[PATCH 1/2] libsframe: add new dump_sframe_reloc

[Indu Bhagat]

PR libsframe/32589 - function start address is zero in SFrame section dump

This new function dumps the contents of a relocated SFrame section in
human readable text.

After the section contents are relocated, there is need to fixup the
function start address, which is what sframe_fde_tbl_reloc_fixup () is
about.  This is similar to the fixups done for other debug sections
before textual dump.  The function sframe_fde_tbl_reloc_fixup is
libsframe internal only and is not exposed.

Some caution is necessary though in making sure
sframe_fde_tbl_reloc_fixup is done in a version aware manner, when
future versions of the SFrame format are implemented.  For now, add a
version check as a reminder.

Note the new API dump_sframe_reloc (). This new API is exposed because
objdump / readelf will need it.  Update the library version information:
Since new interfaces have been added, set revision to 0, bump current
and age.

libsframe/
        * libtool.version: Bump current and age.  Use 2:0:1.
        * libsframe.ver: Add new API dump_sframe_reloc.
        (dump_sframe_reloc): New definition.
        * sframe-impl.h (sframe_fde_tbl_reloc_fixup): New declaration.
        * sframe.c (sframe_fde_tbl_reloc_fixup): New definition.

include/
        * sframe-api.h (dump_sframe_reloc): New declaration.
---
 include/sframe-api.h      |  5 +++++
 libsframe/libsframe.ver   |  1 +
 libsframe/libtool-version |  2 +-
 libsframe/sframe-dump.c   | 13 +++++++++++++
 libsframe/sframe-impl.h   |  2 ++
 libsframe/sframe.c        | 31 +++++++++++++++++++++++++++++++
 6 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/include/sframe-api.h b/include/sframe-api.h
index 77ba32b0f4b..5f13c4baf2c 100644
--- a/include/sframe-api.h
+++ b/include/sframe-api.h
@@ -189,6 +189,11 @@ sframe_decoder_get_funcdesc_v2 (sframe_decoder_ctx *ctx,
 extern void
 dump_sframe (sframe_decoder_ctx *decoder, uint64_t addr);
 
+/* SFrame textual dump - with relocation.  */
+extern void
+dump_sframe_reloc (sframe_decoder_ctx *dctx, uint64_t sec_addr,
+		   bool relocate_p);
+
 /* Get the base reg id from the FRE info.  Sets errp if fails.  */
 extern uint8_t
 sframe_fre_get_base_reg_id (sframe_frame_row_entry *fre, int *errp);
diff --git a/libsframe/libsframe.ver b/libsframe/libsframe.ver
index 57f5fb6c378..1f794134679 100644
--- a/libsframe/libsframe.ver
+++ b/libsframe/libsframe.ver
@@ -33,6 +33,7 @@ LIBSFRAME_1.0 {
     sframe_encoder_add_funcdesc_v2;
     sframe_encoder_write;
     dump_sframe;
+    dump_sframe_reloc;
     sframe_errmsg;
 
   local:
diff --git a/libsframe/libtool-version b/libsframe/libtool-version
index 9dcbe48e47d..5a961391f49 100644
--- a/libsframe/libtool-version
+++ b/libsframe/libtool-version
@@ -27,4 +27,4 @@
 #       then set age to 0.
 #
 # CURRENT:REVISION:AGE
-1:0:0
+2:0:1
diff --git a/libsframe/sframe-dump.c b/libsframe/sframe-dump.c
index 1fa508d9bad..a8fb132725f 100644
--- a/libsframe/sframe-dump.c
+++ b/libsframe/sframe-dump.c
@@ -218,6 +218,19 @@ dump_sframe_functions (sframe_decoder_ctx *sfd_ctx, uint64_t sec_addr)
     }
 }
 
+void
+dump_sframe_reloc (sframe_decoder_ctx *sfd_ctx, uint64_t sec_addr,
+		   bool relocate_p)
+{
+  if (relocate_p && sframe_fde_tbl_reloc_fixup (sfd_ctx))
+    {
+      printf ("\n Unexpected error in processing relocations.");
+      return;
+    }
+
+  dump_sframe (sfd_ctx, sec_addr);
+}
+
 void
 dump_sframe (sframe_decoder_ctx *sfd_ctx, uint64_t sec_addr)
 {
diff --git a/libsframe/sframe-impl.h b/libsframe/sframe-impl.h
index 1cada54ae9e..9887039c3c5 100644
--- a/libsframe/sframe-impl.h
+++ b/libsframe/sframe-impl.h
@@ -64,6 +64,8 @@ struct sframe_encoder_ctx
   size_t sfe_data_size;
 };
 
+int sframe_fde_tbl_reloc_fixup (sframe_decoder_ctx *dctx);
+
 #ifdef  __cplusplus
 }
 #endif
diff --git a/libsframe/sframe.c b/libsframe/sframe.c
index c2693b978ec..01cefa4d01c 100644
--- a/libsframe/sframe.c
+++ b/libsframe/sframe.c
@@ -102,6 +102,37 @@ sframe_ret_set_errno (int *errp, int error)
   return NULL;
 }
 
+/* If the input buffer containing the SFrame section has been relocated, there
+   will be a need to do fixups too.  The fixup merely accounts for the offset
+   of the byte from the start of the section.
+
+   Currently used by dump_sframe_reloc.  The caller must have decoded (and
+   hence, endian flipped) the input buffer before calling this function.  */
+
+int
+sframe_fde_tbl_reloc_fixup (sframe_decoder_ctx *dctx)
+{
+  uint8_t sframe_ver = sframe_decoder_get_version (dctx);
+  uint32_t num_fdes = sframe_decoder_get_num_fidx (dctx);
+  unsigned int buf_offset = 0;
+  sframe_func_desc_entry *fde;
+  uint32_t i = 0;
+
+  if (sframe_ver != SFRAME_VERSION_2 || !dctx->sfd_funcdesc)
+    return SFRAME_ERR;
+
+  buf_offset += sframe_decoder_get_hdr_size (dctx);
+  while (i < num_fdes)
+    {
+      fde = &dctx->sfd_funcdesc[i];
+      fde->sfde_func_start_address += buf_offset;
+      buf_offset += sizeof (sframe_func_desc_entry);
+      i++;
+    }
+
+  return 0;
+}
+
 /* Get the SFrame header size.  */
 
 static uint32_t
-- 
2.43.0