ref: 131ad9b315960d46cc5b0cb9d1c6f052de11f26a
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 <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "asm/asm.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 {
char tzFilename[_MAX_PATH + 1];
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;
/*
* Count the number of sections used in this object
*/
static uint32_t countsections(void)
{
struct Section *sect;
uint32_t count = 0;
sect = pSectionList;
while (sect) {
count++;
sect = sect->next;
}
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 fputlong(uint32_t i, FILE *f)
{
fputc(i, f);
fputc(i >> 8, f);
fputc(i >> 16, f);
fputc(i >> 24, f);
}
/*
* Write a NULL-terminated string to a file
*/
static void fputstring(char const *s, FILE *f)
{
while (*s)
fputc(*s++, f);
fputc(0, f);
}
/*
* Return a section's ID
*/
static uint32_t getsectid(struct Section const *sect)
{
struct Section const *sec;
uint32_t ID = 0;
sec = pSectionList;
while (sec) {
if (sec == sect)
return ID;
ID++;
sec = sec->next;
}
fatalerror("Unknown section '%s'", 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)
{
fputstring(patch->tzFilename, f);
fputlong(patch->nOffset, f);
fputlong(getSectIDIfAny(patch->pcSection), f);
fputlong(patch->pcOffset, f);
fputc(patch->type, f);
fputlong(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)
{
fputstring(sect->name, f);
fputlong(sect->size, f);
bool isUnion = sect->modifier == SECTION_UNION;
bool isFragment = sect->modifier == SECTION_FRAGMENT;
fputc(sect->type | isUnion << 7 | isFragment << 6, f);
fputlong(sect->org, f);
fputlong(sect->bank, f);
fputc(sect->align, f);
fputlong(sect->alignOfs, f);
if (sect_HasData(sect->type)) {
fwrite(sect->data, 1, sect->size, f);
fputlong(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)
{
fputstring(sym->name, f);
if (!sym_IsDefined(sym)) {
fputc(SYMTYPE_IMPORT, f);
} else {
fputc(sym->isExported ? SYMTYPE_EXPORT : SYMTYPE_LOCAL, f);
fputstring(sym->fileName, f);
fputlong(sym->fileLine, f);
fputlong(getSectIDIfAny(sym_GetSection(sym)), f);
fputlong(sym->value, f);
}
}
/*
* 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 == -1) {
sym->ID = nbSymbols++;
*objectSymbolsTail = sym;
objectSymbolsTail = &sym->next;
}
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) {
case RPN_CONST:
writebyte(RPN_CONST);
writebyte(popbyte());
writebyte(popbyte());
writebyte(popbyte());
writebyte(popbyte());
break;
case RPN_SYM:
{
for (unsigned int i = -1; (tzSym[++i] = popbyte()); )
;
struct Symbol *sym = sym_FindSymbol(tzSym);
uint32_t value;
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:
{
for (unsigned int i = -1; (tzSym[++i] = popbyte()); )
;
struct Symbol *sym = sym_FindSymbol(tzSym);
uint32_t value = getSymbolID(sym);
writebyte(RPN_BANK_SYM);
writebyte(value & 0xFF);
writebyte(value >> 8);
writebyte(value >> 16);
writebyte(value >> 24);
break;
}
case RPN_BANK_SECT:
{
uint8_t b;
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
*/
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;
if (!patch)
fatalerror("No memory for patch: %s", strerror(errno));
patch->pRPN = malloc(sizeof(*patch->pRPN) * rpnSize);
if (!patch->pRPN)
fatalerror("No memory for patch's RPN expression: %s",
strerror(errno));
patch->type = type;
fstk_DumpToStr(patch->tzFilename, sizeof(patch->tzFilename));
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)
{
struct Patch *patch = allocpatch(type, expr, ofs);
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);
fputstring(assert->message, f);
}
static void registerExportedSymbol(struct Symbol *symbol, void *arg)
{
(void)arg;
if (sym_IsExported(symbol) && symbol->ID == -1) {
*objectSymbolsTail = symbol;
objectSymbolsTail = &symbol->next;
nbSymbols++;
}
}
/*
* Write an objectfile
*/
void out_WriteObject(void)
{
FILE *f = fopen(tzObjectname, "wb");
if (!f)
err(1, "Couldn't write file '%s'", tzObjectname);
/* Also write exported symbols that weren't written above */
sym_ForEach(registerExportedSymbol, NULL);
fprintf(f, RGBDS_OBJECT_VERSION_STRING, RGBDS_OBJECT_VERSION_NUMBER);
fputlong(RGBDS_OBJECT_REV, f);
fputlong(nbSymbols, f);
fputlong(countsections(), f);
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);
fputlong(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);
}