parser, cgen: fix basic asm registers, fix numbered labels in addressing, support indirect branching (#10545)

cmd/tools/vast/vast.v

@@ -1775,7 +1775,7 @@ fn (t Tree) asm_stmt(node ast.AsmStmt) &Node {
 	mut obj := new_object()
 	obj.add('ast_type', t.string_node('AsmStmt'))
 	obj.add('arch', t.enum_node(node.arch))
-	obj.add('is_top_level', t.bool_node(node.is_top_level))
+	obj.add('is_basic', t.bool_node(node.is_basic))
 	obj.add('is_volatile', t.bool_node(node.is_volatile))
 	obj.add('is_goto', t.bool_node(node.is_goto))
 	obj.add('scope', t.scope(node.scope))

vlib/v/ast/ast.v

@@ -1106,12 +1106,12 @@ pub mut:
 
 pub struct AsmStmt {
 pub:
-	arch         pref.Arch
-	is_top_level bool
-	is_volatile  bool
-	is_goto      bool
-	clobbered    []AsmClobbered
-	pos          token.Position
+	arch        pref.Arch
+	is_basic    bool
+	is_volatile bool
+	is_goto     bool
+	clobbered   []AsmClobbered
+	pos         token.Position
 pub mut:
 	templates     []AsmTemplate
 	scope         &Scope

vlib/v/fmt/fmt.v

@@ -730,7 +730,7 @@ fn (mut f Fmt) asm_stmt(stmt ast.AsmStmt) {
 	}
 	f.indent--
 	f.writeln('}')
-	if stmt.is_top_level {
+	if f.indent == 0 {
 		f.writeln('')
 	}
 }
@@ -801,7 +801,13 @@ fn (mut f Fmt) asm_arg(arg ast.AsmArg) {
 			f.write(']')
 		}
 		ast.AsmDisp {
-			f.write(arg.val)
+			if arg.val.len >= 2 && arg.val[arg.val.len - 1] in [`b`, `f`]
+				&& arg.val[..arg.val.len - 1].bytes().all(it.is_digit()) {
+				f.write(arg.val[arg.val.len - 1].ascii_str())
+				f.write(arg.val[..arg.val.len - 1])
+			} else {
+				f.write(arg.val)
+			}
 		}
 	}
 }

vlib/v/gen/c/cgen.v

@@ -1955,6 +1955,11 @@ fn (mut g Gen) gen_asm_stmt(stmt ast.AsmStmt) {
 		}
 
 		for i, arg in template.args {
+			if stmt.arch == .amd64 && (template.name == 'call' || template.name[0] == `j`)
+				&& arg is ast.AsmRegister {
+				g.write('*') // indirect branching
+			}
+
 			g.asm_arg(arg, stmt)
 			if i + 1 < template.args.len {
 				g.write(', ')
@@ -1966,6 +1971,7 @@ fn (mut g Gen) gen_asm_stmt(stmt ast.AsmStmt) {
 		}
 		g.writeln('"')
 	}
+
 	if stmt.output.len != 0 || stmt.input.len != 0 || stmt.clobbered.len != 0 || stmt.is_goto {
 		g.write(': ')
 	}
@@ -2007,7 +2013,7 @@ fn (mut g Gen) asm_arg(arg ast.AsmArg, stmt ast.AsmStmt) {
 		ast.AsmAlias {
 			name := arg.name
 			if name in stmt.local_labels || name in stmt.global_labels
-				|| name in g.file.global_labels || stmt.is_top_level
+				|| name in g.file.global_labels || stmt.is_basic
 				|| (name !in stmt.input.map(it.alias) && name !in stmt.output.map(it.alias)) {
 				asm_formatted_name := if name in stmt.global_labels { '%l[$name]' } else { name }
 				g.write(asm_formatted_name)
@@ -2025,8 +2031,8 @@ fn (mut g Gen) asm_arg(arg ast.AsmArg, stmt ast.AsmStmt) {
 			g.write('\$$arg.val.str()')
 		}
 		ast.AsmRegister {
-			if !stmt.is_top_level {
-				g.write('%') // escape percent in extended assembly
+			if !stmt.is_basic {
+				g.write('%') // escape percent with percent in extended assembly
 			}
 			g.write('%$arg.name')
 		}
@@ -2093,25 +2099,10 @@ fn (mut g Gen) asm_arg(arg ast.AsmArg, stmt ast.AsmStmt) {
 			}
 		}
 		ast.AsmDisp {
-			if arg.val.len >= 2 && arg.val[0] in [`b`, `f`] {
-				mut is_digit := true
-				for c in arg.val[1..] {
-					if !c.is_digit() {
-						is_digit = false
-						break
-					}
-				}
-				if is_digit {
-					g.write(arg.val[1..] + rune(arg.val[0]).str())
-				} else {
-					g.write(arg.val)
-				}
-			} else {
-				g.write(arg.val)
-			}
+			g.write(arg.val)
 		}
 		string {
-			g.write('$arg')
+			g.write(arg)
 		}
 	}
 }

vlib/v/parser/parser.v

@@ -931,27 +931,7 @@ fn (mut p Parser) asm_stmt(is_top_level bool) ast.AsmStmt {
 				}
 				match p.tok.kind {
 					.name {
-						if p.tok.kind == .name && p.tok.lit.len >= 2
-							&& (p.tok.lit.starts_with('b') || p.tok.lit.starts_with('f')) {
-							mut is_digit := true
-							for c in p.tok.lit[1..] {
-								if !c.is_digit() {
-									is_digit = false
-									break
-								}
-							}
-							if is_digit {
-								args << ast.AsmDisp{
-									val: p.tok.lit
-									pos: p.tok.position()
-								}
-								p.check(.name)
-							} else {
-								args << p.reg_or_alias()
-							}
-						} else {
-							args << p.reg_or_alias()
-						}
+						args << p.reg_or_alias()
 					}
 					.number {
 						number_lit := p.parse_number_literal()
@@ -962,9 +942,7 @@ fn (mut p Parser) asm_stmt(is_top_level bool) ast.AsmStmt {
 								}
 							}
 							ast.IntegerLiteral {
-								if (is_directive || number_lit.val.ends_with('b')
-									|| number_lit.val.ends_with('f'))
-									&& !number_lit.val.starts_with('0x') {
+								if is_directive {
 									args << ast.AsmDisp{
 										val: number_lit.val
 										pos: number_lit.pos
@@ -1099,7 +1077,7 @@ fn (mut p Parser) asm_stmt(is_top_level bool) ast.AsmStmt {
 		input: input
 		clobbered: clobbered
 		pos: pos.extend(p.tok.position())
-		is_top_level: is_top_level
+		is_basic: is_top_level || output.len + input.len + clobbered.len == 0
 		scope: scope
 		global_labels: global_labels
 		local_labels: local_labels
@@ -1107,18 +1085,21 @@ fn (mut p Parser) asm_stmt(is_top_level bool) ast.AsmStmt {
 }
 
 fn (mut p Parser) reg_or_alias() ast.AsmArg {
-	if p.tok.lit in p.scope.objects {
-		x := p.scope.objects[p.tok.lit]
+	p.check(.name)
+	if p.prev_tok.lit in p.scope.objects {
+		x := p.scope.objects[p.prev_tok.lit]
 		if x is ast.AsmRegister {
-			b := x
-			p.check(.name)
-			return b
+			return ast.AsmArg(x as ast.AsmRegister)
 		} else {
-			verror('parser bug: non-register ast.ScopeObject found in scope')
+			verror('non-register ast.ScopeObject found in scope')
 			return ast.AsmDisp{} // should not be reached
 		}
+	} else if p.prev_tok.len >= 2 && p.prev_tok.lit[0] in [`b`, `f`]
+		&& p.prev_tok.lit[1..].bytes().all(it.is_digit()) {
+		return ast.AsmDisp{
+			val: p.prev_tok.lit[1..] + p.prev_tok.lit[0].ascii_str()
+		}
 	} else {
-		p.check(.name)
 		return ast.AsmAlias{
 			name: p.prev_tok.lit
 			pos: p.prev_tok.position()
@@ -1215,11 +1196,12 @@ fn (mut p Parser) reg_or_alias() ast.AsmArg {
 // 		pos: pos.extend(p.prev_tok.position())
 // 	}
 // }
+
 fn (mut p Parser) asm_addressing() ast.AsmAddressing {
 	pos := p.tok.position()
 	p.check(.lsbr)
 	unknown_addressing_mode := 'unknown addressing mode. supported ones are [displacement],	[base], [base + displacement], [index ∗ scale + displacement], [base + index ∗ scale + displacement], [base + index + displacement], [rip + displacement]'
-	// this mess used to look much cleaner before the removal of peek_tok3, see above
+	// this mess used to look much cleaner before the removal of peek_tok2/3, see above code for cleaner version
 	if p.peek_tok.kind == .rsbr { // [displacement] or [base]
 		if p.tok.kind == .name {
 			base := p.reg_or_alias()