/* A simple stack-based virtual machine to demonstrate JIT-compilation. Copyright (C) 2014-2017 Free Software Foundation, Inc. This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see . */ #include #include #include #include #include #include #include /* Typedefs. */ typedef struct toyvm_op toyvm_op; typedef struct toyvm_function toyvm_function; typedef struct toyvm_frame toyvm_frame; typedef struct compilation_state compilation_state; typedef struct toyvm_compiled_function toyvm_compiled_function; /* Functions are compiled to this function ptr type. */ typedef int (*toyvm_compiled_code) (int); enum opcode { /* Ops taking no operand. */ DUP, ROT, BINARY_ADD, BINARY_SUBTRACT, BINARY_MULT, BINARY_COMPARE_LT, RECURSE, RETURN, /* Ops taking an operand. */ PUSH_CONST, JUMP_ABS_IF_TRUE }; #define FIRST_UNARY_OPCODE (PUSH_CONST) const char * const opcode_names[] = { "DUP", "ROT", "BINARY_ADD", "BINARY_SUBTRACT", "BINARY_MULT", "BINARY_COMPARE_LT", "RECURSE", "RETURN", "PUSH_CONST", "JUMP_ABS_IF_TRUE", }; struct toyvm_op { /* Which operation. */ enum opcode op_opcode; /* Some opcodes take an argument. */ int op_operand; /* The line number of the operation within the source file. */ int op_linenum; }; #define MAX_OPS (64) struct toyvm_function { const char *fn_filename; int fn_num_ops; toyvm_op fn_ops[MAX_OPS]; }; #define MAX_STACK_DEPTH (8) struct toyvm_frame { toyvm_function *frm_function; int frm_pc; int frm_stack[MAX_STACK_DEPTH]; int frm_cur_depth; }; static void add_op (toyvm_function *fn, enum opcode opcode, int operand, int linenum) { toyvm_op *op; assert (fn->fn_num_ops < MAX_OPS); op = &fn->fn_ops[fn->fn_num_ops++]; op->op_opcode = opcode; op->op_operand = operand; op->op_linenum = linenum; } static void add_unary_op (toyvm_function *fn, enum opcode opcode, const char *rest_of_line, int linenum) { int operand = atoi (rest_of_line); add_op (fn, opcode, operand, linenum); } static char * get_function_name (const char *filename) { /* Skip any path separators. */ const char *pathsep = strrchr (filename, '/'); if (pathsep) filename = pathsep + 1; /* Copy filename to funcname. */ char *funcname = (char *)malloc (strlen (filename) + 1); strcpy (funcname, filename); /* Convert "." to NIL terminator. */ *(strchr (funcname, '.')) = '\0'; return funcname; } static toyvm_function * toyvm_function_parse (const char *filename, const char *name) { FILE *f = NULL; toyvm_function *fn = NULL; char *line = NULL; ssize_t linelen; size_t bufsize; int linenum = 0; assert (filename); assert (name); f = fopen (filename, "r"); if (!f) { fprintf (stderr, "cannot open file %s: %s\n", filename, strerror (errno)); goto error; } fn = (toyvm_function *)calloc (1, sizeof (toyvm_function)); if (!fn) { fprintf (stderr, "out of memory allocating toyvm_function\n"); goto error; } fn->fn_filename = filename; /* Read the lines of the file. */ while ((linelen = getline (&line, &bufsize, f)) != -1) { /* Note that this is a terrible parser, but it avoids the need to bring in lex/yacc as a dependency. */ linenum++; if (0) fprintf (stdout, "%3d: %s", linenum, line); /* Lines beginning with # are comments. */ if (line[0] == '#') continue; /* Skip blank lines. */ if (line[0] == '\n') continue; #define LINE_MATCHES(OPCODE) (0 == strncmp ((OPCODE), line, strlen (OPCODE))) if (LINE_MATCHES ("DUP\n")) add_op (fn, DUP, 0, linenum); else if (LINE_MATCHES ("ROT\n")) add_op (fn, ROT, 0, linenum); else if (LINE_MATCHES ("BINARY_ADD\n")) add_op (fn, BINARY_ADD, 0, linenum); else if (LINE_MATCHES ("BINARY_SUBTRACT\n")) add_op (fn, BINARY_SUBTRACT, 0, linenum); else if (LINE_MATCHES ("BINARY_MULT\n")) add_op (fn, BINARY_MULT, 0, linenum); else if (LINE_MATCHES ("BINARY_COMPARE_LT\n")) add_op (fn, BINARY_COMPARE_LT, 0, linenum); else if (LINE_MATCHES ("RECURSE\n")) add_op (fn, RECURSE, 0, linenum); else if (LINE_MATCHES ("RETURN\n")) add_op (fn, RETURN, 0, linenum); else if (LINE_MATCHES ("PUSH_CONST ")) add_unary_op (fn, PUSH_CONST, line + strlen ("PUSH_CONST "), linenum); else if (LINE_MATCHES ("JUMP_ABS_IF_TRUE ")) add_unary_op (fn, JUMP_ABS_IF_TRUE, line + strlen("JUMP_ABS_IF_TRUE "), linenum); else { fprintf (stderr, "%s:%d: parse error\n", filename, linenum); free (fn); fn = NULL; goto error; } #undef LINE_MATCHES } free (line); fclose (f); return fn; error: free (line); if (f) fclose (f); free (fn); return NULL; } static void toyvm_function_disassemble_op (toyvm_function *fn, toyvm_op *op, int index, FILE *out) { fprintf (out, "%s:%d: index %d: %s", fn->fn_filename, op->op_linenum, index, opcode_names[op->op_opcode]); if (op->op_opcode >= FIRST_UNARY_OPCODE) fprintf (out, " %d", op->op_operand); fprintf (out, "\n"); } static void toyvm_function_disassemble (toyvm_function *fn, FILE *out) { int i; for (i = 0; i < fn->fn_num_ops; i++) { toyvm_op *op = &fn->fn_ops[i]; toyvm_function_disassemble_op (fn, op, i, out); } } static void toyvm_frame_push (toyvm_frame *frame, int arg) { assert (frame->frm_cur_depth < MAX_STACK_DEPTH); frame->frm_stack[frame->frm_cur_depth++] = arg; } static int toyvm_frame_pop (toyvm_frame *frame) { assert (frame->frm_cur_depth > 0); return frame->frm_stack[--frame->frm_cur_depth]; } static void toyvm_frame_dump_stack (toyvm_frame *frame, FILE *out) { int i; fprintf (out, "stack:"); for (i = 0; i < frame->frm_cur_depth; i++) { fprintf (out, " %d", frame->frm_stack[i]); } fprintf (out, "\n"); } /* Execute the given function. */ static int toyvm_function_interpret (toyvm_function *fn, int arg, FILE *trace) { toyvm_frame frame; #define PUSH(ARG) (toyvm_frame_push (&frame, (ARG))) #define POP(ARG) (toyvm_frame_pop (&frame)) frame.frm_function = fn; frame.frm_pc = 0; frame.frm_cur_depth = 0; PUSH (arg); while (1) { toyvm_op *op; int x, y; assert (frame.frm_pc < fn->fn_num_ops); op = &fn->fn_ops[frame.frm_pc++]; if (trace) { toyvm_frame_dump_stack (&frame, trace); toyvm_function_disassemble_op (fn, op, frame.frm_pc, trace); } switch (op->op_opcode) { /* Ops taking no operand. */ case DUP: x = POP (); PUSH (x); PUSH (x); break; case ROT: y = POP (); x = POP (); PUSH (y); PUSH (x); break; case BINARY_ADD: y = POP (); x = POP (); PUSH (x + y); break; case BINARY_SUBTRACT: y = POP (); x = POP (); PUSH (x - y); break; case BINARY_MULT: y = POP (); x = POP (); PUSH (x * y); break; case BINARY_COMPARE_LT: y = POP (); x = POP (); PUSH (x < y); break; case RECURSE: x = POP (); x = toyvm_function_interpret (fn, x, trace); PUSH (x); break; case RETURN: return POP (); /* Ops taking an operand. */ case PUSH_CONST: PUSH (op->op_operand); break; case JUMP_ABS_IF_TRUE: x = POP (); if (x) frame.frm_pc = op->op_operand; break; default: assert (0); /* unknown opcode */ } /* end of switch on opcode */ } /* end of while loop */ #undef PUSH #undef POP } /* JIT compilation. */ struct compilation_state { gcc_jit_context *ctxt; gcc_jit_type *int_type; gcc_jit_type *bool_type; gcc_jit_type *stack_type; /* int[MAX_STACK_DEPTH] */ gcc_jit_rvalue *const_one; gcc_jit_function *fn; gcc_jit_param *param_arg; gcc_jit_lvalue *stack; gcc_jit_lvalue *stack_depth; gcc_jit_lvalue *x; gcc_jit_lvalue *y; gcc_jit_location *op_locs[MAX_OPS]; gcc_jit_block *initial_block; gcc_jit_block *op_blocks[MAX_OPS]; }; /* Stack manipulation. */ static void add_push (compilation_state *state, gcc_jit_block *block, gcc_jit_rvalue *rvalue, gcc_jit_location *loc) { /* stack[stack_depth] = RVALUE */ gcc_jit_block_add_assignment ( block, loc, /* stack[stack_depth] */ gcc_jit_context_new_array_access ( state->ctxt, loc, gcc_jit_lvalue_as_rvalue (state->stack), gcc_jit_lvalue_as_rvalue (state->stack_depth)), rvalue); /* "stack_depth++;". */ gcc_jit_block_add_assignment_op ( block, loc, state->stack_depth, GCC_JIT_BINARY_OP_PLUS, state->const_one); } static void add_pop (compilation_state *state, gcc_jit_block *block, gcc_jit_lvalue *lvalue, gcc_jit_location *loc) { /* "--stack_depth;". */ gcc_jit_block_add_assignment_op ( block, loc, state->stack_depth, GCC_JIT_BINARY_OP_MINUS, state->const_one); /* "LVALUE = stack[stack_depth];". */ gcc_jit_block_add_assignment ( block, loc, lvalue, /* stack[stack_depth] */ gcc_jit_lvalue_as_rvalue ( gcc_jit_context_new_array_access ( state->ctxt, loc, gcc_jit_lvalue_as_rvalue (state->stack), gcc_jit_lvalue_as_rvalue (state->stack_depth)))); } /* A struct to hold the compilation results. */ struct toyvm_compiled_function { gcc_jit_result *cf_jit_result; toyvm_compiled_code cf_code; }; /* The main compilation hook. */ static toyvm_compiled_function * toyvm_function_compile (toyvm_function *fn) { compilation_state state; int pc; char *funcname; memset (&state, 0, sizeof (state)); funcname = get_function_name (fn->fn_filename); state.ctxt = gcc_jit_context_acquire (); gcc_jit_context_set_bool_option (state.ctxt, GCC_JIT_BOOL_OPTION_DUMP_INITIAL_GIMPLE, 0); gcc_jit_context_set_bool_option (state.ctxt, GCC_JIT_BOOL_OPTION_DUMP_GENERATED_CODE, 0); gcc_jit_context_set_int_option (state.ctxt, GCC_JIT_INT_OPTION_OPTIMIZATION_LEVEL, 3); gcc_jit_context_set_bool_option (state.ctxt, GCC_JIT_BOOL_OPTION_KEEP_INTERMEDIATES, 0); gcc_jit_context_set_bool_option (state.ctxt, GCC_JIT_BOOL_OPTION_DUMP_EVERYTHING, 0); gcc_jit_context_set_bool_option (state.ctxt, GCC_JIT_BOOL_OPTION_DEBUGINFO, 1); /* Create types. */ state.int_type = gcc_jit_context_get_type (state.ctxt, GCC_JIT_TYPE_INT); state.bool_type = gcc_jit_context_get_type (state.ctxt, GCC_JIT_TYPE_BOOL); state.stack_type = gcc_jit_context_new_array_type (state.ctxt, NULL, state.int_type, MAX_STACK_DEPTH); /* The constant value 1. */ state.const_one = gcc_jit_context_one (state.ctxt, state.int_type); /* Create locations. */ for (pc = 0; pc < fn->fn_num_ops; pc++) { toyvm_op *op = &fn->fn_ops[pc]; state.op_locs[pc] = gcc_jit_context_new_location (state.ctxt, fn->fn_filename, op->op_linenum, 0); /* column */ } /* Creating the function. */ state.param_arg = gcc_jit_context_new_param (state.ctxt, state.op_locs[0], state.int_type, "arg"); state.fn = gcc_jit_context_new_function (state.ctxt, state.op_locs[0], GCC_JIT_FUNCTION_EXPORTED, state.int_type, funcname, 1, &state.param_arg, 0); /* Create stack lvalues. */ state.stack = gcc_jit_function_new_local (state.fn, NULL, state.stack_type, "stack"); state.stack_depth = gcc_jit_function_new_local (state.fn, NULL, state.int_type, "stack_depth"); state.x = gcc_jit_function_new_local (state.fn, NULL, state.int_type, "x"); state.y = gcc_jit_function_new_local (state.fn, NULL, state.int_type, "y"); /* 1st pass: create blocks, one per opcode. */ /* We need an entry block to do one-time initialization, so create that first. */ state.initial_block = gcc_jit_function_new_block (state.fn, "initial"); /* Create a block per operation. */ for (pc = 0; pc < fn->fn_num_ops; pc++) { char buf[16]; sprintf (buf, "instr%i", pc); state.op_blocks[pc] = gcc_jit_function_new_block (state.fn, buf); } /* Populate the initial block. */ /* "stack_depth = 0;". */ gcc_jit_block_add_assignment ( state.initial_block, state.op_locs[0], state.stack_depth, gcc_jit_context_zero (state.ctxt, state.int_type)); /* "PUSH (arg);". */ add_push (&state, state.initial_block, gcc_jit_param_as_rvalue (state.param_arg), state.op_locs[0]); /* ...and jump to insn 0. */ gcc_jit_block_end_with_jump (state.initial_block, state.op_locs[0], state.op_blocks[0]); /* 2nd pass: fill in instructions. */ for (pc = 0; pc < fn->fn_num_ops; pc++) { gcc_jit_location *loc = state.op_locs[pc]; gcc_jit_block *block = state.op_blocks[pc]; gcc_jit_block *next_block = (pc < fn->fn_num_ops ? state.op_blocks[pc + 1] : NULL); toyvm_op *op; op = &fn->fn_ops[pc]; /* Helper macros. */ #define X_EQUALS_POP()\ add_pop (&state, block, state.x, loc) #define Y_EQUALS_POP()\ add_pop (&state, block, state.y, loc) #define PUSH_RVALUE(RVALUE)\ add_push (&state, block, (RVALUE), loc) #define PUSH_X()\ PUSH_RVALUE (gcc_jit_lvalue_as_rvalue (state.x)) #define PUSH_Y() \ PUSH_RVALUE (gcc_jit_lvalue_as_rvalue (state.y)) gcc_jit_block_add_comment (block, loc, opcode_names[op->op_opcode]); /* Handle the individual opcodes. */ switch (op->op_opcode) { case DUP: X_EQUALS_POP (); PUSH_X (); PUSH_X (); break; case ROT: Y_EQUALS_POP (); X_EQUALS_POP (); PUSH_Y (); PUSH_X (); break; case BINARY_ADD: Y_EQUALS_POP (); X_EQUALS_POP (); PUSH_RVALUE ( gcc_jit_context_new_binary_op ( state.ctxt, loc, GCC_JIT_BINARY_OP_PLUS, state.int_type, gcc_jit_lvalue_as_rvalue (state.x), gcc_jit_lvalue_as_rvalue (state.y))); break; case BINARY_SUBTRACT: Y_EQUALS_POP (); X_EQUALS_POP (); PUSH_RVALUE ( gcc_jit_context_new_binary_op ( state.ctxt, loc, GCC_JIT_BINARY_OP_MINUS, state.int_type, gcc_jit_lvalue_as_rvalue (state.x), gcc_jit_lvalue_as_rvalue (state.y))); break; case BINARY_MULT: Y_EQUALS_POP (); X_EQUALS_POP (); PUSH_RVALUE ( gcc_jit_context_new_binary_op ( state.ctxt, loc, GCC_JIT_BINARY_OP_MULT, state.int_type, gcc_jit_lvalue_as_rvalue (state.x), gcc_jit_lvalue_as_rvalue (state.y))); break; case BINARY_COMPARE_LT: Y_EQUALS_POP (); X_EQUALS_POP (); PUSH_RVALUE ( /* cast of bool to int */ gcc_jit_context_new_cast ( state.ctxt, loc, /* (x < y) as a bool */ gcc_jit_context_new_comparison ( state.ctxt, loc, GCC_JIT_COMPARISON_LT, gcc_jit_lvalue_as_rvalue (state.x), gcc_jit_lvalue_as_rvalue (state.y)), state.int_type)); break; case RECURSE: { X_EQUALS_POP (); gcc_jit_rvalue *arg = gcc_jit_lvalue_as_rvalue (state.x); PUSH_RVALUE ( gcc_jit_context_new_call ( state.ctxt, loc, state.fn, 1, &arg)); break; } case RETURN: X_EQUALS_POP (); gcc_jit_block_end_with_return ( block, loc, gcc_jit_lvalue_as_rvalue (state.x)); break; /* Ops taking an operand. */ case PUSH_CONST: PUSH_RVALUE ( gcc_jit_context_new_rvalue_from_int ( state.ctxt, state.int_type, op->op_operand)); break; case JUMP_ABS_IF_TRUE: X_EQUALS_POP (); gcc_jit_block_end_with_conditional ( block, loc, /* "(bool)x". */ gcc_jit_context_new_cast ( state.ctxt, loc, gcc_jit_lvalue_as_rvalue (state.x), state.bool_type), state.op_blocks[op->op_operand], /* on_true */ next_block); /* on_false */ break; default: assert(0); } /* end of switch on opcode */ /* Go to the next block. */ if (op->op_opcode != JUMP_ABS_IF_TRUE && op->op_opcode != RETURN) gcc_jit_block_end_with_jump ( block, loc, next_block); } /* end of loop on PC locations. */ /* We've now finished populating the context. Compile it. */ gcc_jit_result *jit_result = gcc_jit_context_compile (state.ctxt); gcc_jit_context_release (state.ctxt); toyvm_compiled_function *toyvm_result = (toyvm_compiled_function *)calloc (1, sizeof (toyvm_compiled_function)); if (!toyvm_result) { fprintf (stderr, "out of memory allocating toyvm_compiled_function\n"); gcc_jit_result_release (jit_result); return NULL; } toyvm_result->cf_jit_result = jit_result; toyvm_result->cf_code = (toyvm_compiled_code)gcc_jit_result_get_code (jit_result, funcname); free (funcname); return toyvm_result; } char test[1024]; #define CHECK_NON_NULL(PTR) \ do { \ if ((PTR) != NULL) \ { \ pass ("%s: %s is non-null", test, #PTR); \ } \ else \ { \ fail ("%s: %s is NULL", test, #PTR); \ abort (); \ } \ } while (0) #define CHECK_VALUE(ACTUAL, EXPECTED) \ do { \ if ((ACTUAL) == (EXPECTED)) \ { \ pass ("%s: actual: %s == expected: %s", test, #ACTUAL, #EXPECTED); \ } \ else \ { \ fail ("%s: actual: %s != expected: %s", test, #ACTUAL, #EXPECTED); \ fprintf (stderr, "incorrect value\n"); \ abort (); \ } \ } while (0) static void test_script (const char *scripts_dir, const char *script_name, int input, int expected_result) { char *script_path; toyvm_function *fn; int interpreted_result; toyvm_compiled_function *compiled_fn; toyvm_compiled_code code; int compiled_result; snprintf (test, sizeof (test), "toyvm.c: %s", script_name); script_path = (char *)malloc (strlen (scripts_dir) + strlen (script_name) + 1); CHECK_NON_NULL (script_path); sprintf (script_path, "%s%s", scripts_dir, script_name); fn = toyvm_function_parse (script_path, script_name); CHECK_NON_NULL (fn); interpreted_result = toyvm_function_interpret (fn, input, NULL); CHECK_VALUE (interpreted_result, expected_result); compiled_fn = toyvm_function_compile (fn); CHECK_NON_NULL (compiled_fn); code = (toyvm_compiled_code)compiled_fn->cf_code; CHECK_NON_NULL (code); compiled_result = code (input); CHECK_VALUE (compiled_result, expected_result); gcc_jit_result_release (compiled_fn->cf_jit_result); free (compiled_fn); free (fn); free (script_path); } #define PATH_TO_SCRIPTS ("/jit/docs/examples/tut04-toyvm/") static void test_suite (void) { const char *srcdir; char *scripts_dir; snprintf (test, sizeof (test), "toyvm.c"); /* We need to locate the test scripts. Rely on "srcdir" being set in the environment. */ srcdir = getenv ("srcdir"); CHECK_NON_NULL (srcdir); scripts_dir = (char *)malloc (strlen (srcdir) + strlen(PATH_TO_SCRIPTS) + 1); CHECK_NON_NULL (scripts_dir); sprintf (scripts_dir, "%s%s", srcdir, PATH_TO_SCRIPTS); test_script (scripts_dir, "factorial.toy", 10, 3628800); test_script (scripts_dir, "fibonacci.toy", 10, 55); free (scripts_dir); } int main (int argc, char **argv) { const char *filename = NULL; toyvm_function *fn = NULL; /* If called with no args, assume we're being run by the test suite. */ if (argc < 3) { test_suite (); return 0; } if (argc != 3) { fprintf (stdout, "%s FILENAME INPUT: Parse and run a .toy file\n", argv[0]); exit (1); } filename = argv[1]; fn = toyvm_function_parse (filename, filename); if (!fn) exit (1); if (0) toyvm_function_disassemble (fn, stdout); printf ("interpreter result: %d\n", toyvm_function_interpret (fn, atoi (argv[2]), NULL)); /* JIT-compilation. */ toyvm_compiled_function *compiled_fn = toyvm_function_compile (fn); toyvm_compiled_code code = compiled_fn->cf_code; printf ("compiler result: %d\n", code (atoi (argv[2]))); gcc_jit_result_release (compiled_fn->cf_jit_result); free (compiled_fn); return 0; }