diff mbox series

[v6,3/4] include: libsframe: Add API to get RA undefined

Message ID 20250915110551.759931-4-jremus@linux.ibm.com
State New
Headers
Series sframe: Represent .cfi_undefined RA |

Commit Message

Jens Remus Sept. 15, 2025, 11:05 a.m. UTC 
  SFrame FREs without any offsets will later be used to represent an
undefined return address (RA) in SFrame.  This API can then be used,
for instance by libsframe when dumping SFrame stack trace information
(e.g. in objdump and readelf), to test for RA undefined.  Other users
of libsframe need the same capability.

include/
	* sframe-api.h (sframe_fre_get_ra_undefined_p): New declaration.

libsframe/
	* libsframe.ver (sframe_fre_get_ra_undefined_p): List new API.
	* sframe.c (sframe_fre_get_ra_undefined_p): New definition.

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

Notes (jremus):
    Changes in V5:
    - Make this a preparatory patch for the next one.  Instead of using
      SFRAME_V2_FRE_RA_UNDEFINED_P test FRE offset count for zero.
    - Reword commit message.
    
    Changes in V4:
    - New patch.  Alternative to adding an API to get the FRE offset count.

 include/sframe-api.h    |  6 ++++++
 libsframe/libsframe.ver |  5 +++++
 libsframe/sframe.c      | 18 ++++++++++++++++++
 3 files changed, 29 insertions(+)
diff mbox series

Patch

diff --git a/include/sframe-api.h b/include/sframe-api.h
index 8c26257fb643..507f806ab4c4 100644
--- a/include/sframe-api.h
+++ b/include/sframe-api.h
@@ -230,6 +230,12 @@  extern bool
 sframe_fre_get_ra_mangled_p (sframe_decoder_ctx *dctx,
 			     sframe_frame_row_entry *fre, int *errp);
 
+/* Get whether the RA is undefined (i.e. outermost frame).  */
+
+bool
+sframe_fre_get_ra_undefined_p (const sframe_decoder_ctx *dctx ATTRIBUTE_UNUSED,
+			       const sframe_frame_row_entry *fre, int *errp);
+
 /* The SFrame Encoder.  */
 
 /* Create an encoder context with the given SFrame format version VER, FLAGS
diff --git a/libsframe/libsframe.ver b/libsframe/libsframe.ver
index 8cc80da2f26a..4286a72b93bc 100644
--- a/libsframe/libsframe.ver
+++ b/libsframe/libsframe.ver
@@ -41,3 +41,8 @@  LIBSFRAME_2.0 {
   local:
     *;
 } LIBSFRAME_0.0;
+
+LIBSFRAME_2.1 {
+  global:
+    sframe_fre_get_ra_undefined_p;
+} LIBSFRAME_2.0;
diff --git a/libsframe/sframe.c b/libsframe/sframe.c
index f56742ee1a11..bd39780a9135 100644
--- a/libsframe/sframe.c
+++ b/libsframe/sframe.c
@@ -131,6 +131,12 @@  sframe_get_fre_ra_mangled_p (uint8_t fre_info)
   return SFRAME_V1_FRE_MANGLED_RA_P (fre_info);
 }
 
+static bool
+sframe_get_fre_ra_undefined_p (uint8_t fre_info)
+{
+  return SFRAME_V1_FRE_OFFSET_COUNT (fre_info) == 0;
+}
+
 /* Access functions for info from function descriptor entry.  */
 
 static uint32_t
@@ -777,6 +783,18 @@  sframe_fre_get_ra_mangled_p (sframe_decoder_ctx *dctx ATTRIBUTE_UNUSED,
   return sframe_get_fre_ra_mangled_p (fre->fre_info);
 }
 
+/* Get whether the RA is undefined (i.e. outermost frame).  */
+
+bool
+sframe_fre_get_ra_undefined_p (const sframe_decoder_ctx *dctx ATTRIBUTE_UNUSED,
+			       const sframe_frame_row_entry *fre, int *errp)
+{
+  if (fre == NULL || !sframe_fre_sanity_check_p (fre))
+    return sframe_set_errno (errp, SFRAME_ERR_FRE_INVAL);
+
+  return sframe_get_fre_ra_undefined_p (fre->fre_info);
+}
+
 static int
 sframe_frame_row_entry_copy (sframe_frame_row_entry *dst,
 			     sframe_frame_row_entry *src)