add docs for assembly and fix global assembly parsing

Previously, global assembly was parsed expecting it to have
the template syntax. However global assembly has no inputs,
outputs, or clobbers, and thus does not have template syntax.
This is now fixed.

This commit also adds a compile error for using volatile
on global assembly, since it is meaningless.

closes #1515

1 files changed, 5 insertions, 111 deletions

diff --git a/src/parser.cpp b/src/parser.cpp
index 1fff47ad9d..104a110f45 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -85,7 +85,7 @@ static AstNode *ast_parse_asm_output(ParseContext *pc);
 static AsmOutput *ast_parse_asm_output_item(ParseContext *pc);
 static AstNode *ast_parse_asm_input(ParseContext *pc);
 static AsmInput *ast_parse_asm_input_item(ParseContext *pc);
-static AstNode *ast_parse_asm_cloppers(ParseContext *pc);
+static AstNode *ast_parse_asm_clobbers(ParseContext *pc);
 static Token *ast_parse_break_label(ParseContext *pc);
 static Token *ast_parse_block_label(ParseContext *pc);
 static AstNode *ast_parse_field_init(ParseContext *pc);
@@ -140,24 +140,6 @@ static void ast_error(ParseContext *pc, Token *token, const char *format, ...) {
     exit(EXIT_FAILURE);
 }
 
-ATTRIBUTE_PRINTF(4, 5)
-ATTRIBUTE_NORETURN
-static void ast_asm_error(ParseContext *pc, AstNode *node, size_t offset, const char *format, ...) {
-    assert(node->type == NodeTypeAsmExpr);
-    va_list ap;
-    va_start(ap, format);
-    Buf *msg = buf_vprintf(format, ap);
-    va_end(ap);
-
-    ErrorMsg *err = err_msg_create_with_line(pc->owner->data.structure.root_struct->path,
-            node->line, node->column,
-            pc->owner->data.structure.root_struct->source_code,
-            pc->owner->data.structure.root_struct->line_offsets, msg);
-
-    print_err_msg(err, pc->err_color);
-    exit(EXIT_FAILURE);
-}
-
 static Buf ast_token_str(Buf *input, Token *token) {
     Buf str = BUF_INIT;
     buf_init_from_mem(&str, buf_ptr(input) + token->start_pos, token->end_pos - token->start_pos);
@@ -486,93 +468,6 @@ AstNode *ast_parse_bin_op_simple(ParseContext *pc) {
     return res;
 }
 
-static void ast_parse_asm_template(ParseContext *pc, AstNode *node) {
-    Buf *asm_template = node->data.asm_expr.asm_template;
-
-    enum State {
-        StateStart,
-        StatePercent,
-        StateTemplate,
-        StateVar,
-    };
-
-    ZigList<AsmToken> *tok_list = &node->data.asm_expr.token_list;
-    assert(tok_list->length == 0);
-
-    AsmToken *cur_tok = nullptr;
-
-    enum State state = StateStart;
-
-    for (size_t i = 0; i < buf_len(asm_template); i += 1) {
-        uint8_t c = *((uint8_t*)buf_ptr(asm_template) + i);
-        switch (state) {
-            case StateStart:
-                if (c == '%') {
-                    tok_list->add_one();
-                    cur_tok = &tok_list->last();
-                    cur_tok->id = AsmTokenIdPercent;
-                    cur_tok->start = i;
-                    state = StatePercent;
-                } else {
-                    tok_list->add_one();
-                    cur_tok = &tok_list->last();
-                    cur_tok->id = AsmTokenIdTemplate;
-                    cur_tok->start = i;
-                    state = StateTemplate;
-                }
-                break;
-            case StatePercent:
-                if (c == '%') {
-                    cur_tok->end = i;
-                    state = StateStart;
-                } else if (c == '[') {
-                    cur_tok->id = AsmTokenIdVar;
-                    state = StateVar;
-                } else if (c == '=') {
-                    cur_tok->id = AsmTokenIdUniqueId;
-                    cur_tok->end = i;
-                    state = StateStart;
-                } else {
-                    ast_asm_error(pc, node, i, "expected a '%%' or '['");
-                }
-                break;
-            case StateTemplate:
-                if (c == '%') {
-                    cur_tok->end = i;
-                    i -= 1;
-                    cur_tok = nullptr;
-                    state = StateStart;
-                }
-                break;
-            case StateVar:
-                if (c == ']') {
-                    cur_tok->end = i;
-                    state = StateStart;
-                } else if ((c >= 'a' && c <= 'z') ||
-                        (c >= '0' && c <= '9') ||
-                        (c == '_'))
-                {
-                    // do nothing
-                } else {
-                    ast_asm_error(pc, node, i, "invalid substitution character: '%c'", c);
-                }
-                break;
-        }
-    }
-
-    switch (state) {
-        case StateStart:
-            break;
-        case StatePercent:
-        case StateVar:
-            ast_asm_error(pc, node, buf_len(asm_template), "unexpected end of assembly template");
-            break;
-        case StateTemplate:
-            cur_tok->end = buf_len(asm_template);
-            break;
-    }
-}
-
 AstNode *ast_parse(Buf *buf, ZigList<Token> *tokens, ZigType *owner, ErrColor err_color) {
     ParseContext pc = {};
     pc.err_color = err_color;
@@ -1931,9 +1826,8 @@ static AstNode *ast_parse_asm_expr(ParseContext *pc) {
 
     res->line = asm_token->start_line;
     res->column = asm_token->start_column;
-    res->data.asm_expr.is_volatile = volatile_token != nullptr;
-    res->data.asm_expr.asm_template = token_buf(asm_template);
-    ast_parse_asm_template(pc, res);
+    res->data.asm_expr.volatile_token = volatile_token;
+    res->data.asm_expr.asm_template = asm_template;
     return res;
 }
 
@@ -1985,7 +1879,7 @@ static AstNode *ast_parse_asm_input(ParseContext *pc) {
         return nullptr;
 
     ZigList<AsmInput *> input_list = ast_parse_list(pc, TokenIdComma, ast_parse_asm_input_item);
-    AstNode *res = ast_parse_asm_cloppers(pc);
+    AstNode *res = ast_parse_asm_clobbers(pc);
     if (res == nullptr)
         res = ast_create_node_no_line_info(pc, NodeTypeAsmExpr);
 
@@ -2013,7 +1907,7 @@ static AsmInput *ast_parse_asm_input_item(ParseContext *pc) {
 }
 
 // AsmClobbers <- COLON StringList
-static AstNode *ast_parse_asm_cloppers(ParseContext *pc) {
+static AstNode *ast_parse_asm_clobbers(ParseContext *pc) {
     if (eat_token_if(pc, TokenIdColon) == nullptr)
         return nullptr;