Add symbol info for parameters and local variables

boot/stage1.s

@@ -85,8 +85,8 @@ source_code: .zero SOURCE_BUFFER_SIZE
 .section .text
 
 # Ignores the import.
-.type _compile_import, @function
-_compile_import:
+.type compile_import, @function
+compile_import:
 	# Prologue.
 	addi sp, sp, -24
 	sw ra, 20(sp)
@@ -227,8 +227,8 @@ compile_binary_expression:
 # a1 - Identifier length.
 #
 # Sets a0 to 1 if the identifier starts with "loca", otherwise to 0.
-.type _is_local_identifier, @function
-_is_local_identifier:
+.type is_local_identifier, @function
+is_local_identifier:
 	# Prologue.
 	addi sp, sp, -16
 	sw ra, 12(sp)
@@ -255,8 +255,8 @@ _is_local_identifier:
 # a1 - Identifier length.
 #
 # Sets a0 to 1 if the identifier is a preserved register, otherwise to 0.
-.type _is_register_identifier, @function
-_is_register_identifier:
+.type is_register_identifier, @function
+is_register_identifier:
 	# Prologue.
 	addi sp, sp, -8
 	sw ra, 4(sp)
@@ -279,8 +279,8 @@ _is_register_identifier:
 # Parameters:
 # a0 - Identifier length.
 # a1 - Register number as character.
-.type _compile_identifier_expression, @function
-_compile_identifier_expression:
+.type compile_identifier_expression, @function
+compile_identifier_expression:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -290,24 +290,32 @@ _compile_identifier_expression:
 	sw a0, 20(sp) # Identifier length.
 	sw a1, 16(sp) # Register number as character.
 
+	lw a0, 20(sp)
+	mv a1, s1
+	call symbol_table_find
+	sw a0, 12(sp)
+
 	mv a0, s1
 	lw a1, 20(sp)
-	call _is_local_identifier
+	call is_local_identifier
 	bnez a0, .Lcompile_identifier_expression_local
 
 	mv a0, s1
 	lw a1, 20(sp)
-	call _is_register_identifier
+	call is_register_identifier
 	bnez a0, .Lcompile_identifier_expression_saved
 
+	lw t0, 12(sp)
+	bnez t0, .Lcompile_identifier_expression_defined
+
 	# Global identifier.
 	lw t1, 16(sp)
 	li t0, 0x00202c00 # \0,_
 	or t0, t0, t1
-	sw t0, 12(sp)
-	li t0, 0x6120616c # la a
 	sw t0, 8(sp)
-	addi a0, sp, 8
+	li t0, 0x6120616c # la a
+	sw t0, 4(sp)
+	addi a0, sp, 4
 	li a1, 7
 	call _write_out
 
@@ -326,26 +334,51 @@ _compile_identifier_expression:
 	li t0, 0x0a290061 # a\0)\n
 	sll t2, t1, 8
 	or t0, t0, t2
-	sw t0, 12(sp)
+	sw t0, 8(sp)
 	li t0, 0x28202c00 # \0, (
 	or t0, t0, t1
+	sw t0, 4(sp)
+	li t0, 0x6120776c # lw a
+	sw t0, 0(sp)
+	addi a0, sp, 0
+	li a1, 12
+	call _write_out
+
+	j .Lcompile_identifier_expression_end
+
+.Lcompile_identifier_expression_defined:
+	lw t1, 16(sp)
+	li t0, 0x00202c00 # \0,_
+	or t0, t0, t1
 	sw t0, 8(sp)
 	li t0, 0x6120776c # lw a
 	sw t0, 4(sp)
 	addi a0, sp, 4
-	li a1, 12
+	li a1, 7
 	call _write_out
 
+	lw a0, 12(sp)
+	lw a0, 8(a0)
+	call _printi
+
+	li t0, 0x29707328 # (sp)
+	sw t0, 8(sp)
+	addi a0, sp, 8
+	li a1, 4
+	call _write_out
+	li a0, '\n'
+	call _put_char
+
 	j .Lcompile_identifier_expression_end
 
 .Lcompile_identifier_expression_saved:
 	li t0, 0x00202c00 # \0,_
 	lw t1, 16(sp)
 	or t0, t0, t1
-	sw t0, 12(sp)
-	li t0, 0x6120766d # mv a
 	sw t0, 8(sp)
-	addi a0, sp, 8
+	li t0, 0x6120766d # mv a
+	sw t0, 4(sp)
+	addi a0, sp, 4
 	li a1, 7
 	call _write_out
 
@@ -362,10 +395,10 @@ _compile_identifier_expression:
 	lw t1, 16(sp)
 	li t0, 0x00202c00 # \0,_
 	or t0, t0, t1
-	sw t0, 12(sp)
-	li t0, 0x6120776c # lw a
 	sw t0, 8(sp)
-	addi a0, sp, 8
+	li t0, 0x6120776c # lw a
+	sw t0, 4(sp)
+	addi a0, sp, 4
 	li a1, 7
 	call _write_out
 
@@ -376,8 +409,8 @@ _compile_identifier_expression:
 	call _write_out
 
 	li t0, 0x29707328 # (sp)
-	sw t0, 12(sp)
-	addi a0, sp, 12
+	sw t0, 8(sp)
+	addi a0, sp, 8
 	li a1, 4
 	call _write_out
 	li a0, '\n'
@@ -431,7 +464,7 @@ _build_expression:
 	lw s1, 32(sp)
 	lw a0, 28(sp)
 	lw a1, 36(sp)
-	call _compile_identifier_expression
+	call compile_identifier_expression
 
 	j .Lbuild_expression_advance
 
@@ -485,7 +518,7 @@ _build_expression:
 
 	lw a0, 32(sp)
 	lw a1, 28(sp)
-	call _compile_call
+	call compile_call
 
 	j .Lbuild_expression_end
 
@@ -524,8 +557,8 @@ _build_expression:
 # Parameters:
 # a0 - Pointer to the identifier.
 # a1 - Identifier length.
-.type _compile_designator_expression, @function
-_compile_designator_expression:
+.type compile_designator_expression, @function
+compile_designator_expression:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -537,12 +570,12 @@ _compile_designator_expression:
 
 	lw a0, 20(sp)
 	lw a1, 16(sp)
-	call _is_local_identifier
+	call is_local_identifier
 	bnez a0, .Lcompile_designator_expression_local
 
 	lw a0, 20(sp)
 	lw a1, 16(sp)
-	call _is_register_identifier
+	call is_register_identifier
 	bnez a0, .Lcompile_designator_expression_saved
 
 .Lcompile_designator_expression_local:
@@ -603,8 +636,8 @@ _compile_designator_expression:
 #
 # Left values should be variables named "loca n", where n is the offset
 # of the variable on the stack, like loca8 or loca4.
-.type _compile_identifier, @function
-_compile_identifier:
+.type compile_identifier, @function
+compile_identifier:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -632,7 +665,7 @@ _compile_identifier:
 .Lcompile_identifier_call:
 	lw a0, 20(sp)
 	lw a1, 16(sp)
-	call _compile_call
+	call compile_call
 
 	j .Lcompile_identifier_end
 
@@ -640,7 +673,7 @@ _compile_identifier:
 	call compile_binary_expression
 	lw a0, 20(sp)
 	lw a1, 16(sp)
-	call _compile_designator_expression
+	call compile_designator_expression
 
 	j .Lcompile_identifier_end
 
@@ -656,8 +689,8 @@ _compile_identifier:
 # a1 - Length of the procedure name.
 #
 # Returns the procedure result in a0.
-.type _compile_call, @function
-_compile_call:
+.type compile_call, @function
+compile_call:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -748,8 +781,8 @@ _compile_call:
 	ret
 
 # Walks through the procedure definitions.
-.type _compile_procedure_section, @function
-_compile_procedure_section:
+.type compile_procedure_section, @function
+compile_procedure_section:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -764,7 +797,7 @@ _compile_procedure_section:
 	lw t1, 4(sp)
 	bne t0, t1, .Lcompile_procedure_section_end
 
-	call _compile_procedure
+	call compile_procedure
 
 	j .Lcompile_procedure_section_loop
 
@@ -775,8 +808,8 @@ _compile_procedure_section:
 	addi sp, sp, 32
 	ret
 
-.type _compile_module_declaration, @function
-_compile_module_declaration:
+.type compile_module_declaration, @function
+compile_module_declaration:
 	# Prologue.
 	addi sp, sp, -24
 	sw ra, 20(sp)
@@ -799,8 +832,8 @@ _compile_module_declaration:
 	addi sp, sp, 24
 	ret
 
-.type _compile_constant_section, @function
-_compile_constant_section:
+.type compile_constant_section, @function
+compile_constant_section:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -830,7 +863,7 @@ _compile_constant_section:
 	bne t0, t1, .Lcompile_constant_section_end
 	lw s1, 20(sp)
 
-	call _compile_constant
+	call compile_constant
 	j .Lcompile_constant_section_item
 
 .Lcompile_constant_section_end:
@@ -840,8 +873,8 @@ _compile_constant_section:
 	addi sp, sp, 32
 	ret
 
-.type _compile_constant, @function
-_compile_constant:
+.type compile_constant, @function
+compile_constant:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -886,8 +919,9 @@ _compile_constant:
 	addi sp, sp, 32
 	ret
 
-.type _compile_variable_section, @function
-_compile_variable_section:
+# Compiles global variable section.
+.type compile_global_section, @function
+compile_global_section:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -899,36 +933,37 @@ _compile_variable_section:
 	call lex_next
 	li t0, TOKEN_VAR
 	lw t1, 4(sp)
-	bne t0, t1, .Lcompile_variable_section_end
+	bne t0, t1, .Lcompile_global_section_end
 	mv s1, a0
 
 	la a0, section_bss
 	li a1, SECTION_BSS_SIZE
 	call _write_out
 
-.Lcompile_variable_section_item:
+.Lcompile_global_section_item:
 	mv a0, s1
 	addi a1, sp, 12
 	call lex_next
+
 	lw t0, 12(sp)
 	li t1, TOKEN_IDENTIFIER
 
-	bne t0, t1, .Lcompile_variable_section_end
+	bne t0, t1, .Lcompile_global_section_end
 	lw s1, 20(sp) # Advance to the beginning of the variable name.
 
-	call _compile_variable
-	j .Lcompile_variable_section_item
+	call compile_global
+	j .Lcompile_global_section_item
 
-.Lcompile_variable_section_end:
+.Lcompile_global_section_end:
 	# Epilogue.
 	lw ra, 28(sp)
 	lw s0, 24(sp)
 	addi sp, sp, 32
 	ret
 
-# Compile a global variable.
-.type _compile_variable, @function
-_compile_variable:
+# Compiles a global variable.
+.type compile_global, @function
+compile_global:
 	# Prologue.
 	addi sp, sp, -48
 	sw ra, 44(sp)
@@ -1010,29 +1045,10 @@ compile_type_expression:
 	beq t0, t1, .Lcompile_type_expression_pointer
 
 	# Named type.
-	mv a0, zero
-	lw a1, 16(sp)
-	lw a2, 20(sp)
+	lw a0, 16(sp)
+	lw a1, 20(sp)
 	call symbol_table_find
 
-	/* DEBUG
-	sw a0, 4(sp)
-
-	lw a0, 4(a0)
-	addi a0, a0, '0'
-	sw a0, 8(sp)
-
-	lw a0, 20(sp)
-	lw a1, 16(sp)
-	call _write_error
-
-	addi a0, sp, 8
-	li a1, 1
-	call _write_error
-
-	lw a0, 4(sp) */
-	/* DEBUG */
-
 	j .Lcompile_type_expression_end
 
 .Lcompile_type_expression_pointer:
@@ -1051,24 +1067,87 @@ compile_type_expression:
 	addi sp, sp, 32
 	ret
 
-.type _compile_parameters, @function
-_compile_parameters:
+# Inserts local procedure variables into the symbol table.
+.type compile_local_section, @function
+compile_local_section:
 	# Prologue.
-	addi sp, sp, -32
-	sw ra, 28(sp)
-	sw s0, 24(sp)
-	addi s0, sp, 32
+	addi sp, sp, -48
+	sw ra, 44(sp)
+	sw s0, 40(sp)
+	addi s0, sp, 48
 
 	mv a0, s1
-	addi a1, sp, 12
+	addi a1, sp, 28
+	call lex_next
+
+	lw t0, 28(sp)
+	li t1, TOKEN_VAR
+
+	bne t0, t1, .Lcompile_local_section_end
+	mv s1, a0
+
+	sw zero, 12(sp) # Variable offset counter.
+
+.Lcompile_local_section_variable:
+	mv a0, s1
+	addi a1, sp, 28
+	call lex_next
+
+	lw t0, 28(sp)
+	li t1, TOKEN_IDENTIFIER
+
+	bne t0, t1, .Lcompile_local_section_end
+	addi a1, sp, 16
+	call lex_next
+	mv s1, a0 # Skip the ":" in front of the type.
+
+	call compile_type_expression
+	# a0 - Variable type.
+	lw a1, 12(sp)
+	mv a2, s3
+	call symbol_table_make_local
+
+	mv a2, s3
+	add s3, s3, a0
+
+	lw a0, 32(sp)
+	lw a1, 36(sp)
+	call symbol_table_insert
+
+	lw t0, 12(sp)
+	addi t0, t0, 4
+	sw t0, 12(sp)
+
+	j .Lcompile_local_section_variable
+
+.Lcompile_local_section_end:
+	# Epilogue.
+	lw ra, 44(sp)
+	lw s0, 40(sp)
+	addi sp, sp, 48
+	ret
+
+# Inserts procedure parameters into the symbol table.
+.type compile_parameters, @function
+compile_parameters:
+	# Prologue.
+	addi sp, sp, -48
+	sw ra, 44(sp)
+	sw s0, 40(sp)
+	addi s0, sp, 48
+
+	sw zero, 12(sp) # Parameter offset counter.
+
+	mv a0, s1
+	addi a1, sp, 28
 	call lex_next
 	mv s1, a0 # Skip the opening paren.
 
 	mv a0, s1
-	addi a1, sp, 12
+	addi a1, sp, 28
 	call lex_next
 
-	lw t0, 12(sp)
+	lw t0, 28(sp)
 	li t1, TOKEN_RIGHT_PAREN
 	beq t0, t1, .Lcompile_parameters_end
 	# When this is not the right paren, it is an identifier.
@@ -1076,21 +1155,37 @@ _compile_parameters:
 
 .Lcompile_parameters_parameter:
 	mv a0, s1
-	addi a1, sp, 0
+	addi a1, sp, 16
 	call lex_next
 	mv s1, a0 # Skip the ":" in front of the type.
 
 	call compile_type_expression
+	# a0 - Parameter type.
+	lw a1, 12(sp)
+	mv a2, s3
+	call symbol_table_make_parameter
+
+	mv a2, s3
+	add s3, s3, a0
+
+	lw a0, 32(sp)
+	lw a1, 36(sp)
+	call symbol_table_insert
+
+	lw t0, 12(sp)
+	addi t0, t0, 4
+	sw t0, 12(sp)
+
 	# Read the comma between the parameters or a closing paren.
 	mv a0, s1
-	addi a1, sp, 0
+	addi a1, sp, 16
 	call lex_next
 
-	lw t0, 0(sp)
+	lw t0, 16(sp)
 	li t1, TOKEN_COMMA
 	bne t0, t1, .Lcompile_parameters_end
 	# If it is a comma, read the name of the next parameter.
-	addi a1, sp, 12
+	addi a1, sp, 16
 	call lex_next
 	mv s1, a0
 
@@ -1100,13 +1195,13 @@ _compile_parameters:
 	mv s1, a0 # Skip the closing paren.
 
 	# Epilogue.
-	lw ra, 28(sp)
-	lw s0, 24(sp)
-	addi sp, sp, 32
+	lw ra, 44(sp)
+	lw s0, 40(sp)
+	addi sp, sp, 48
 	ret
 
-.type _compile_procedure, @function
-_compile_procedure:
+.type compile_procedure, @function
+compile_procedure:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -1124,17 +1219,19 @@ _compile_procedure:
 	lw a1, 20(sp)
 	call _write_procedure_head
 
-	call _compile_parameters
-	# Skip all declarations until we find the "begin" keyword, denoting the
-	# beginning of the procedure body.
-.Lcompile_procedure_begin:
+	# Save the state of the symbol table before we enter the procedure scope.
+	la t0, symbol_table
+	lw t0, (t0)
+	sw t0, 8(sp)
+
+	call compile_parameters
+	call compile_local_section
+
+	# Skip the "begin" keyword, denoting the beginning of the procedure body.
 	mv a0, s1
-	addi a1, sp, 4
+	addi a1, sp, 12
 	call lex_next
 	mv s1, a0
-	lw t0, 4(sp)
-	li t1, TOKEN_BEGIN
-	bne t0, t1, .Lcompile_procedure_begin
 
 	# Generate the procedure prologue with a predefined stack size.
 	la a0, prologue
@@ -1147,7 +1244,7 @@ _compile_procedure:
 	call _write_out
 
 	# Generate the body of the procedure.
-	call _compile_statements
+	call compile_statements
 	mv s1, a0 # Skip end.
 
 	# Generate the procedure epilogue with a predefined stack size.
@@ -1155,6 +1252,24 @@ _compile_procedure:
 	li a1, EPILOGUE_SIZE
 	call _write_out
 
+	/* DEBUG
+	lw a0, 16(sp)
+	lw a1, 20(sp)
+	call symbol_table_find
+	beqz a0, .x
+*/
+	lw a0, 20(sp)
+	lw a1, 16(sp)
+	call _write_error
+
+	call symbol_table_dump
+	/* DEBUG */
+
+	# Restore the symbol table, removing symbols local to this procedure.
+	la t0, symbol_table
+	lw t1, 8(sp)
+	sw t1, (t0)
+
 	# Epilogue.
 	lw ra, 28(sp)
 	lw s0, 24(sp)
@@ -1162,8 +1277,8 @@ _compile_procedure:
 	ret
 
 # Compiles a goto statement to an uncoditional jump.
-.type _compile_goto, @function
-_compile_goto:
+.type compile_goto, @function
+compile_goto:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -1199,8 +1314,8 @@ _compile_goto:
 	ret
 
 # Rewrites a label to assembly.
-.type _compile_label, @function
-_compile_label:
+.type compile_label, @function
+compile_label:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -1231,8 +1346,8 @@ _compile_label:
 	ret
 
 # Just skips the return keyword and evaluates the return expression.
-.type _compile_return, @function
-_compile_return:
+.type compile_return, @function
+compile_return:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -1252,8 +1367,8 @@ _compile_return:
 	addi sp, sp, 32
 	ret
 
-.type _compile_if, @function
-_compile_if:
+.type compile_if, @function
+compile_if:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -1294,7 +1409,7 @@ _compile_if:
 	li a0, '\n'
 	call _put_char
 
-	call _compile_statements
+	call compile_statements
 	mv s1, a0 # Skip end.
 
 	# Write the label prefix.
@@ -1372,8 +1487,8 @@ _write_procedure_head:
 #
 # Sets a0 to the end of the token finishing the list
 # (should be the "end" token in a valid program).
-.type _compile_statements, @function
-_compile_statements:
+.type compile_statements, @function
+compile_statements:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -1390,7 +1505,7 @@ _compile_statements:
 	beq t0, t1, .Lcompile_statements_end
 
 .Lcompile_statements_body:
-	call _compile_statement
+	call compile_statement
 
 	mv a0, s1
 	addi a1, sp, 0
@@ -1411,8 +1526,8 @@ _compile_statements:
 	ret
 
 # Checks for the type of the current statement and compiles it.
-.type _compile_statement, @function
-_compile_statement:
+.type compile_statement, @function
+compile_statement:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -1442,23 +1557,23 @@ _compile_statement:
 	unimp # Else.
 
 .Lcompile_statement_if:
-	call _compile_if
+	call compile_if
 	j .Lcompile_statement_end
 
 .Lcompile_statement_label:
-	call _compile_label
+	call compile_label
 	j .Lcompile_statement_end
 
 .Lcompile_statement_return:
-	call _compile_return
+	call compile_return
 	j .Lcompile_statement_end
 
 .Lcompile_statement_goto:
-	call _compile_goto
+	call compile_goto
 	j .Lcompile_statement_end
 
 .Lcompile_statement_identifier:
-	call _compile_identifier
+	call compile_identifier
 	j .Lcompile_statement_end
 
 .Lcompile_statement_end:
@@ -1469,8 +1584,8 @@ _compile_statement:
 	ret
 
 # Prints ".section .text" and exits.
-.type _compile_text_section, @function
-_compile_text_section:
+.type compile_text_section, @function
+compile_text_section:
 	# Prologue.
 	addi sp, sp, -16
 	sw ra, 12(sp)
@@ -1487,8 +1602,8 @@ _compile_text_section:
 	addi sp, sp, 16
 	ret
 
-.type _compile_entry_point, @function
-_compile_entry_point:
+.type compile_entry_point, @function
+compile_entry_point:
 	# Prologue.
 	addi sp, sp, -32
 	sw ra, 28(sp)
@@ -1506,7 +1621,7 @@ _compile_entry_point:
 	mv s1, a0 # Skip begin.
 
 	# Generate the body of the procedure.
-	call _compile_statements
+	call compile_statements
 	mv s1, a0 # Skip end.
 
 	la a0, asm_exit
@@ -1519,21 +1634,21 @@ _compile_entry_point:
 	addi sp, sp, 32
 	ret
 
-.type _compile, @function
-_compile:
+.type compile, @function
+compile:
 	# Prologue.
 	addi sp, sp, -16
 	sw ra, 12(sp)
 	sw s0, 8(sp)
 	addi s0, sp, 16
 
-	call _compile_module_declaration
-	call _compile_import
-	call _compile_constant_section
-	call _compile_variable_section
-	call _compile_text_section
-	call _compile_procedure_section
-	call _compile_entry_point
+	call compile_module_declaration
+	call compile_import
+	call compile_constant_section
+	call compile_global_section
+	call compile_text_section
+	call compile_procedure_section
+	call compile_entry_point
 
 	# Epilogue.
 	lw ra, 12(sp)
@@ -1554,7 +1669,7 @@ _start:
 	mv s3, a0
 
 	call symbol_table_build
-	call _compile
+	call compile
 
 	# Call exit.
 	li a0, 0   # Use 0 return code.