in preparation for changing 6g's behavior to

align the output args separately from the input args,
change cgo2c to insert the necessary padding
when the two arg lists are concatenated in the c
translation.

for example, there is a runtime

	func indexstring(s string, i int32) (b byte)

right now in 6g those arguments are aligned in one
struct with s at offset 0, i at 16, and b at 20.
soon the b byte will be in its own struct and structs
are 8 aligned, so it will be b at 24.

right now cgo2c generates:

	void indexstring(string s, int32 i, byte b)

this CL makes it generate, in --6g mode:

	void indexstring(string s, int32 i, uint32, byte b)

this is valid 6c input, although not valid gcc input.
(the code is being generated for 6c only anyway.)

also, allow C code to be mixed in among the Go funcs.
every instance of the token `func' is expected to start
a new go func.

R=iant
DELTA=145  (118 added, 0 deleted, 27 changed)
OCL=30949
CL=30963

src/pkg/runtime/cgo2c.c

@@ -37,6 +37,51 @@ struct params {
 	char *type;
 };
 
+/* index into type_table */
+enum {
+	Bool,
+	Float,
+	Int,
+	Uint,
+	Uintptr,
+	String,
+	Array,
+};
+
+static struct {
+	char *name;
+	int size;
+} type_table[] = {
+	/* variable sized first, for easy replacement */
+	/* order matches enum above */
+	/* default is 32-bit architecture sizes */
+	"bool",		1,
+	"float",	4,
+	"int",		4,
+	"uint",		4,
+	"uintptr",	4,
+	"String",	8,
+	"Array",	12,
+
+	/* fixed size */
+	"float32",	4,
+	"float64",	8,
+	"byte",		1,
+	"int8",		1,
+	"uint8",	1,
+	"int16",	2,
+	"uint16",	2,
+	"int32",	4,
+	"uint32",	4,
+	"int64",	8,
+	"uint64",	8,
+
+	NULL,
+};
+
+/* Fixed structure alignment (non-gcc only) */
+int structround = 4;
+
 /* Unexpected EOF.  */
 static void
 bad_eof(void)
@@ -184,6 +229,8 @@ read_token(void)
 			if (c == EOF)
 				break;
 			if (isspace(c) || strchr(delims, c) != NULL) {
+				if (c == '\n')
+					lineno--;
 				ungetc(c, stdin);
 				break;
 			}
@@ -231,7 +278,7 @@ read_preprocessor_lines(void)
 		} while (isspace(c));
 		if (c != '#') {
 			ungetc(c, stdin);
-			return;
+			break;
 		}
 		putchar(c);
 		do {
@@ -272,24 +319,52 @@ read_type(void)
 	return q;
 }
 
+/* Return the size of the given type. */
+static int
+type_size(char *p)
+{
+	int i;
+
+	if(p[strlen(p)-1] == '*')
+		return type_table[Uintptr].size;
+
+	for(i=0; type_table[i].name; i++)
+		if(strcmp(type_table[i].name, p) == 0)
+			return type_table[i].size;
+	fprintf(stderr, "%s:%u: unknown type %s\n", file, lineno, p);
+	exit(1);
+	return 0;
+}
+
 /* Read a list of parameters.  Each parameter is a name and a type.
    The list ends with a ')'.  We have already read the '('.  */
 static struct params *
-read_params(void)
+read_params(int *poffset)
 {
 	char *token;
-	struct params *ret, **pp;
+	struct params *ret, **pp, *p;
+	int offset, size, rnd;
 
 	ret = NULL;
 	pp = &ret;
 	token = read_token_no_eof();
+	offset = 0;
 	if (strcmp(token, ")") != 0) {
 		while (1) {
-			*pp = xmalloc(sizeof(struct params));
-			(*pp)->name = token;
-			(*pp)->type = read_type();
-			pp = &(*pp)->next;
-			*pp = NULL;
+			p = xmalloc(sizeof(struct params));
+			p->name = token;
+			p->type = read_type();
+			p->next = NULL;
+			*pp = p;
+			pp = &p->next;
+
+			size = type_size(p->type);
+			rnd = size;
+			if(rnd > structround)
+				rnd = structround;
+			if(offset%rnd)
+				offset += rnd - offset%rnd;
+			offset += size;
 
 			token = read_token_no_eof();
 			if (strcmp(token, ",") != 0)
@@ -302,24 +377,39 @@ read_params(void)
 			file, lineno);
 		exit(1);
 	}
+	if (poffset != NULL)
+		*poffset = offset;
 	return ret;
 }
 
 /* Read a function header.  This reads up to and including the initial
    '{' character.  Returns 1 if it read a header, 0 at EOF.  */
 static int
-read_func_header(char **name, struct params **params, struct params **rets)
+read_func_header(char **name, struct params **params, int *paramwid, struct params **rets)
 {
+	int lastline;
 	char *token;
 
-	token = read_token();
-	if (token == NULL)
-		return 0;
-	if (strcmp(token, "func") != 0) {
-		fprintf(stderr, "%s:%u: expected \"func\"\n",
-			file, lineno);
-		exit(1);
+	lastline = -1;
+	while (1) {
+		token = read_token();
+		if (token == NULL)
+			return 0;
+		if (strcmp(token, "func") == 0) {
+			if(lastline != -1)
+				printf("\n");
+			break;
+		}
+		if (lastline != lineno) {
+			if (lastline == lineno-1)
+				printf("\n");
+			else
+				printf("\n#line %d \"%s\"\n", lineno, file);
+			lastline = lineno;
+		}
+		printf("%s ", token);
 	}
+
 	*name = read_token_no_eof();
 
 	token = read_token();
@@ -328,13 +418,13 @@ read_func_header(char **name, struct params **params, struct params **rets)
 			file, lineno);
 		exit(1);
 	}
-	*params = read_params();
+	*params = read_params(paramwid);
 
 	token = read_token();
 	if (token == NULL || strcmp(token, "(") != 0)
 		*rets = NULL;
 	else {
-		*rets = read_params();
+		*rets = read_params(NULL);
 		token = read_token();
 	}
 	if (token == NULL || strcmp(token, "{") != 0) {
@@ -363,13 +453,25 @@ write_params(struct params *params, int *first)
 /* Write a 6g function header.  */
 static void
 write_6g_func_header(char *package, char *name, struct params *params,
-		     struct params *rets)
+		     int paramwid, struct params *rets)
 {
-	int first;
+	int first, n;
 
 	printf("void\n%s·%s(", package, name);
 	first = 1;
 	write_params(params, &first);
+
+	/* insert padding to align output struct */
+	if(rets != NULL && paramwid%structround != 0) {
+		n = structround - paramwid%structround;
+		if(n & 1)
+			printf(", uint8");
+		if(n & 2)
+			printf(", uint16");
+		if(n & 4)
+			printf(", uint32");
+	}
+
 	write_params(rets, &first);
 	printf(")\n{\n");
 }
@@ -456,12 +558,13 @@ write_gcc_func_trailer(char *package, char *name, struct params *rets)
 /* Write out a function header.  */
 static void
 write_func_header(char *package, char *name,
-		  struct params *params, struct params *rets)
+		  struct params *params, int paramwid,
+		  struct params *rets)
 {
 	if (gcc)
 		write_gcc_func_header(package, name, params, rets);
 	else
-		write_6g_func_header(package, name, params, rets);
+		write_6g_func_header(package, name, params, paramwid, rets);
 	printf("#line %d \"%s\"\n", lineno, file);
 }
 
@@ -546,11 +649,12 @@ process_file(void)
 {
 	char *package, *name;
 	struct params *params, *rets;
+	int paramwid;
 
 	package = read_package();
 	read_preprocessor_lines();
-	while (read_func_header(&name, &params, &rets)) {
-		write_func_header(package, name, params, rets);
+	while (read_func_header(&name, &params, &paramwid, &rets)) {
+		write_func_header(package, name, params, paramwid, rets);
 		copy_body();
 		write_func_trailer(package, name, rets);
 		free(name);
@@ -570,6 +674,8 @@ usage(void)
 int
 main(int argc, char **argv)
 {
+	char *goarch;
+
 	while(argc > 1 && argv[1][0] == '-') {
 		if(strcmp(argv[1], "-") == 0)
 			break;
@@ -582,13 +688,13 @@ main(int argc, char **argv)
 		argc--;
 		argv++;
 	}
-	
+
 	if(argc <= 1 || strcmp(argv[1], "-") == 0) {
 		file = "<stdin>";
 		process_file();
 		return 0;
 	}
-	
+
 	if(argc > 2)
 		usage();
 
@@ -597,6 +703,18 @@ main(int argc, char **argv)
 		fprintf(stderr, "open %s: %s\n", file, strerror(errno));
 		exit(1);
 	}
+
+	if(!gcc) {
+		// 6g etc; update size table
+		goarch = getenv("GOARCH");
+		if(goarch != NULL && strcmp(goarch, "amd64") == 0) {
+			type_table[Uintptr].size = 8;
+			type_table[String].size = 16;
+			type_table[Array].size = 8+4+4;
+			structround = 8;
+		}
+	}
+
 	process_file();
 	return 0;
 }