 1)
- {
- sp += esz;
- err = sframe_decode_fre (fres, &next_fre, fre_type, &esz);
-
- /* Sanity check the next FRE. */
- if (!sframe_fre_sanity_check_p (&next_fre))
- return sframe_set_errno (&err, SFRAME_ERR_FRE_INVAL);
-
- size = next_fre.fre_start_addr;
- }
- else size = fdep->sfde_func_size;
-
- /* If the cur FRE is the one that contains the PC, return it. */
- if (((fdep->sfde_func_start_address
- + (int32_t)size) & bitmask) > (pc & bitmask))
- {
- sframe_frame_row_entry_copy (frep, &cur_fre);
- return 0;
- }
+ sframe_frame_row_entry_copy (frep, &cur_fre);
+ return 0;
}
- else
- return sframe_set_errno (&err, SFRAME_ERR_FRE_INVAL);
+ fres += size;
}
return sframe_set_errno (&err, SFRAME_ERR_FDE_INVAL);
}
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