>From 1e4dee2dae0ad08fecb50dcced3d00c6cfffd932 Mon Sep 17 00:00:00 2001
From: Robert Dubner mailto:rdub...@symas.com
Date: Sun, 11 May 2025 13:43:32 -0400
Subject: [PATCH] cobol: Eliminate padding bytes from cbl_declarative_t.
[PR119377]
By changing the type of a variable in the cbl_declarative_t structure from
"bool"
to "uint32_t", three uninitialized padding bytes were turned into
initialized
bytes. This eliminates the valgrind error caused by those uninitialized
values.
This is an interim fix, which expediently eliminates the valgrind problem.
The
underlying design flaw, which involves turning a host-side C++ structure
into
a run-time data block, is slated for complete replacement in the next few
weeks.
libgcobol/ChangeLog:
PR cobol/119377
* common-defs.h: (struct cbl_declaratives_t): Change "bool global"
to
"uint32_t global".
---
libgcobol/common-defs.h | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/libgcobol/common-defs.h b/libgcobol/common-defs.h
index 026f377e74b2..e3471c5ccc3d 100644
--- a/libgcobol/common-defs.h
+++ b/libgcobol/common-defs.h
@@ -458,11 +458,25 @@ struct cbl_enabled_exception_t {
struct cbl_declarative_t {
enum { files_max = 16 };
size_t section; // implies program
- bool global;
+ uint32_t global; // See the note below
ec_type_t type;
uint32_t nfile, files[files_max];
cbl_file_mode_t mode;
+/* The ::global member originally was "bool global". A bool, however,
occupies
+ only one byte of storage. The structure, in turn, is constructed on
+ four-byte boundaries for members, so there were three padding bytes
between
+ the single byte of global and the ::type member.
+
+ When used to create a "blob", where the structure was treated as a
stream
+ of bytes that were used to create a constructor for an array of
bytes,
+ valgrind noticed that those three padding bytes were not initialized,
and
+ generated the appropriate error message. This made it hard to find
other
+ problems.
+
+ Changing the declaration from "bool" to "uint32_t" seems to have
eliminated
+ the valgrind error without affecting overall performance. */
+
cbl_declarative_t( cbl_file_mode_t mode = file_mode_none_e )
: section(0), global(false)
, type(ec_none_e)
--
2.34.1
