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janet/core/asm.c
bakpakin f6dcb07c8d More work. Too many changes to be listed.
2017-11-05 22:05:47 -05:00

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/*
* Copyright (c) 2017 Calvin Rose
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include <setjmp.h>
#include <dst/dst.h>
/* Bytecode op argument types */
/* s - a slot */
/* c - a constant */
/* i - a small integer */
/* t - a type (have a simple type for non unions) */
/* l - a label */
typedef enum DstOpArgType DstOpArgType;
enum DstOpArgType {
DST_OAT_SLOT,
DST_OAT_ENVIRONMENT,
DST_OAT_CONSTANT,
DST_OAT_INTEGER,
DST_OAT_TYPE,
DST_OAT_SIMPLETYPE,
DST_OAT_LABEL
};
/* Convert a slot to to an integer for bytecode */
/* Types of instructions */
/* _0arg - op.---.--.-- (return-nil, noop, vararg arguments)
* _s - op.src.--.-- (push1)
* _l - op.XX.XX.XX (jump)
* _ss - op.dest.XX.XX (move, swap)
* _sl - op.check.XX.XX (jump-if)
* _st - op.check.TT.TT (typecheck)
* _si - op.dest.XX.XX (load-integer)
* _sss - op.dest.op1.op2 (add, subtract, arithmetic, comparison)
* _ses - op.dest.up.which (load-upvalue, save-upvalue)
* _sc - op.dest.CC.CC (load-constant, closure)
*/
/* Various types of instructions */
typedef enum DstInstructionType DstInstructionType;
enum DstInstructionType {
DIT_0, /* No args */
DIT_S, /* One slot */
DIT_L, /* One label */
DIT_SS, /* Two slots */
DIT_SL,
DIT_ST,
DIT_SI,
DIT_SU, /* Unsigned */
DIT_SSS,
DIT_SES,
DIT_SC
};
/* Definition for an instruction in the assembler */
typedef struct DstInstructionDef DstInstructionDef;
struct DstInstructionDef {
const char *name;
DstInstructionType type;
uint8_t opcode;
};
/* Hold all state needed during assembly */
typedef struct DstAssembler DstAssembler;
struct DstAssembler {
DstAssembler *parent;
DstFuncDef *def;
jmp_buf on_error;
const char *errmessage;
uint32_t environments_capacity;
uint32_t bytecode_count; /* Used for calculating labels */
DstTable labels; /* symbol -> bytecode index */
DstTable constants; /* symbol -> constant index */
DstTable slots; /* symbol -> slot index */
DstTable envs; /* symbol -> environment index */
};
/* Dst opcode descriptions in lexographic order. This
* allows a binary search over the elements to find the
* correct opcode given a name. This works in reasonable
* time and is easier to setup statically than a hash table or
* prefix tree. */
static const DstInstructionDef dst_ops[] = {
{"add", DIT_SSS, 0x01},
{"bitand", DIT_SSS, 0x02},
{"bitor", DIT_SSS, 0x03},
{"bitxor", DIT_SSS, 0x04},
{"call", DIT_SS, 0x05},
{"closure", DIT_SC, 0x06},
{"divide", DIT_SSS, 0x07},
{"jump", DIT_L, 0x08},
{"jump-if", DIT_SL, 0x09},
{"load-constant", DIT_SC, 0x0A},
{"load-false", DIT_S, 0x0B},
{"load-integer", DIT_SI, 0x0C},
{"load-nil", DIT_S, 0x0D},
{"load-true", DIT_S, 0x0E},
{"load-upvalue", DIT_SES, 0x0F},
{"move", DIT_SS, 0x10},
{"modulo", DIT_SSS, 0x11},
{"multiply", DIT_SSS, 0x12},
{"noop", DIT_0, 0x00},
{"push", DIT_S, 0x13},
{"push2", DIT_SS, 0x14},
{"push3", DIT_SSS, 0x15},
{"push-array", DIT_S, 0x16},
{"return", DIT_S, 0x19},
{"return-nil", DIT_0, 0x1A},
{"save-upvalue", DIT_SES, 0x1B},
{"shift-left", DIT_SSS, 0x1C},
{"shift-right", DIT_SSS, 0x1D},
{"shift-right-signed", DIT_SSS, 0x1E},
{"subtract", DIT_SSS, 0x1F},
{"syscall", DIT_SU, 0x21},
{"tailcall", DIT_S, 0x22},
{"transfer", DIT_SSS, 0x23},
{"typecheck", DIT_ST, 0x24},
};
/* Compare a DST string to a native 0 terminated c string. Used in the
* binary search for the instruction definition. */
static int dst_strcompare(const uint8_t *str, const char *other) {
uint32_t len = dst_string_length(str);
uint32_t index;
for (index = 0; index < len; index++) {
uint8_t c = str[index];
uint8_t k = ((const uint8_t *)other)[index];
if (c < k) return -1;
if (c > k) return 1;
if (k == '\0') break;
}
return (other[index] == '\0') ? 0 : -1;
}
/* Find an instruction definition given its name */
static const DstInstructionDef *dst_findi(const uint8_t *key) {
const DstInstructionDef *low = dst_ops;
const DstInstructionDef *hi = dst_ops + (sizeof(dst_ops) / sizeof(DstInstructionDef));
while (low < hi) {
const DstInstructionDef *mid = low + ((hi - low) / 2);
int comp = dst_strcompare(key, mid->name);
if (comp < 0) {
hi = mid;
} else if (comp > 0) {
low = mid + 1;
} else {
return mid;
}
}
return NULL;
}
/* Check a dst string against a bunch of test_strings. Return the
* index of the matching test_string, or -1 if not found. */
static int strsearch(const uint8_t *str, const char **test_strings) {
uint32_t len = dst_string_length(str);
int index;
for (index = 0; ; index++) {
uint32_t i;
const char *testword = test_strings[index];
if (NULL == testword)
break;
for (i = 0; i < len; i++) {
if (testword[i] != str[i])
goto nextword;
}
return index;
nextword:
continue;
}
return -1;
}
/* Deinitialize an Assembler. Does not deinitialize the parents. */
static void dst_asm_deinit(DstAssembler *a) {
dst_table_deinit(&a->slots);
dst_table_deinit(&a->labels);
dst_table_deinit(&a->envs);
dst_table_deinit(&a->constants);
}
/* Throw some kind of assembly error */
static void dst_asm_error(DstAssembler *a, const char *message) {
a->errmessage = message;
longjmp(a->on_error, 1);
}
#define dst_asm_assert(a, c, m) do { if (!(c)) dst_asm_error((a), (m)); } while (0)
/* Parse an argument to an assembly instruction, and return the result as an
* integer. This integer will need to be trimmed and bound checked. */
static int64_t doarg_1(DstAssembler *a, DstOpArgType argtype, DstValue x) {
DstTable *c;
switch (argtype) {
case DST_OAT_SLOT:
c = &a->slots;
break;
case DST_OAT_ENVIRONMENT:
c = &a->envs;
break;
case DST_OAT_CONSTANT:
c = &a->constants;
break;
case DST_OAT_INTEGER:
c = NULL;
break;
case DST_OAT_TYPE:
case DST_OAT_SIMPLETYPE:
c = NULL;
break;
case DST_OAT_LABEL:
c = &a->labels;
break;
}
switch (x.type) {
default:
break;
case DST_INTEGER:
return x.as.integer;
case DST_TUPLE:
{
if (argtype == DST_OAT_TYPE) {
int64_t result = 0;
uint32_t i = 0;
for (i = 0; i < dst_tuple_length(x.as.tuple); i++) {
result |= doarg_1(a, DST_OAT_SIMPLETYPE, x.as.tuple[i]);
}
return result;
}
break;
}
case DST_SYMBOL:
{
if (NULL != c) {
DstValue result = dst_table_get(c, x);
if (result.type == DST_INTEGER) {
if (argtype == DST_OAT_LABEL)
return result.as.integer - a->bytecode_count;
return result.as.integer;
} else {
dst_asm_error(a, "unknown name");
}
} else if (argtype == DST_OAT_TYPE || argtype == DST_OAT_SIMPLETYPE) {
int index = strsearch(x.as.string, dst_type_names);
if (index != -1) {
return (int64_t) index;
} else {
dst_asm_error(a, "unknown type");
}
}
break;
}
}
dst_asm_error(a, "unexpected type parsing instruction argument");
return 0;
}
/* Trim a bytecode operand to 1, 2, or 3 bytes. Error out if
* the given argument doesn't fit in the required number of bytes. */
static uint32_t doarg_2(DstAssembler *a, int nbytes, int hassign, int64_t arg) {
/* Calculate the min and max values that can be stored given
* nbytes, and whether or not the storage is signed */
int64_t min = (-hassign) << ((nbytes << 3) - 1);
int64_t max = ~((-1) << ((nbytes << 3) - hassign));
if (arg < min)
dst_asm_error(a, "instruction argument is too small");
if (arg > max)
dst_asm_error(a, "instruction argument is too large");
return (uint32_t) (arg & 0xFFFFFFFF);
}
/* Parse a single argument to an instruction. Trims it as well as
* try to convert arguments to bit patterns */
static uint32_t doarg(DstAssembler *a, DstOpArgType argtype, int nth, int nbytes, int hassign, DstValue x) {
int64_t arg1 = doarg_1(a, argtype, x);
return doarg_2(a, nbytes, hassign, arg1) << (nth << 3);
}
/* Provide parsing methods for the different kinds of arguments */
static uint32_t read_instruction(DstAssembler *a, const DstInstructionDef *idef, const DstValue *argt) {
uint32_t instr = idef->opcode;
switch (idef->type) {
case DIT_0:
{
if (dst_tuple_length(argt) != 1)
dst_asm_error(a, "expected 0 arguments: (op)");
break;
}
case DIT_S:
{
if (dst_tuple_length(argt) != 2)
dst_asm_error(a, "expected 1 argument: (op, slot)");
instr |= doarg(a, DST_OAT_SLOT, 3, 3, 0, argt[1]);
break;
}
case DIT_L:
{
if (dst_tuple_length(argt) != 2)
dst_asm_error(a, "expected 1 argument: (op, label)");
instr |= doarg(a, DST_OAT_LABEL, 3, 3, 1, argt[1]);
break;
}
case DIT_SS:
{
if (dst_tuple_length(argt) != 3)
dst_asm_error(a, "expected 2 arguments: (op, slot, slot)");
instr |= doarg(a, DST_OAT_SLOT, 1, 1, 0, argt[1]);
instr |= doarg(a, DST_OAT_SLOT, 3, 2, 0, argt[2]);
break;
}
case DIT_SL:
{
if (dst_tuple_length(argt) != 3)
dst_asm_error(a, "expected 2 arguments: (op, slot, label)");
instr |= doarg(a, DST_OAT_SLOT, 1, 1, 0, argt[1]);
instr |= doarg(a, DST_OAT_LABEL, 3, 2, 1, argt[2]);
break;
}
case DIT_ST:
{
if (dst_tuple_length(argt) != 3)
dst_asm_error(a, "expected 2 arguments: (op, slot, type)");
instr |= doarg(a, DST_OAT_SLOT, 1, 1, 0, argt[1]);
instr |= doarg(a, DST_OAT_TYPE, 3, 2, 0, argt[2]);
break;
}
case DIT_SI:
case DIT_SU:
{
if (dst_tuple_length(argt) != 3)
dst_asm_error(a, "expected 2 arguments: (op, slot, integer)");
instr |= doarg(a, DST_OAT_SLOT, 1, 1, 0, argt[1]);
instr |= doarg(a, DST_OAT_INTEGER, 3, 2, idef->type == DIT_SI, argt[2]);
break;
}
case DIT_SSS:
{
if (dst_tuple_length(argt) != 4)
dst_asm_error(a, "expected 3 arguments: (op, slot, slot, slot)");
instr |= doarg(a, DST_OAT_SLOT, 1, 1, 0, argt[1]);
instr |= doarg(a, DST_OAT_SLOT, 2, 1, 0, argt[2]);
instr |= doarg(a, DST_OAT_SLOT, 3, 1, 0, argt[3]);
break;
}
case DIT_SES:
{
DstAssembler *b = a;
uint32_t env;
if (dst_tuple_length(argt) != 4)
dst_asm_error(a, "expected 3 arguments: (op, slot, environment, envslot)");
instr |= doarg(a, DST_OAT_SLOT, 1, 1, 0, argt[1]);
env = doarg(a, DST_OAT_ENVIRONMENT, 0, 1, 0, argt[2]);
instr |= env << 16;
for (env += 1; env > 0; env--) {
b = b->parent;
if (NULL == b)
dst_asm_error(a, "invalid environment index");
}
instr |= doarg(b, DST_OAT_SLOT, 3, 1, 0, argt[3]);
break;
}
case DIT_SC:
{
if (dst_tuple_length(argt) != 3)
dst_asm_error(a, "expected 2 arguments: (op, slot, constant)");
instr |= doarg(a, DST_OAT_SLOT, 1, 1, 0, argt[1]);
instr |= doarg(a, DST_OAT_CONSTANT, 3, 2, 0, argt[2]);
break;
}
}
return instr;
}
/* Add a closure environment to the assembler. Sub funcdefs may need
* to reference outer function environments, and may change the outer environment.
* Returns the index of the environment in the assembler's environments, or -1
* if not found. */
static int64_t dst_asm_addenv(DstAssembler *a, DstValue envname) {
DstValue check;
DstFuncDef *def = a->def;
uint32_t oldlen;
int64_t res;
/* Check for memoized value */
check = dst_table_get(&a->envs, envname);
if (check.type != DST_NIL) {
return check.as.integer;
}
if (NULL == a->parent) {
return -1;
}
res = dst_asm_addenv(a->parent, envname);
if (res < 0)
return res;
oldlen = def->environments_length;
dst_table_put(&a->envs, envname, dst_wrap_integer(def->environments_length));
if (oldlen >= a->environments_capacity) {
uint32_t newcap = 2 + 2 * oldlen;
def->environments = realloc(def->environments, newcap * sizeof(uint32_t));
if (NULL == def->environments) {
DST_OUT_OF_MEMORY;
}
a->environments_capacity = newcap;
}
def->environments[def->environments_length++] = (uint32_t) res;
return (int64_t) oldlen;
}
/* Helper to assembly. Return the assembled funcdef */
static DstFuncDef *dst_asm1(DstAssembler *parent, DstValue src, const char **errout) {
DstAssembler a;
DstTable *t = src.as.table;
DstFuncDef *def;
uint32_t count, i;
const DstValue *arr;
DstValue x;
/* Initialize funcdef */
def = dst_alloc(DST_MEMORY_FUNCDEF, sizeof(DstFuncDef));
if (NULL == def) {
DST_OUT_OF_MEMORY;
}
def->environments = NULL;
def->constants = NULL;
def->bytecode = NULL;
def->flags = 0;
def->slotcount = 0;
def->arity = 0;
def->constants_length = 0;
def->bytecode_length = 0;
def->environments_length = 0;
/* Initialize Assembler */
a.def = def;
a.parent = parent;
a.errmessage = NULL;
a.environments_capacity = 0;
a.bytecode_count = 0;
dst_table_init(&a.labels, 10);
dst_table_init(&a.constants, 10);
dst_table_init(&a.slots, 10);
dst_table_init(&a.envs, 10);
/* Set error jump */
if (setjmp(a.on_error)) {
dst_asm_deinit(&a);
if (NULL != a.parent) {
longjmp(a.parent->on_error, 1);
}
*errout = a.errmessage;
return NULL;
}
dst_asm_assert(&a, src.type == DST_TABLE, "expected table for assembly");
/* Set function arity */
x = dst_table_get(t, dst_wrap_symbol(dst_cstring("arity")));
def->arity = x.type == DST_INTEGER ? x.as.integer : 0;
/* Create slot aliases */
x = dst_table_get(t, dst_wrap_symbol(dst_cstring("slots")));
if (dst_seq_view(x, &arr, &count)) {
def->slotcount = count;
for (i = 0; i < count; i++) {
DstValue v = arr[i];
if (v.type == DST_TUPLE) {
uint32_t j;
for (j = 0; j < dst_tuple_length(v.as.tuple); j++) {
if (v.as.tuple[j].type != DST_SYMBOL)
dst_asm_error(&a, "slot names must be symbols");
dst_table_put(&a.slots, v.as.tuple[j], dst_wrap_integer(i));
}
} else if (v.type == DST_SYMBOL) {
dst_table_put(&a.slots, v, dst_wrap_integer(i));
} else {
dst_asm_error(&a, "slot names must be symbols or tuple of symbols");
}
}
} else if (x.type == DST_INTEGER) {
def->slotcount = (uint32_t) x.as.integer;
} else {
dst_asm_error(&a, "slots must be specified");
}
/* Create environment aliases */
x = dst_table_get(t, dst_wrap_symbol(dst_cstring("environments")));
if (dst_seq_view(x, &arr, &count)) {
for (i = 0; i < count; i++) {
dst_asm_assert(&a, arr[i].type == DST_SYMBOL, "environment must be a symbol");
if (dst_asm_addenv(&a, arr[i]) < 0) {
dst_asm_error(&a, "environment not found");
}
}
}
/* Parse constants */
x = dst_table_get(t, dst_wrap_symbol(dst_cstring("constants")));
if (dst_seq_view(x, &arr, &count)) {
def->constants_length = count;
def->constants = malloc(sizeof(DstValue) * count);
if (NULL == def->constants) {
DST_OUT_OF_MEMORY;
}
for (i = 0; i < count; i++) {
DstValue ct = arr[i];
if (ct.type == DST_TUPLE &&
dst_tuple_length(ct.as.tuple) > 1 &&
ct.as.tuple[0].type == DST_SYMBOL) {
uint32_t tcount = dst_tuple_length(ct.as.tuple);
const uint8_t *macro = ct.as.tuple[0].as.string;
if (0 == dst_strcompare(macro, "quote")) {
def->constants[i] = ct.as.tuple[1];
} else if (tcount == 3 &&
ct.as.tuple[1].type == DST_SYMBOL &&
0 == dst_strcompare(macro, "def")) {
def->constants[i] = ct.as.tuple[2];
dst_table_put(&a.constants, ct.as.tuple[1], dst_wrap_integer(i));
} else {
dst_asm_error(&a, "could not parse constant");
}
/* Todo - parse nested funcdefs */
} else {
def->constants[i] = ct;
}
}
} else {
def->constants = NULL;
def->constants_length = 0;
}
/* Parse bytecode and labels */
x = dst_table_get(t, dst_wrap_symbol(dst_cstring("bytecode")));
if (dst_seq_view(x, &arr, &count)) {
/* Do labels and find length */
uint32_t blength = 0;
for (i = 0; i < count; ++i) {
DstValue instr = arr[i];
if (instr.type == DST_STRING) {
dst_table_put(&a.labels, instr, dst_wrap_integer(blength));
} else if (instr.type == DST_TUPLE) {
blength++;
} else {
dst_asm_error(&a, "expected assembly instruction");
}
}
/* Allocate bytecode array */
def->bytecode_length = blength;
def->bytecode = malloc(sizeof(uint32_t) * blength);
if (NULL == def->bytecode) {
DST_OUT_OF_MEMORY;
}
/* Do bytecode */
for (i = 0; i < count; ++i) {
DstValue instr = arr[i];
if (instr.type == DST_STRING) {
continue;
} else {
uint32_t op;
const DstInstructionDef *idef;
dst_asm_assert(&a, instr.type == DST_TUPLE, "expected tuple");
if (dst_tuple_length(instr.as.tuple) == 0) {
op = 0;
} else {
dst_asm_assert(&a, instr.as.tuple[0].type == DST_SYMBOL,
"expected symbol in assembly instruction");
idef = dst_findi(instr.as.tuple[0].as.string);
dst_asm_assert(&a, NULL != idef, "unknown instruction");
op = read_instruction(&a, idef, instr.as.tuple);
}
def->bytecode[a.bytecode_count++] = op;
}
}
} else {
dst_asm_error(&a, "bytecode expected");
}
/* Finish everything and return funcdef */
dst_asm_deinit(&a);
def->environments =
realloc(def->environments, def->environments_length * sizeof(uint32_t));
return def;
}
/* Assembled a function definition. */
int dst_asm(DstFuncDef **out, DstValue source) {
const char *err;
DstFuncDef *ret = dst_asm1(NULL, source, &err);
if (NULL == ret) {
return 1;
}
*out = ret;
return 0;
}
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