Add symbol info for parameters and local variables

boot/symbol.s

@@ -2,7 +2,9 @@
 # v. 2.0. If a copy of the MPL was not distributed with this file, You can
 # obtain one at https://mozilla.org/MPL/2.0/.
 
-.global symbol_table_build, symbol_table_find, symbol_table_make_pointer
+.global symbol_table
+.global symbol_table_build, symbol_table_find, symbol_table_insert, symbol_table_dump
+.global symbol_table_make_pointer, symbol_table_make_parameter, symbol_table_make_local
 
 .include "boot/definitions.inc"
 
@@ -54,14 +56,51 @@ symbol_table: .zero SYMBOL_PRIME
 
 .section .text
 
+# Prints the list of symbols in the table.
+.type symbol_table_dump, @function
+symbol_table_dump:
+	# Prologue.
+	addi sp, sp, -32
+	sw ra, 28(sp)
+	sw s0, 24(sp)
+	addi s0, sp, 32
+
+	sw s1, 20(sp) # Current symbol in the table.
+	sw s2, 16(sp) # Symbol table length.
+
+	la s1, symbol_table
+	lw s2, 0(s1)
+	addi s1, s1, 4 # Advance to the first symbol in the table.
+
+.Lsymbol_table_dump_loop:
+	beqz s2, .Lsymbol_table_dump_end
+
+	# Compare string lengths.
+	lw a0, 4(s1)
+	lw a1, 0(s1)
+	call _write_error
+
+	addi s1, s1, 12
+	addi s2, s2, -1
+	j .Lsymbol_table_dump_loop
+
+.Lsymbol_table_dump_end:
+	lw s1, 20(sp)
+	lw s2, 16(sp)
+
+	# Epilogue.
+	lw ra, 28(sp)
+	lw s0, 24(sp)
+	addi sp, sp, 32
+	ret
+
 # Searches for a symbol by name.
 #
 # Parameters:
-# a0 - Local symbol table or 0.
-# a1 - Length of the symbol to search.
-# a2 - Pointer to the symbol name.
+# a0 - Length of the symbol to search.
+# a1 - Pointer to the symbol name.
 #
-# Sets a0 to the symbol info.
+# Sets a0 to the symbol info pointer or 0 if the symbol has not been found.
 .type symbol_table_find, @function
 symbol_table_find:
 	# Prologue.
@@ -75,8 +114,8 @@ symbol_table_find:
 	sw s3, 12(sp) # Length of the symbol to search.
 	sw s4, 8(sp) # Pointer to the symbol to search.
 
-	mv s3, a1
-	mv s4, a2
+	mv s3, a0
+	mv s4, a1
 
 	la s1, symbol_table
 	lw s2, 0(s1)
@@ -95,7 +134,7 @@ symbol_table_find:
 	beqz a0, .Lsymbol_table_find_continue
 
 	lw a0, 8(s1) # Pointer to the symbol.
-	j .Lsymbol_table_end
+	j .Lsymbol_table_find_end
 
 .Lsymbol_table_find_continue:
 	addi s1, s1, 12
@@ -105,7 +144,7 @@ symbol_table_find:
 .Lsymbol_table_find_not_found:
 	li a0, 0
 
-.Lsymbol_table_end:
+.Lsymbol_table_find_end:
 	lw s1, 20(sp)
 	lw s2, 16(sp)
 	lw s3, 12(sp)
@@ -133,67 +172,108 @@ symbol_table_make_pointer:
 	li a0, 8
 	ret
 
+# Creates a parameter info.
+#
+# Parameters:
+# a0 - Pointer to the parameter type.
+# a1 - Parameter offset.
+# a2 - Output memory.
+#
+# Sets a0 to the size of newly created info object in bytes.
+.type symbol_table_make_parameter, @function
+symbol_table_make_parameter:
+	li t0, INFO_PARAMETER
+	sw t0, 0(a2)
+	sw a0, 4(a2)
+	sw a1, 8(a2)
+
+	li a0, 12
+	ret
+
+# Creates a local variable info.
+#
+# Parameters:
+# a0 - Pointer to the variable type.
+# a1 - Variable stack offset.
+# a2 - Output memory.
+#
+# Sets a0 to the size of newly created info object in bytes.
+.type symbol_table_make_local, @function
+symbol_table_make_local:
+	li t0, INFO_LOCAL
+	sw t0, 0(a2)
+	sw a0, 4(a2)
+	sw a1, 8(a2)
+
+	li a0, 12
+	ret
+
+# Inserts a symbol into the table.
+#
+# Parameters:
+# a0 - Symbol name length.
+# a1 - Symbol name pointer.
+# a2 - Symbol pointer.
+.type symbol_table_insert, @function
+symbol_table_insert:
+	la t0, symbol_table
+
+	lw t1, 0(t0) # Current table length.
+	li t2, 12 # Calculate the offset to the next entry.
+	mul t2, t1, t2
+	addi t2, t2, 4
+	add t2, t0, t2
+
+	sw a0, 0(t2)
+	sw a1, 4(t2)
+	sw a2, 8(t2)
+
+	addi t1, t1, 1 # Save the new length.
+	sw t1, 0(t0)
+
+	ret
+
 # Build the initial symbols.
 #
 # Sets a0 to the pointer to the global symbol table.
 .type symbol_build, @function
 symbol_table_build:
+	# Prologue.
+	addi sp, sp, -16
+	sw ra, 12(sp)
+	sw s0, 8(sp)
+	addi s0, sp, 16
+
 	la a0, symbol_table
 	addi t0, a0, 4
 
-	li t1, 3 # Length of the word "Int".
-	sw t1, 0(t0)
-	la t1, symbol_builtin_name_int
-	sw t1, 4(t0)
-	la t1, symbol_builtin_type_int
-	sw t1, 8(t0)
-	lw t1, 0(a0)
-	addi t1, t1, 1
-	sw t1, 0(a0)
-	addi t0, t0, 12
+	li a0, 3 # Length of the word "Int".
+	la a1, symbol_builtin_name_int
+	la a2, symbol_builtin_type_int
+	call symbol_table_insert
 
-	li t1, 4 # Length of the word "Word".
-	sw t1, 0(t0)
-	la t1, symbol_builtin_name_word
-	sw t1, 4(t0)
-	la t1, symbol_builtin_type_word
-	sw t1, 8(t0)
-	lw t1, 0(a0)
-	addi t1, t1, 1
-	sw t1, 0(a0)
-	addi t0, t0, 12
+	li a0, 4 # Length of the word "Word".
+	la a1, symbol_builtin_name_word
+	la a2, symbol_builtin_type_word
+	call symbol_table_insert
 
-	li t1, 4 # Length of the word "Byte".
-	sw t1, 0(t0)
-	la t1, symbol_builtin_name_byte
-	sw t1, 4(t0)
-	la t1, symbol_builtin_type_byte
-	sw t1, 8(t0)
-	lw t1, 0(a0)
-	addi t1, t1, 1
-	sw t1, 0(a0)
-	addi t0, t0, 12
+	li a0, 4 # Length of the word "Byte".
+	la a1, symbol_builtin_name_byte
+	la a2, symbol_builtin_type_byte
+	call symbol_table_insert
 
-	li t1, 4 # Length of the word "Char".
-	sw t1, 0(t0)
-	la t1, symbol_builtin_name_char
-	sw t1, 4(t0)
-	la t1, symbol_builtin_type_char
-	sw t1, 8(t0)
-	lw t1, 0(a0)
-	addi t1, t1, 1
-	sw t1, 0(a0)
-	addi t0, t0, 12
+	li a0, 4 # Length of the word "Char".
+	la a1, symbol_builtin_name_char
+	la a2, symbol_builtin_type_char
+	call symbol_table_insert
 
-	li t1, 4 # Length of the word "Bool".
-	sw t1, 0(t0)
-	la t1, symbol_builtin_name_bool
-	sw t1, 4(t0)
-	la t1, symbol_builtin_type_bool
-	sw t1, 8(t0)
-	lw t1, 0(a0)
-	addi t1, t1, 1
-	sw t1, 0(a0)
-	addi t0, t0, 12
+	li a0, 4 # Length of the word "Bool".
+	la a1, symbol_builtin_name_bool
+	la a2, symbol_builtin_type_bool
+	call symbol_table_insert
 
+	# Epilogue.
+	lw ra, 12(sp)
+	lw s0, 8(sp)
+	addi sp, sp, 16
 	ret