check for internal memory bounds with new flag "memory-check" (implie…

…d with --debug)

related to [bugs:#896]

some validation of internal memory used during CALL; this can help in finding otherwise hard to diagnose overwrite of memory and as it is only done on CALL has a much smaller footprint than -fec=bounds (as both check different aspects at different places it is also reasonable to use both)

cobc:
* flag.def, cobc.c (cobc_deciph_memory_check), tree.h: new compile flag -fmemory-check, implied with --debug
* typeck.c (cb_emit_call), tree.h (cb_field): new field attribute flag_used_in_call
* codegen.c (output_local_base_cache, output_nonlocal_base_cache): generate fencing data fields for fields with flag_used_in_call
* codegen.c (output_call_cache): generate fencing data fields for cob_call_union fields (call pointers)
* codegen.c (output_memory_check_call): new function to output generate fencing data fields for flag_used_in_call
* codeoptim.def, codeoptim.c, codegen.c: new entry COB_CHK_MEMORYFENCE

additional:
* codegen.c: only increment/decrement output_indent_level by indent_adjust_level
* restored some parts of codeoptim.c done by Ron in [r3542] which somehow got lost in 3.x



libcob:
* common.c (cob_check_fence), common.h: new function to check for writing outside of COBOL data, triggered with compile option -fmemory-check
* statement.def (STMT_BEFORE_CALL, STMT_BEFORE_UDF): new internal statements, currently used for cob_check_fence

additional:
* common.c (b2i): include marker for invalid data (previously not set)

NEWS

@@ -296,6 +296,12 @@ NEWS - user visible changes				-*- outline -*-
    the origin of entrypoints and PERFORM, this is used for the internal
    stack trace on abort and can be used for improved source level debugging
 
+** new flag -fmemory-check (implied with --debug) to do some validation
+   of internal memory used during CALL; this can help in finding otherwise
+   hard to diagnose overwrite of memory and as it is only done on CALL
+   has a much smaller footprint than -fec=bounds (as both check different
+   aspects at different places it is also reasonable to use both)
+
 ** the option -g does no longer imply -fno-remove-unreachable; if you want to
    keep those in you need to explicit specify this
 
@@ -408,6 +414,8 @@ NEWS - user visible changes				-*- outline -*-
    or to use an explicit format (cut at 26 characters, may raise false-positives
    in listing tests) e.g. date only `-DLISTING_TIMESTAMP_FORMAT="%Y-%m-%d"`
 
+** new compile options to adjust the listing, see above
+
 * More notable changes
 
 ** in 64-bit environments, the maximum field size was increased from
@@ -494,6 +502,8 @@ NEWS - user visible changes				-*- outline -*-
     * compile from stdin
   * NIST: OBNC1M.CBL false positive (the test runner uses a nonportable way of
     emulating a program kill)
+  * if build with -fsanitize, then some tests will fail; while we accept patches
+    to improve that, we don't consider the failing tests as bug in GnuCOBOL
 
 ** the recent additions of ">> TURN" and "variable LIKE variable" may not work
    as expected in all cases

cobc/ChangeLog

@@ -1,4 +1,24 @@
 
+2023-07-10  Simon Sobisch <[email protected]>
+
+	check for internal memory bounds with new flag "memory-check"
+	* flag.def, cobc.c (cobc_deciph_memory_check), tree.h: new compile
+	  flag -fmemory-check, implied with --debug
+	* typeck.c (cb_emit_call), tree.h (cb_field): new field attribute
+	  flag_used_in_call
+	* codegen.c (output_local_base_cache, output_nonlocal_base_cache):
+	  generate fencing data fields for fields with flag_used_in_call
+	* codegen.c (output_call_cache): generate fencing data fields for
+	  cob_call_union fields (call pointers)
+	* codegen.c (output_memory_check_call): new function to output
+	  generate fencing data fields for flag_used_in_call
+	* codeoptim.def, codeoptim.c, codegen.c: new entry
+	  COB_CHK_MEMORYFENCE
+
+	additional
+	* codegen.c: only increment/decrement output_indent_level by
+	  indent_adjust_level
+
 2023-07-07  Simon Sobisch <[email protected]>
 
 	common preparser cleanup
@@ -2635,7 +2655,8 @@
 
 	* codeoptim.def (COB_GET_NUMDISPS), codeoptim.c, codegen.c: new routine
 	  to convert signed DISPLAY into binary value;
-	  use of register attribute for cob_get_numdisp + cob_get_numdisps
+	* codeoptim.def (cob_get_numdisp, cob_get_numdisps): use of register
+	  attribute and skipping of leading zeroes
 
 2020-04-23  Simon Sobisch <[email protected]>
 

cobc/cobc.c

@@ -105,6 +105,7 @@ enum compile_level {
 #define	CB_FLAG_GETOPT_NO_DUMP         13
 #define	CB_FLAG_GETOPT_EBCDIC_TABLE    14
 #define	CB_FLAG_GETOPT_DEFAULT_COLSEQ  15
+#define	CB_FLAG_MEMORY_CHECK           16
 
 
 /* Info display limits */
@@ -1954,6 +1955,42 @@ cobc_deciph_optarg (const char *p, const int allow_quote)
 	return (int)n;
 }
 
+/* decipher a value for the memory-check flag,
+   directly setting cb_flag_memory_check,
+   returns -1 on error */
+static int
+cobc_deciph_memory_check (const char *p)
+{
+	char buff[8] = { 0 };
+	const size_t	len = strlen (p);
+	size_t			i;
+
+	if (len > sizeof(buff)) {
+		return -1;
+	}
+	for (i = 0; i < len; ++i) {
+		buff[i] = cb_toupper (p[i]);
+	}
+
+	if (len == 3 && memcmp ("ALL", buff, 3) == 0) {
+		cb_flag_memory_check = CB_MEMCHK_ALL;
+		return 0;
+	}
+	if (len == 4 && memcmp ("NONE", buff, 4) == 0) {
+		cb_flag_memory_check = CB_MEMCHK_NONE;
+		return 0;
+	}
+	if (len == 5 && memcmp ("USING", buff, 5) == 0) {
+		cb_flag_memory_check = CB_MEMCHK_USING;
+		return 0;
+	}
+	if (len == 7 && memcmp ("POINTER", buff, 7) == 0) {
+		cb_flag_memory_check = CB_MEMCHK_POINTER;
+		return 0;
+	}
+	return -1;
+}
+
 /* exit to OS before processing a COBOL/C source file */
 DECLNORET static void COB_A_NORETURN
 cobc_early_exit (int ret_code)
@@ -3231,6 +3268,7 @@ process_command_line (const int argc, char **argv)
 			cb_flag_source_location = 1;
 			cb_flag_stack_extended = 1;
 			cb_flag_stack_check = 1;
+			cb_flag_memory_check = CB_MEMCHK_ALL;
 			cobc_wants_debug = 1;
 			break;
 
@@ -3842,6 +3880,15 @@ process_command_line (const int argc, char **argv)
 			}
 			break;
 
+		case CB_FLAG_MEMORY_CHECK: /* 16 */
+			/* -fmemory-check=<scope> :  */
+			if (!cob_optarg) {
+				cb_flag_memory_check = CB_MEMCHK_ALL;
+			} else if (cobc_deciph_memory_check (cob_optarg)) {
+				cobc_err_exit (COBC_INV_PAR, "-fmemory-check");
+			}
+			break;
+
 		case 'A':
 			/* -A <xx> : Add options to C compile phase */
 			COBC_ADD_STR (cobc_cflags, " ", cob_optarg, NULL);