[PATCH] libdw: Initialize variables in getcfi_gnu_eh_frame.

[PATCH] libdw: Initialize variables in getcfi_gnu_eh_frame.

[Mark Wielaard]

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Some older GCCs are not clever enough to realize that when search_table
is NULL not only are search_table_entries and search_table_encoding not
initialized, they are also not used. Giving "may be used uninitialized"
errors.

Signed-off-by: Mark Wielaard <mjw@redhat.com>
---
 libdw/ChangeLog          | 5 +++++
 libdw/dwarf_getcfi_elf.c | 6 +++---
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index 37f94df..c199707 100644
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,3 +1,8 @@
+2014-11-27  Mark Wielaard  <mjw@redhat.com>
+
+	* dwarf_getcfi_elf.c (getcfi_gnu_eh_frame): Initialize
+	search_table_entries and search_table_encoding.
+
 2014-11-24  Mark Wielaard  <mjw@redhat.com>
 
 	* dwarf_getsrclines.c (read_srclines): Check line_range is not zero
diff --git a/libdw/dwarf_getcfi_elf.c b/libdw/dwarf_getcfi_elf.c
index a423ef3..61ca60d 100644
--- a/libdw/dwarf_getcfi_elf.c
+++ b/libdw/dwarf_getcfi_elf.c
@@ -1,5 +1,5 @@
 /* Get CFI from ELF file's exception-handling info.
-   Copyright (C) 2009-2010 Red Hat, Inc.
+   Copyright (C) 2009-2010, 2014 Red Hat, Inc.
    This file is part of elfutils.
 
    This file is free software; you can redistribute it and/or modify
@@ -140,8 +140,8 @@ getcfi_gnu_eh_frame (Elf *elf, const GElf_Ehdr *ehdr, const GElf_Phdr *phdr)
     }
 
   Dwarf_Addr eh_frame_ptr;
-  size_t search_table_entries;
-  uint8_t search_table_encoding;
+  size_t search_table_entries = 0;
+  uint8_t search_table_encoding = 0;
   const uint8_t *search_table = parse_eh_frame_hdr (data->d_buf, phdr->p_filesz,
 						    phdr->p_vaddr, ehdr,
 						    &eh_frame_ptr,
-- 
1.9.3

Re: [PATCH] libdw: Initialize variables in getcfi_gnu_eh_frame.

[Mark Wielaard]

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On Thu, 2014-11-27 at 23:45 +0100, Mark Wielaard wrote:
> Some older GCCs are not clever enough to realize that when search_table
> is NULL not only are search_table_entries and search_table_encoding not
> initialized, they are also not used. Giving "may be used uninitialized"
> errors.
> [...]
> +++ b/libdw/ChangeLog
> @@ -1,3 +1,8 @@
> +2014-11-27  Mark Wielaard  <mjw@redhat.com>
> +
> +	* dwarf_getcfi_elf.c (getcfi_gnu_eh_frame): Initialize
> +	search_table_entries and search_table_encoding.

I pushed this to master now.