Allow constant initialized globals in advanced code

Use -C const-initializers to enable (or no-const-initializers to disable
in traditional/extended code).

tools/qfcc/doc/man/qfcc.1

@@ -85,7 +85,8 @@ No compilation or linking is done.
 
 .TP
 .B \-\-extended
-Allow extended keywords in traditional mode.
+Allow extended keywords in traditional mode. Otherwise, it has \fIall\fP
+the implications of \fB\-\-traditional\fP.
 
 .TP
 .B \-F, \-\-files
@@ -198,9 +199,9 @@ Look for \*[progs.src] in \fBDIR\fP instead of the current directory.
 .TP
 .B \-\-traditional
 Use traditional QuakeC syntax, semantics and \*(lqbugs\*(rq.
-Also implies the \fBv6only\fP, \fBno-short-circuit\fP and
+Also implies the \fBv6only\fP, \fBno-short-circuit\fP,
-\fBno-local-merging\fP code generation options (see
+\fBconst-initializers\fP and \fBno-local-merging\fP code generation options
-\fBCODE GENERATION OPTIONS\fP).
+(see \fBCODE GENERATION OPTIONS\fP).
 This is the default when using \fBprogs.src\fP mode.
 
 .TP
@@ -236,15 +237,23 @@ command line.
 Unsupported options are ignored.
 The following options are supported by \*[qfcc]'s \fB\-\-code\fP argument:
 
+.TP
+.B const-initializers
+Treat initialized globals as constants.
+This option is implied by \fB\-\-traditional\fP and \fB\-\-extended\fP, and is
+turned off by \fB\-\-advanced\fP.
+
 .TP
 .B cow
 Allow assignment to initialized globals.
-In Quake-C and Ruamoko, a global that has been initialized to a value is not
+When initialized globals are treated as constants (traditional Quake-C, or
-a variable, but a named constant.
+when const-initializers is activated), a global that has been initialized to a
+value is not a variable, but a named constant.
 However, \fBqcc\fP never really enforced this.
 The \fBcow\fP option allows \*[qfcc] to gracefully cope with QuakeC source
 that assigns values to initialized globals in this manner.
-(also known as \*(lqcopy on write\*(rq\(emnever mind the bovine connotations)
+(also known as \*(lqcopy on write\*(rq\(emlo and behold the bovine
+connotations)
 
 .TP
 .B cpp

tools/qfcc/include/options.h

@@ -45,6 +45,7 @@ typedef struct {
 	unsigned    progsversion;		// Progs version to generate code for
 	qboolean    vector_components;	// add *_[xyz] symbols for vectors
 	qboolean    ifstring;			// expand if (str) to if (str != "")
+	qboolean    const_initializers;	// initialied globals are constant
 } code_options_t;
 
 typedef struct {

tools/qfcc/source/def.c

@@ -626,7 +626,7 @@ initialize_def (symbol_t *sym, expr_t *init, defspace_t *space,
 				}
 			}
 			sym->s.def->initialized = 1;
-			if (options.traditional) {
+			if (options.code.const_initializers) {
 				sym->s.def->constant = 1;
 				sym->s.def->nosave = 1;
 			}

tools/qfcc/source/expr.c

@@ -2626,6 +2626,19 @@ cast_expr (type_t *type, expr_t *e)
 		ex_value_t *val = 0;
 		if (e->type == ex_symbol && e->e.symbol->sy_type == sy_const) {
 			val = e->e.symbol->s.value;
+		} else if (e->type == ex_symbol
+				   && e->e.symbol->sy_type == sy_var) {
+			// initialized global def treated as a constant
+			// from the tests above, the def is known to be constant
+			// and of one of the three storable scalar types
+			def_t      *def = e->e.symbol->s.def;
+			if (is_float (def->type)) {
+				val = new_float_val (D_FLOAT (def));
+			} else if (is_double (def->type)) {
+				val = new_double_val (D_DOUBLE (def));
+			} else if (is_integral (def->type)) {
+				val = new_integer_val (D_INT (def));
+			}
 		} else if (e->type == ex_value) {
 			val = e->e.value;
 		} else if (e->type == ex_nil) {

tools/qfcc/source/options.c

@@ -194,12 +194,13 @@ code_usage (void)
 	printf ("%s - QuakeForge Code Compiler\n", this_program);
 	printf ("Code generation options\n");
 	printf (
+"    [no-]const-initializers Treat initialized globals as constants.\n"
 "    [no-]cow                Allow assignment to initialized globals.\n"
 "    [no-]cpp                Preprocess all input files with cpp.\n"
 "    [no-]crc                Write progdefs.h crc to progs.dat.\n"
 "    [no-]debug              Generate debug information.\n"
 "    [no-]fast-float         Use float values directly in \"if\" statements.\n"
-"    help                    Display his text.\n"
+"    help                    Display this text.\n"
 "    [no-]local-merging      Merge the local variable blocks into one.\n"
 "    [no-]optimize           Perform various optimizations on the code.\n"
 "    [no-]short-circuit      Generate short circuit code for logical\n"
@@ -392,16 +393,19 @@ DecodeArgs (int argc, char **argv)
 				options.traditional = 1;
 				options.advanced = false;
 				options.code.progsversion = PROG_ID_VERSION;
+				options.code.const_initializers = true;
 				break;
 			case OPT_TRADITIONAL:
 				options.traditional = 2;
 				options.advanced = false;
 				options.code.progsversion = PROG_ID_VERSION;
+				options.code.const_initializers = true;
 				break;
 			case OPT_ADVANCED:
 				options.traditional = 0;
 				options.advanced = true;
 				options.code.progsversion = PROG_VERSION;
+				options.code.const_initializers = false;
 				break;
 			case OPT_BLOCK_DOT:
 				if (optarg) {
@@ -506,6 +510,8 @@ DecodeArgs (int argc, char **argv)
 								options.code.progsversion = PROG_ID_VERSION;
 							else
 								options.code.progsversion = PROG_VERSION;
+						} else if (!(strcasecmp (temp, "const-initializers"))) {
+							options.code.const_initializers = flag;
 						}
 						temp = strtok (NULL, ",");
 					}