173 lines
4.8 KiB
C
173 lines
4.8 KiB
C
#include <vslc.h>
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#define ASM(opcode, args...) puts("\t"#opcode"\t"#args)
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#define LABEL(label) printf("_%s:\n", (char*)label)
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/**Generate table of strings in a rodata section. */
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void generate_stringtable ( void );
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/**Declare global variables in a bss section */
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void generate_global_variables ( void );
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/**Generate function entry code
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* @param function symbol table entry of function */
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void generate_function ( symbol_t *function );
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/**Generate code for a node in the AST, to be called recursively from
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* generate_function
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* @param node root node of current code block */
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static void generate_node ( node_t *node );
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/**Initializes program (already implemented) */
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void generate_main ( symbol_t *first );
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#define MIN(a,b) (((a)<(b)) ? (a):(b))
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static const char *record[6] = {
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"%rdi", "%rsi", "%rdx", "%rcx", "%r8", "%r9"
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};
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static uint64_t fetch_symbols(tlhash_t* symbol_table, symbol_t*** symbol_list);
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void
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generate_program ( void )
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{
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/* TODO: Emit assembly instructions for functions, function calls,
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* print statements and expressions.
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* The provided function 'generate_main' creates a program entry point
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* for the function symbol it is given as argument.
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*/
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// TODO: Implement
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// - Generate code for all functions
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// - Generate main (function already implemented) by assigning either the
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// function named main or the first function of the source file if no
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// main exists.
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generate_stringtable();
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generate_global_variables();
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symbol_t **global_list;
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uint64_t no_globals = fetch_symbols(global_names, &global_list);
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for (uint64_t g = 0; g < no_globals; g++)
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{
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if (global_list[g]->type == SYM_FUNCTION)
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generate_function(global_list[g]);
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}
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}
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void
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generate_stringtable ( void )
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{
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/* These can be used to emit numbers, strings and a run-time
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* error msg. from main
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*/
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puts("# DATA SECTION");
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puts(".data");
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puts(".intout:\t.asciz \"\%ld \"");
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puts(".strout:\t.asciz \"\%s \"");
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puts(".errout:\t.asciz \"Wrong number of arguments\"");
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for (uint64_t s = 0; s < stringc; s++)
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{
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printf(".STR%03ld:\t.asciz %s\n", s, string_list[s]);
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}
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putchar('\n');
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}
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void
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generate_global_variables ( void )
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{
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symbol_t **global_list;
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uint64_t no_globals = fetch_symbols(global_names, &global_list);
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puts("# GLOBAL VARIABLES");
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puts(".bss");
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puts(".align 8");
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for (uint64_t g = 0; g < no_globals; g++) {
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if (global_list[g]->type == SYM_GLOBAL_VAR)
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printf(".%s:\n", global_list[g]->name);
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}
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putchar('\n');
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free(global_list);
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}
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void
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generate_function ( symbol_t *function )
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{
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// TODO: Generate code for declaring and entering function, then generate its body
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node_t *func_root = function->node;
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LABEL(function->name);
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ASM(pushq, %rbp);
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ASM(movq, %rsp, %rbp);
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putchar('\n');
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}
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void
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generate_node ( node_t *node )
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{
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// TODO: Generate code corresponding to node
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}
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/**Generates the main function with argument parsing and calling of our
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* main function (first, if no function is named main)
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* @param first Symbol table entry of our main function */
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void
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generate_main ( symbol_t *first )
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{
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puts ( ".globl main" );
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puts ( ".section .text" );
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puts ( "main:" );
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puts ( "\tpushq %rbp" );
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puts ( "\tmovq %rsp, %rbp" );
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printf ( "\tsubq\t$1,%%rdi\n" );
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printf ( "\tcmpq\t$%zu,%%rdi\n", first->nparms );
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printf ( "\tjne\tABORT\n" );
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printf ( "\tcmpq\t$0,%%rdi\n" );
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printf ( "\tjz\tSKIP_ARGS\n" );
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printf ( "\tmovq\t%%rdi,%%rcx\n" );
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printf ( "\taddq $%zu, %%rsi\n", 8*first->nparms );
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printf ( "PARSE_ARGV:\n" );
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printf ( "\tpushq %%rcx\n" );
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printf ( "\tpushq %%rsi\n" );
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printf ( "\tmovq\t(%%rsi),%%rdi\n" );
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printf ( "\tmovq\t$0,%%rsi\n" );
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printf ( "\tmovq\t$10,%%rdx\n" );
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printf ( "\tcall\tstrtol\n" );
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/* Now a new argument is an integer in rax */
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printf ( "\tpopq %%rsi\n" );
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printf ( "\tpopq %%rcx\n" );
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printf ( "\tpushq %%rax\n" );
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printf ( "\tsubq $8, %%rsi\n" );
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printf ( "\tloop PARSE_ARGV\n" );
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/* Now the arguments are in order on stack */
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for ( int arg=0; arg<MIN(6,first->nparms); arg++ )
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printf ( "\tpopq\t%s\n", record[arg] );
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printf ( "SKIP_ARGS:\n" );
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printf ( "\tcall\t_%s\n", first->name );
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printf ( "\tjmp\tEND\n" );
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printf ( "ABORT:\n" );
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printf ( "\tmovq\t$.errout, %%rdi\n" );
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printf ( "\tcall puts\n" );
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printf ( "END:\n" );
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puts ( "\tmovq %rax, %rdi" );
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puts ( "\tcall exit" );
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}
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static uint64_t
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fetch_symbols(tlhash_t* symbol_table, symbol_t*** symbol_list)
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{
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uint64_t no_symbols = tlhash_size(symbol_table);
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*symbol_list = malloc(no_symbols * sizeof(symbol_t));
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tlhash_values(symbol_table, (void **)*symbol_list );
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return no_symbols;
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}
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