[binutils-gdb] libctf warnings

[Alan Modra <amodra@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=59497587af9e1c5f029ab0bb106103dab30a5f5d

commit 59497587af9e1c5f029ab0bb106103dab30a5f5d
Author: Alan Modra <amodra@gmail.com>
Date:   Tue Apr 9 08:53:35 2024 +0930

    libctf warnings
    
    Seen with every compiler I have if using -fno-inline:
    home/alan/src/binutils-gdb/libctf/ctf-create.c: In function ‘ctf_add_encoded’:
    /home/alan/src/binutils-gdb/libctf/ctf-create.c:555:3: warning: ‘encoding’ may be used uninitialized [-Wmaybe-uninitialized]
      555 |   memcpy (dtd->dtd_vlen, &encoding, sizeof (encoding));
    
    Seen with gcc-4.9 and probably others at lower optimisation levels:
    home/alan/src/binutils-gdb/libctf/ctf-serialize.c: In function 'symtypetab_density':
    /home/alan/src/binutils-gdb/libctf/ctf-serialize.c:211:18: warning: 'sym' may be used uninitialized in this function [-Wmaybe-uninitialized]
        if (*max < sym->st_symidx)
    
    Seen with gcc-4.5 and probably others at lower optimisation levels:
    /home/alan/src/binutils-gdb/libctf/ctf-types.c:1649:21: warning: 'tp' may be used uninitialized in this function
    /home/alan/src/binutils-gdb/libctf/ctf-link.c:765:16: warning: 'parent_i' may be used uninitialized in this function
    
    Also with gcc-4.5:
    In file included from /home/alan/src/binutils-gdb/libctf/ctf-endian.h:25:0,
                     from /home/alan/src/binutils-gdb/libctf/ctf-archive.c:24:
    /home/alan/src/binutils-gdb/libctf/swap.h:70:0: warning: "_Static_assert" redefined
    /usr/include/sys/cdefs.h:568:0: note: this is the location of the previous definition
    
            * swap.h (_Static_assert): Don't define if already defined.
            * ctf-serialize.c (symtypetab_density): Merge two
            CTF_SYMTYPETAB_FORCE_INDEXED blocks.
            * ctf-create.c (ctf_add_encoded): Avoid "encoding" may be used
            uninitialized warning.
            * ctf-link.c (ctf_link_deduplicating_open_inputs): Avoid
            "parent_i" may be used uninitialized warning.
            * ctf-types.c (ctf_type_rvisit): Avoid "tp" may be used
            uninitialized warning.

Diff:
---
 libctf/ctf-create.c    | 4 ++++
 libctf/ctf-link.c      | 2 +-
 libctf/ctf-serialize.c | 8 +++-----
 libctf/ctf-types.c     | 2 +-
 libctf/swap.h          | 2 ++
 5 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/libctf/ctf-create.c b/libctf/ctf-create.c
index d0255e5ba7f..21fbad714a9 100644
--- a/libctf/ctf-create.c
+++ b/libctf/ctf-create.c
@@ -551,6 +551,10 @@ ctf_add_encoded (ctf_dict_t *fp, uint32_t flag,
     case CTF_K_FLOAT:
       encoding = CTF_FP_DATA (ep->cte_format, ep->cte_offset, ep->cte_bits);
       break;
+    default:
+      /* ctf_assert is opaque with -fno-inline.  This dead code avoids
+	 a warning about "encoding" being used uninitialized.  */
+      return CTF_ERR;
     }
   memcpy (dtd->dtd_vlen, &encoding, sizeof (encoding));
 
diff --git a/libctf/ctf-link.c b/libctf/ctf-link.c
index d5433b9d9bd..360bc1a0e63 100644
--- a/libctf/ctf-link.c
+++ b/libctf/ctf-link.c
@@ -762,7 +762,7 @@ ctf_link_deduplicating_open_inputs (ctf_dict_t *fp, ctf_dynhash_t *cu_names,
       ctf_link_input_t *one_input;
       ctf_dict_t *one_fp;
       ctf_dict_t *parent_fp = NULL;
-      uint32_t parent_i;
+      uint32_t parent_i = 0;
       ctf_next_t *j = NULL;
 
       /* If we are processing CU names, get the real input.  All the inputs
diff --git a/libctf/ctf-serialize.c b/libctf/ctf-serialize.c
index 8645f32ab20..11cbe75601e 100644
--- a/libctf/ctf-serialize.c
+++ b/libctf/ctf-serialize.c
@@ -202,17 +202,15 @@ symtypetab_density (ctf_dict_t *fp, ctf_dict_t *symfp, ctf_dynhash_t *symhash,
 	    }
 
 	  ctf_dynhash_remove (linker_known, name);
-	}
-      *unpadsize += sizeof (uint32_t);
-      (*count)++;
 
-      if (!(flags & CTF_SYMTYPETAB_FORCE_INDEXED))
-	{
 	  if (*max < sym->st_symidx)
 	    *max = sym->st_symidx;
 	}
       else
 	(*max)++;
+
+      *unpadsize += sizeof (uint32_t);
+      (*count)++;
     }
   if (err != ECTF_NEXT_END)
     {
diff --git a/libctf/ctf-types.c b/libctf/ctf-types.c
index 6dc723d61ea..0eaafa13619 100644
--- a/libctf/ctf-types.c
+++ b/libctf/ctf-types.c
@@ -1646,7 +1646,7 @@ ctf_type_rvisit (ctf_dict_t *fp, ctf_id_t type, ctf_visit_f *func,
 {
   ctf_dict_t *ofp = fp;
   ctf_id_t otype = type;
-  const ctf_type_t *tp;
+  const ctf_type_t *tp = NULL;
   const ctf_dtdef_t *dtd;
   unsigned char *vlen;
   ssize_t size, increment, vbytes;
diff --git a/libctf/swap.h b/libctf/swap.h
index d004dc14348..2e2b6973531 100644
--- a/libctf/swap.h
+++ b/libctf/swap.h
@@ -67,8 +67,10 @@ bswap_64 (uint64_t v)
 /* < C11? define away static assertions.  */
 
 #if !defined (__STDC_VERSION__) || __STDC_VERSION__ < 201112L
+#ifndef _Static_assert
 #define _Static_assert(cond, err)
 #endif
+#endif
 
 /* Swap the endianness of something.  */