ref: c7ed9a275e793e9f6509cc6e900cb5d1c659c6b1
dir: /src/asm/output.c/
/*
* This file is part of RGBDS.
*
* Copyright (c) 1997-2019, Carsten Sorensen and RGBDS contributors.
*
* SPDX-License-Identifier: MIT
*/
/*
* Outputs an objectfile
*/
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "asm/charmap.h"
#include "asm/fstack.h"
#include "asm/main.h"
#include "asm/output.h"
#include "asm/rpn.h"
#include "asm/section.h"
#include "asm/symbol.h"
#include "asm/warning.h"
#include "extern/err.h"
#include "linkdefs.h"
#include "platform.h" // strdup
struct Patch {
struct FileStackNode const *src;
uint32_t lineNo;
uint32_t nOffset;
struct Section *pcSection;
uint32_t pcOffset;
uint8_t type;
uint32_t nRPNSize;
uint8_t *pRPN;
struct Patch *next;
};
struct Assertion {
struct Patch *patch;
struct Section *section;
char *message;
struct Assertion *next;
};
char *tzObjectname;
/* TODO: shouldn't `pCurrentSection` be somewhere else? */
struct Section *pSectionList, *pCurrentSection;
/* Linked list of symbols to put in the object file */
static struct Symbol *objectSymbols = NULL;
static struct Symbol **objectSymbolsTail = &objectSymbols;
static uint32_t nbSymbols = 0; /* Length of the above list */
static struct Assertion *assertions = NULL;
static struct FileStackNode *fileStackNodes = NULL;
/*
* Count the number of sections used in this object
*/
static uint32_t countSections(void)
{
uint32_t count = 0;
for (struct Section const *sect = pSectionList; sect; sect = sect->next)
count++;
return count;
}
/*
* Count the number of patches used in this object
*/
static uint32_t countPatches(struct Section const *sect)
{
uint32_t r = 0;
for (struct Patch const *patch = sect->patches; patch != NULL;
patch = patch->next)
r++;
return r;
}
/**
* Count the number of assertions used in this object
*/
static uint32_t countAsserts(void)
{
struct Assertion *assert = assertions;
uint32_t count = 0;
while (assert) {
count++;
assert = assert->next;
}
return count;
}
/*
* Write a long to a file (little-endian)
*/
static void putlong(uint32_t i, FILE *f)
{
putc(i, f);
putc(i >> 8, f);
putc(i >> 16, f);
putc(i >> 24, f);
}
/*
* Write a NULL-terminated string to a file
*/
static void putstring(char const *s, FILE *f)
{
while (*s)
putc(*s++, f);
putc(0, f);
}
static uint32_t getNbFileStackNodes(void)
{
return fileStackNodes ? fileStackNodes->ID + 1 : 0;
}
void out_RegisterNode(struct FileStackNode *node)
{
/* If node is not already registered, register it (and parents), and give it a unique ID */
while (node->ID == (uint32_t)-1) {
node->ID = getNbFileStackNodes();
if (node->ID == (uint32_t)-1)
fatalerror("Reached too many file stack nodes; try splitting the file up\n");
node->next = fileStackNodes;
fileStackNodes = node;
/* Also register the node's parents */
node = node->parent;
if (!node)
break;
}
}
void out_ReplaceNode(struct FileStackNode *node)
{
(void)node;
#if 0
This is code intended to replace a node, which is pretty useless until ref counting is added...
struct FileStackNode **ptr = &fileStackNodes;
/*
* The linked list is supposed to have decrementing IDs, so iterate with less memory reads,
* to hopefully hit the cache less. A debug check is added after, in case a change is made
* that breaks this assumption.
*/
for (uint32_t i = fileStackNodes->ID; i != node->ID; i--)
ptr = &(*ptr)->next;
assert((*ptr)->ID == node->ID);
node->next = (*ptr)->next;
assert(!node->next || node->next->ID == node->ID - 1); /* Catch inconsistencies early */
/* TODO: unreference the node */
*ptr = node;
#endif
}
/*
* Return a section's ID
*/
static uint32_t getsectid(struct Section const *sect)
{
struct Section const *sec = pSectionList;
uint32_t ID = 0;
while (sec) {
if (sec == sect)
return ID;
ID++;
sec = sec->next;
}
fatalerror("Unknown section '%s'\n", sect->name);
}
static uint32_t getSectIDIfAny(struct Section const *sect)
{
return sect ? getsectid(sect) : -1;
}
/*
* Write a patch to a file
*/
static void writepatch(struct Patch const *patch, FILE *f)
{
assert(patch->src->ID != -1);
putlong(patch->src->ID, f);
putlong(patch->lineNo, f);
putlong(patch->nOffset, f);
putlong(getSectIDIfAny(patch->pcSection), f);
putlong(patch->pcOffset, f);
putc(patch->type, f);
putlong(patch->nRPNSize, f);
fwrite(patch->pRPN, 1, patch->nRPNSize, f);
}
/*
* Write a section to a file
*/
static void writesection(struct Section const *sect, FILE *f)
{
putstring(sect->name, f);
putlong(sect->size, f);
bool isUnion = sect->modifier == SECTION_UNION;
bool isFragment = sect->modifier == SECTION_FRAGMENT;
putc(sect->type | isUnion << 7 | isFragment << 6, f);
putlong(sect->org, f);
putlong(sect->bank, f);
putc(sect->align, f);
putlong(sect->alignOfs, f);
if (sect_HasData(sect->type)) {
fwrite(sect->data, 1, sect->size, f);
putlong(countPatches(sect), f);
for (struct Patch const *patch = sect->patches; patch != NULL;
patch = patch->next)
writepatch(patch, f);
}
}
/*
* Write a symbol to a file
*/
static void writesymbol(struct Symbol const *sym, FILE *f)
{
putstring(sym->name, f);
if (!sym_IsDefined(sym)) {
putc(SYMTYPE_IMPORT, f);
} else {
assert(sym->src->ID != -1);
putc(sym->isExported ? SYMTYPE_EXPORT : SYMTYPE_LOCAL, f);
putlong(sym->src->ID, f);
putlong(sym->fileLine, f);
putlong(getSectIDIfAny(sym_GetSection(sym)), f);
putlong(sym->value, f);
}
}
static void registerSymbol(struct Symbol *sym)
{
*objectSymbolsTail = sym;
objectSymbolsTail = &sym->next;
out_RegisterNode(sym->src);
if (nbSymbols == (uint32_t)-1)
fatalerror("Registered too many symbols (%" PRIu32
"); try splitting up your files\n", (uint32_t)-1);
sym->ID = nbSymbols++;
}
/*
* Returns a symbol's ID within the object file
* If the symbol does not have one, one is assigned by registering the symbol
*/
static uint32_t getSymbolID(struct Symbol *sym)
{
if (sym->ID == (uint32_t)-1 && !sym_IsPC(sym))
registerSymbol(sym);
return sym->ID;
}
static void writerpn(uint8_t *rpnexpr, uint32_t *rpnptr, uint8_t *rpn,
uint32_t rpnlen)
{
char tzSym[512];
for (size_t offset = 0; offset < rpnlen; ) {
#define popbyte() rpn[offset++]
#define writebyte(byte) rpnexpr[(*rpnptr)++] = byte
uint8_t rpndata = popbyte();
switch (rpndata) {
struct Symbol *sym;
uint32_t value;
uint8_t b;
size_t i;
case RPN_CONST:
writebyte(RPN_CONST);
writebyte(popbyte());
writebyte(popbyte());
writebyte(popbyte());
writebyte(popbyte());
break;
case RPN_SYM:
i = 0;
do {
tzSym[i] = popbyte();
} while (tzSym[i++]);
// The symbol name is always written expanded
sym = sym_FindExactSymbol(tzSym);
if (sym_IsConstant(sym)) {
writebyte(RPN_CONST);
value = sym_GetConstantValue(tzSym);
} else {
writebyte(RPN_SYM);
value = getSymbolID(sym);
}
writebyte(value & 0xFF);
writebyte(value >> 8);
writebyte(value >> 16);
writebyte(value >> 24);
break;
case RPN_BANK_SYM:
i = 0;
do {
tzSym[i] = popbyte();
} while (tzSym[i++]);
// The symbol name is always written expanded
sym = sym_FindExactSymbol(tzSym);
value = getSymbolID(sym);
writebyte(RPN_BANK_SYM);
writebyte(value & 0xFF);
writebyte(value >> 8);
writebyte(value >> 16);
writebyte(value >> 24);
break;
case RPN_BANK_SECT:
writebyte(RPN_BANK_SECT);
do {
b = popbyte();
writebyte(b);
} while (b != 0);
break;
default:
writebyte(rpndata);
break;
}
#undef popbyte
#undef writebyte
}
}
/*
* Allocate a new patch structure and link it into the list
* WARNING: all patches are assumed to eventually be written, so the file stack node is registered
*/
static struct Patch *allocpatch(uint32_t type, struct Expression const *expr, uint32_t ofs)
{
struct Patch *patch = malloc(sizeof(struct Patch));
uint32_t rpnSize = expr->isKnown ? 5 : expr->nRPNPatchSize;
struct FileStackNode *node = fstk_GetFileStack();
if (!patch)
fatalerror("No memory for patch: %s\n", strerror(errno));
patch->pRPN = malloc(sizeof(*patch->pRPN) * rpnSize);
if (!patch->pRPN)
fatalerror("No memory for patch's RPN expression: %s\n", strerror(errno));
patch->type = type;
patch->src = node;
out_RegisterNode(node);
patch->lineNo = lexer_GetLineNo();
patch->nOffset = ofs;
patch->pcSection = sect_GetSymbolSection();
patch->pcOffset = sect_GetSymbolOffset();
/* If the expression's value is known, output a constant RPN expression directly */
if (expr->isKnown) {
patch->nRPNSize = rpnSize;
/* Make sure to update `rpnSize` above if modifying this! */
patch->pRPN[0] = RPN_CONST;
patch->pRPN[1] = (uint32_t)(expr->nVal) & 0xFF;
patch->pRPN[2] = (uint32_t)(expr->nVal) >> 8;
patch->pRPN[3] = (uint32_t)(expr->nVal) >> 16;
patch->pRPN[4] = (uint32_t)(expr->nVal) >> 24;
} else {
patch->nRPNSize = 0;
writerpn(patch->pRPN, &patch->nRPNSize, expr->tRPN, expr->nRPNLength);
}
assert(patch->nRPNSize == rpnSize);
return patch;
}
/*
* Create a new patch (includes the rpn expr)
*/
void out_CreatePatch(uint32_t type, struct Expression const *expr, uint32_t ofs, uint32_t pcShift)
{
struct Patch *patch = allocpatch(type, expr, ofs);
// If the patch had a quantity of bytes output before it,
// PC is not at the patch's location, but at the location
// before those bytes.
patch->pcOffset -= pcShift;
patch->next = pCurrentSection->patches;
pCurrentSection->patches = patch;
}
/**
* Creates an assert that will be written to the object file
*/
bool out_CreateAssert(enum AssertionType type, struct Expression const *expr,
char const *message, uint32_t ofs)
{
struct Assertion *assertion = malloc(sizeof(*assertion));
if (!assertion)
return false;
assertion->patch = allocpatch(type, expr, ofs);
assertion->message = strdup(message);
if (!assertion->message) {
free(assertion);
return false;
}
assertion->next = assertions;
assertions = assertion;
return true;
}
static void writeassert(struct Assertion *assert, FILE *f)
{
writepatch(assert->patch, f);
putstring(assert->message, f);
}
static void writeFileStackNode(struct FileStackNode const *node, FILE *f)
{
putlong(node->parent ? node->parent->ID : -1, f);
putlong(node->lineNo, f);
putc(node->type, f);
if (node->type != NODE_REPT) {
putstring(((struct FileStackNamedNode const *)node)->name, f);
} else {
struct FileStackReptNode const *reptNode = (struct FileStackReptNode const *)node;
putlong(reptNode->reptDepth, f);
/* Iters are stored by decreasing depth, so reverse the order for output */
for (uint32_t i = reptNode->reptDepth; i--; )
putlong(reptNode->iters[i], f);
}
}
static void registerUnregisteredSymbol(struct Symbol *symbol, void *arg)
{
(void)arg; // sym_ForEach requires a void* parameter, but we are not using it.
// Check for symbol->src, to skip any built-in symbol from rgbasm
if (symbol->src && symbol->ID == (uint32_t)-1) {
registerSymbol(symbol);
}
}
/*
* Write an objectfile
*/
void out_WriteObject(void)
{
FILE *f;
if (strcmp(tzObjectname, "-") != 0)
f = fopen(tzObjectname, "wb");
else
f = fdopen(1, "wb");
if (!f)
err(1, "Couldn't write file '%s'", tzObjectname);
/* Also write symbols that weren't written above */
sym_ForEach(registerUnregisteredSymbol, NULL);
fprintf(f, RGBDS_OBJECT_VERSION_STRING, RGBDS_OBJECT_VERSION_NUMBER);
putlong(RGBDS_OBJECT_REV, f);
putlong(nbSymbols, f);
putlong(countSections(), f);
putlong(getNbFileStackNodes(), f);
for (struct FileStackNode const *node = fileStackNodes; node; node = node->next) {
writeFileStackNode(node, f);
if (node->next && node->next->ID != node->ID - 1)
fatalerror("Internal error: fstack node #%" PRIu32 " follows #%" PRIu32
". Please report this to the developers!\n",
node->next->ID, node->ID);
}
for (struct Symbol const *sym = objectSymbols; sym; sym = sym->next)
writesymbol(sym, f);
for (struct Section *sect = pSectionList; sect; sect = sect->next)
writesection(sect, f);
putlong(countAsserts(), f);
for (struct Assertion *assert = assertions; assert;
assert = assert->next)
writeassert(assert, f);
fclose(f);
}
/*
* Set the objectfilename
*/
void out_SetFileName(char *s)
{
tzObjectname = s;
if (verbose)
printf("Output filename %s\n", s);
}