Begin work on asm label support.

src/compiler/codegen_asm.c

@@ -7,6 +7,13 @@
 #define CAST_AND_EXTEND(x, n) \
     (((int64_t)((x) << (64 - (n)))) >> (64 - (n)))
 
+INLINE bool codegen_asm_label(Ast *ast)
+{
+	if (ast->ast_kind != AST_ASM_LABEL) return false;
+	scratch_buffer_printf("${:private}%s.${:uid}:\n", ast->asm_label);
+	return true;
+}
+
 static inline void codegen_create_x86att_arg(AsmInlineBlock *block, unsigned input_offset, Expr *expr)
 {
 	ExprAsmArg *arg = &expr->expr_asm_arg;
@@ -177,6 +184,7 @@ static inline char *codegen_create_x86_att_asm(AsmInlineBlock *block)
 	{
 		Ast *ast = astptr(next);
 		next = ast->next;
+		if (codegen_asm_label(ast)) continue;
 		scratch_buffer_append(ast->asm_stmt.instruction);
 		Expr** args = ast->asm_stmt.args;
 		unsigned arg_count = vec_size(args);
@@ -201,6 +209,7 @@ static inline char *codegen_create_aarch64_asm(AsmInlineBlock *block)
 	{
 		Ast *ast = astptr(next);
 		next = ast->next;
+		if (codegen_asm_label(ast)) continue;
 		scratch_buffer_append(ast->asm_stmt.instruction);
 		Expr** args = ast->asm_stmt.args;
 		unsigned arg_count = vec_size(args);
@@ -225,6 +234,7 @@ static inline char *codegen_create_riscv_asm(AsmInlineBlock *block)
 	{
 		Ast *ast = astptr(next);
 		next = ast->next;
+		if (codegen_asm_label(ast)) continue;
 		scratch_buffer_append(ast->asm_stmt.instruction);
 		Expr** args = ast->asm_stmt.args;
 		unsigned arg_count = vec_size(args);

src/compiler/compiler_internal.h

@@ -1376,8 +1376,8 @@ typedef struct
 typedef struct
 {
 	Clobbers clobbers;
-	const char *asm_block;
 	AstId asm_stmt;
+	Ast **labels;
 	ExprAsmArg **output_vars;
 	ExprAsmArg **input;
 } AsmInlineBlock;
@@ -1454,8 +1454,10 @@ typedef struct Ast_
 	union
 	{
 		FlowCommon flow;                    // Shared struct
+
 		AstAsmBlock asm_block_stmt;
 		AstAsmStmt asm_stmt;
+		const char *asm_label;
 		AstAssertStmt assert_stmt;          // 16
 		AstCaseStmt case_stmt;              // 32
 		AstCompoundStmt compound_stmt;      // 12

src/compiler/copying.c

@@ -727,6 +727,7 @@ Ast *ast_copy_deep(CopyStruct *c, Ast *source)
 			MACRO_COPY_EXPRID(ast->nextcase_stmt.expr);
 			break;
 		case AST_NOP_STMT:
+		case AST_ASM_LABEL:
 			break;
 		case AST_BLOCK_EXIT_STMT:
 		case AST_RETURN_STMT:

src/compiler/enums.h

@@ -188,6 +188,7 @@ typedef enum
 	AST_POISONED,
 	AST_ASM_STMT,
 	AST_ASM_BLOCK_STMT,
+	AST_ASM_LABEL,
 	AST_ASSERT_STMT,
 	AST_BREAK_STMT,
 	AST_CASE_STMT,

src/compiler/llvm_codegen_stmt.c

@@ -1612,6 +1612,7 @@ void llvm_emit_stmt(GenContext *c, Ast *ast)
 		case AST_FOREACH_STMT:
 		case AST_CONTRACT:
 		case AST_ASM_STMT:
+		case AST_ASM_LABEL:
 		case AST_CONTRACT_FAULT:
 		case AST_CASE_STMT:
 		case AST_DEFAULT_STMT:

src/compiler/parse_stmt.c

@@ -380,6 +380,14 @@ static inline Expr *parse_asm_expr(ParseContext *c)
 static inline Ast *parse_asm_stmt(ParseContext *c)
 {
 	Ast *asm_stmt = ast_new_curr(c, AST_ASM_STMT);
+	if (tok_is(c, TOKEN_CONST_IDENT))
+	{
+		asm_stmt->asm_label = symstr(c);
+		advance_and_verify(c, TOKEN_CONST_IDENT);
+		asm_stmt->ast_kind = AST_ASM_LABEL;
+		TRY_CONSUME_OR_RET(TOKEN_COLON, "Expected a ':' to terminate the label.", poisoned_ast);
+		return asm_stmt;
+	}
 	if (!tok_is(c, TOKEN_IDENT) && !tok_is(c, TOKEN_INT))
 	{
 		PRINT_ERROR_HERE("Expected an asm instruction here.");

src/compiler/sema_asm.c

@@ -184,8 +184,7 @@ static inline bool sema_check_asm_arg_addr(SemaContext *context, AsmInlineBlock
 {
 	if (!arg_type.is_address)
 	{
-		SEMA_ERROR(expr, "An address cannot appear in this slot.");
-		return false;
+		RETURN_SEMA_ERROR(expr, "An address cannot appear in this slot.");
 	}
 	ExprAsmArg *asm_arg = &expr->expr_asm_arg;
 	Expr *base = exprptr(asm_arg->base);
@@ -207,8 +206,7 @@ static inline bool sema_check_asm_arg_addr(SemaContext *context, AsmInlineBlock
 			TODO
 			break;
 		default:
-			SEMA_ERROR(expr, "Expected a register here.");
-			return false;
+			RETURN_SEMA_ERROR(expr, "Expected a register here.");
 	}
 	Expr *index = exprptrzero(asm_arg->idx);
 
@@ -232,8 +230,7 @@ static inline bool sema_check_asm_arg_addr(SemaContext *context, AsmInlineBlock
 		}
 		if (bit_size != index_size)
 		{
-			SEMA_ERROR(index, "Expected the same register size as for the base value.");
-			return false;
+			RETURN_SEMA_ERROR(index, "Expected the same register size as for the base value.");
 		}
 	}
 	if ((compiler.platform.arch == ARCH_TYPE_RISCV32 || 
@@ -243,8 +240,7 @@ static inline bool sema_check_asm_arg_addr(SemaContext *context, AsmInlineBlock
 		if ((asm_arg->neg_offset && asm_arg->offset > abs(INT12_MIN)) ||
 			(!asm_arg->neg_offset && asm_arg->offset > INT12_MAX))
 		{
-			SEMA_ERROR(expr, "RISC-V offset limited to 12-bits signed.");
-			return false;
+			RETURN_SEMA_ERROR(expr, "RISC-V offset limited to 12-bits signed.");
 		}
 	}
 
@@ -256,15 +252,10 @@ static inline bool sema_check_asm_arg_reg(SemaContext *context, AsmInlineBlock *
 {
 	const char *name = expr->expr_asm_arg.reg.name;
 	AsmRegister *reg = expr->expr_asm_arg.reg.ref = asm_reg_by_name(&compiler.platform, name);
-	if (!reg)
-	{
-		SEMA_ERROR(expr, "Expected a valid register name.");
-		return false;
-	}
+	if (!reg) RETURN_SEMA_ERROR(expr, "Expected a valid register name.");
 	if (!sema_reg_is_valid_in_slot(reg, arg_type))
 	{
-		SEMA_ERROR(expr, "'%s' is not valid in this slot.", reg->name);
-		return false;
+		RETURN_SEMA_ERROR(expr, "'%s' is not valid in this slot.", reg->name);
 	}
 	if (arg_type.is_write)
 	{

src/compiler/sema_decls.c

@@ -3700,6 +3700,7 @@ static inline bool sema_analyse_macro(SemaContext *context, Decl *decl, bool *er
 					continue;
 				case AST_POISONED:
 				case AST_ASM_STMT:
+				case AST_ASM_LABEL:
 				case AST_ASM_BLOCK_STMT:
 				case AST_ASSERT_STMT:
 				case AST_BREAK_STMT:

src/compiler/sema_liveness.c

@@ -111,6 +111,7 @@ static void sema_trace_stmt_liveness(Ast *ast)
 			sema_trace_stmt_liveness(astptr(ast->defer_stmt.body));
 			return;
 		case AST_NOP_STMT:
+		case AST_ASM_LABEL:
 			return;
 		case AST_COMPOUND_STMT:
 			sema_trace_stmt_chain_liveness(ast->compound_stmt.first_stmt);

src/compiler/sema_stmts.c

@@ -51,6 +51,22 @@ static bool sema_analyse_require(SemaContext *context, Ast *directive, AstId **a
 static bool sema_analyse_ensure(SemaContext *context, Ast *directive);
 static bool sema_analyse_optional_returns(SemaContext *context, Ast *directive);
 
+static inline bool sema_analyse_asm_label(SemaContext *context, AsmInlineBlock *block, Ast *label)
+{
+	const char *name = label->asm_label;
+	FOREACH(Ast *, other, block->labels)
+	{
+		if (name == other->asm_label)
+		{
+			SEMA_ERROR(label, "Duplicate ASM label '%s'.", name);
+			SEMA_NOTE(other, "The previous definition was here.");
+			return false;
+		}
+	}
+	vec_add(block->labels, label);
+	return true;
+}
+
 static inline bool sema_analyse_asm_stmt(SemaContext *context, Ast *stmt)
 {
 	if (stmt->asm_block_stmt.is_string) return sema_analyse_asm_string_stmt(context, stmt);
@@ -68,6 +84,11 @@ static inline bool sema_analyse_asm_stmt(SemaContext *context, Ast *stmt)
 	{
 		Ast *ast = astptr(ast_id);
 		ast_id = ast->next;
+		if (ast->ast_kind == AST_ASM_LABEL)
+		{
+			sema_analyse_asm_label(context, block, ast);
+			continue;
+		}
 		if (!sema_analyse_asm(context, block, ast)) return false;
 	}
 	return true;
@@ -2910,6 +2931,7 @@ static inline bool sema_analyse_statement_inner(SemaContext *context, Ast *state
 		case AST_IF_CATCH_SWITCH_STMT:
 		case AST_CONTRACT:
 		case AST_ASM_STMT:
+		case AST_ASM_LABEL:
 		case AST_CONTRACT_FAULT:
 			UNREACHABLE
 		case AST_DECLS_STMT: