[binutils-gdb] [gdb/record] Fix syscall exit recording for riscv

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=a570ac19e30c17211f414c13af031b0e093b4cc1

commit a570ac19e30c17211f414c13af031b0e093b4cc1
Author: Tom de Vries <[email protected]>
Date:   Wed Mar 25 14:12:11 2026 +0100

    [gdb/record] Fix syscall exit recording for riscv
    
    [ Submitted earlier [1] with $subject: "[gdb/record] Fix syscall recording for
    riscv". ]
    
    On riscv64-linux, I run into:
    ...
    (gdb) continue^M
    Continuing.^M
    The next instruction is syscall exit_group.  It will make the program exit. \
      Do you want to stop the program?([y] or n) yes^M
    Process record: failed to record execution log.^M
    ^M
    Program stopped.^M
    __GI__exit (status=status@entry=0) at _exit.c:30^M
    warning: 30     _exit.c: No such file or directory^M
    (gdb) FAIL: gdb.reverse/sigall-reverse.exp: continue to signal exit
    ...
    
    The problem is here in record_insn_len4:
    ...
            /* We are in linux mode.  */
            return (read_reg (RISCV_A7_REGNUM, reg_val)
                    && m_gdbarch->riscv_syscall_record (m_regcache, reg_val) == 0);
    ...
    where return values 1 and -1 are handled the same.
    
    Fix this in the usual way, by passing through the 1 value all the way to
    riscv_process_record.  That requires changing a few functions from type bool
    to int.  That's also the case for record_insn_len4, where I factored out
    record_insn_len4_1 to keep changes to a minimum.
    
    Also introduce a common enum record_result, and use it instead of hardcoded
    1/0/-1.
    
    Tested on riscv64-linux.
    
    Approved-By: Guinevere Larsen <[email protected]>
    
    [1] https://sourceware.org/pipermail/gdb-patches/2026-February/225384.html

Diff:
---
 gdb/record-full.h | 15 +++++++++++++
 gdb/riscv-tdep.c  | 64 ++++++++++++++++++++++++++++++++++---------------------
 2 files changed, 55 insertions(+), 24 deletions(-)

diff --git a/gdb/record-full.h b/gdb/record-full.h
index ea78f6e886c..51effe74560 100644
--- a/gdb/record-full.h
+++ b/gdb/record-full.h
@@ -24,6 +24,21 @@
 
 extern bool record_full_memory_query;
 
+/* Type to be used to return values in the gdbarch_process_record hook.  */
+
+enum record_result
+{
+  /* Process record does not support instruction $hex at address $hex.
+     Process record: failed to record execution log.  */
+  RECORD_UNSUPPORTED = -2,
+  /* Process record: failed to record execution log.  */
+  RECORD_FAILURE = -1,
+  /* No failure.  */
+  RECORD_SUCCESS = 0,
+  /* Process record: inferior program stopped.  */
+  RECORD_UNKNOWN = 1
+};
+
 extern int record_full_arch_list_add_reg (struct regcache *regcache, int num);
 extern int record_full_arch_list_add_mem (CORE_ADDR addr, int len);
 extern int record_full_arch_list_add_end (void);
diff --git a/gdb/riscv-tdep.c b/gdb/riscv-tdep.c
index ebecd1e79d5..6b5c9c02d46 100644
--- a/gdb/riscv-tdep.c
+++ b/gdb/riscv-tdep.c
@@ -5199,26 +5199,14 @@ class riscv_recorded_insn final
   }
 
   /* Returns true if instruction is successfully recorded.  The length of
-     the instruction must be equal to 4 bytes.  */
+     the instruction must be equal to 4 bytes.  Helper function for
+     record_insn_len4.  */
   bool
-  record_insn_len4 (ULONGEST ival) noexcept
+  record_insn_len4_1 (ULONGEST ival) noexcept
   {
     mem_len len = 0;
-    ULONGEST reg_val = 0;
-
-    if (is_ecall_insn (ival))
-      {
-	/* We are in baremetal mode.  */
-	if (m_in_baremetal_mode)
-	  {
-	    warning (_("Syscall record is not supported"));
-	    return false;
-	  }
 
-	/* We are in linux mode.  */
-	return (read_reg (RISCV_A7_REGNUM, reg_val)
-		&& m_gdbarch->riscv_syscall_record (m_regcache, reg_val) == 0);
-      }
+    gdb_assert (!is_ecall_insn (ival));
 
     if (is_ebreak_insn (ival))
       return true;
@@ -5256,6 +5244,32 @@ class riscv_recorded_insn final
     return false;
   }
 
+  /* Returns RECORD_SUCCESS if instruction is successfully recorded.  The
+     length of the instruction must be equal to 4 bytes.  */
+  int
+  record_insn_len4 (ULONGEST ival) noexcept
+  {
+    ULONGEST reg_val = 0;
+
+    if (is_ecall_insn (ival))
+      {
+	/* We are in baremetal mode.  */
+	if (m_in_baremetal_mode)
+	  {
+	    warning (_("Syscall record is not supported"));
+	    return RECORD_FAILURE;
+	  }
+
+	/* We are in linux mode.  */
+	if (!read_reg (RISCV_A7_REGNUM, reg_val))
+	  return RECORD_FAILURE;
+
+	return m_gdbarch->riscv_syscall_record (m_regcache, reg_val);
+      }
+
+    return record_insn_len4_1 (ival) ? RECORD_SUCCESS : RECORD_FAILURE;
+  }
+
   /* Returns true if instruction is successfully recorded.  The length of
      the instruction must be equal to 2 bytes.  */
   bool
@@ -5388,8 +5402,9 @@ class riscv_recorded_insn final
   }
 
 public:
-  /* Record instruction at address addr.  Returns false if error happened.  */
-  bool
+  /* Record instruction at address addr.  Return RECORD_FAILURE if error
+     happened.  */
+  int
   record (gdbarch *gdbarch, struct regcache *regcache, CORE_ADDR addr) noexcept
   {
     gdb_assert (gdbarch != nullptr);
@@ -5412,14 +5427,14 @@ public:
     catch (const gdb_exception_error &ex)
       {
 	warning ("%s", ex.what ());
-	return false;
+	return RECORD_FAILURE;
       }
 
     if (!save_reg (RISCV_PC_REGNUM))
-      return false;
+      return RECORD_FAILURE;
 
     if (insn_length == 2)
-      return record_insn_len2 (ival);
+      return record_insn_len2 (ival) ? RECORD_SUCCESS : RECORD_FAILURE;
 
     if (insn_length == 4)
       return record_insn_len4 (ival);
@@ -5431,7 +5446,7 @@ public:
 
     warning (_("Can not record unknown instruction (opcode = %s)"),
 	     hex_string (ival));
-    return false;
+    return RECORD_FAILURE;
   }
 };
 
@@ -5447,8 +5462,9 @@ riscv_process_record (struct gdbarch *gdbarch, struct regcache *regcache,
   gdb_assert (regcache != nullptr);
 
   riscv_recorded_insn insn;
-  if (!insn.record (gdbarch, regcache, addr))
-    return -1;
+  int res = insn.record (gdbarch, regcache, addr);
+  if (res != RECORD_SUCCESS)
+    return res;
 
   if (record_full_arch_list_add_end ())
     return -1;