ref: 4b33b4b3875635f1c1a1aba1a2beb0e946d175c5
dir: /src/link/object.c/
/*
* This file is part of RGBDS.
*
* Copyright (c) 2019, Eldred Habert and RGBDS contributors.
*
* SPDX-License-Identifier: MIT
*/
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <limits.h>
#include "link/object.h"
#include "link/main.h"
#include "link/symbol.h"
#include "link/section.h"
#include "link/assign.h"
#include "extern/err.h"
#include "linkdefs.h"
static struct SymbolList {
size_t nbSymbols;
struct Symbol **symbolList;
struct SymbolList *next;
} *symbolLists;
/***** Helper functions for reading object files *****/
/*
* Internal, DO NOT USE.
* For helper wrapper macros defined below, such as `tryReadlong`
*/
#define tryRead(func, type, errval, var, file, ...) \
do { \
FILE *tmpFile = file; \
type tmpVal = func(tmpFile); \
if (tmpVal == (errval)) { \
errx(1, __VA_ARGS__, feof(tmpFile) \
? "Unexpected end of file" \
: strerror(errno)); \
} \
var = tmpVal; \
} while (0)
/**
* Reads an unsigned long (32-bit) value from a file.
* @param file The file to read from. This will read 4 bytes from the file.
* @return The value read, cast to a int64_t, or -1 on failure.
*/
static int64_t readlong(FILE *file)
{
uint32_t value = 0;
/* Read the little-endian value byte by byte */
for (uint8_t shift = 0; shift < sizeof(value) * CHAR_BIT; shift += 8) {
int byte = getc(file);
if (byte == EOF)
return INT64_MAX;
/* This must be casted to `unsigned`, not `uint8_t`. Rationale:
* the type of the shift is the type of `byte` after undergoing
* integer promotion, which would be `int` if this was casted to
* `uint8_t`, because int is large enough to hold a byte. This
* however causes values larger than 127 to be too large when
* shifted, potentially triggering undefined behavior.
*/
value |= (unsigned int)byte << shift;
}
return value;
}
/**
* Helper macro for reading longs from a file, and errors out if it fails to.
* Not as a function to avoid overhead in the general case.
* TODO: maybe mark the condition as `unlikely`; how to do that portably?
* @param var The variable to stash the number into
* @param file The file to read from. Its position will be advanced
* @param ... A format string and related arguments; note that an extra string
* argument is provided, the reason for failure
*/
#define tryReadlong(var, file, ...) \
tryRead(readlong, int64_t, INT64_MAX, var, file, __VA_ARGS__)
/* There is no `readbyte`, just use `fgetc` or `getc`. */
/**
* Helper macro for reading bytes from a file, and errors out if it fails to.
* Differs from `tryGetc` in that the backing function is fgetc(1).
* Not as a function to avoid overhead in the general case.
* TODO: maybe mark the condition as `unlikely`; how to do that portably?
* @param var The variable to stash the number into
* @param file The file to read from. Its position will be advanced
* @param ... A format string and related arguments; note that an extra string
* argument is provided, the reason for failure
*/
#define tryFgetc(var, file, ...) \
tryRead(fgetc, int, EOF, var, file, __VA_ARGS__)
/**
* Helper macro for reading bytes from a file, and errors out if it fails to.
* Differs from `tryGetc` in that the backing function is fgetc(1).
* Not as a function to avoid overhead in the general case.
* TODO: maybe mark the condition as `unlikely`; how to do that portably?
* @param var The variable to stash the number into
* @param file The file to read from. Its position will be advanced
* @param ... A format string and related arguments; note that an extra string
* argument is provided, the reason for failure
*/
#define tryGetc(var, file, ...) \
tryRead(getc, int, EOF, var, file, __VA_ARGS__)
/**
* Reads a '\0'-terminated string from a file.
* @param file The file to read from. The file position will be advanced.
* @return The string read, or NULL on failure.
* If a non-NULL pointer is returned, make sure to `free` it when done!
*/
static char *readstr(FILE *file)
{
/* Default buffer size, have it close to the average string length */
size_t capacity = 32 / 2;
size_t index = -1;
/* Force the first iteration to allocate */
char *str = NULL;
do {
/* Prepare going to next char */
index++;
/* If the buffer isn't suitable to write the next char... */
if (index >= capacity || !str) {
capacity *= 2;
str = realloc(str, capacity);
/* End now in case of error */
if (!str)
return NULL;
}
/* Read char */
int byte = getc(file);
if (byte == EOF)
return NULL;
str[index] = byte;
} while (str[index]);
return str;
}
/**
* Helper macro for reading bytes from a file, and errors out if it fails to.
* Not as a function to avoid overhead in the general case.
* TODO: maybe mark the condition as `unlikely`; how to do that portably?
* @param var The variable to stash the string into
* @param file The file to read from. Its position will be advanced
* @param ... A format string and related arguments; note that an extra string
* argument is provided, the reason for failure
*/
#define tryReadstr(var, file, ...) \
tryRead(readstr, char*, NULL, var, file, __VA_ARGS__)
/***** Functions to parse object files *****/
/**
* Reads a RGB6 symbol from a file.
* @param file The file to read from
* @param symbol The struct to fill
* @param fileName The filename to report in errors
*/
static void readSymbol(FILE *file, struct Symbol *symbol, char const *fileName)
{
tryReadstr(symbol->name, file, "%s: Cannot read symbol name: %s",
fileName);
tryGetc(symbol->type, file, "%s: Cannot read \"%s\"'s type: %s",
fileName, symbol->name);
/* If the symbol is defined in this file, read its definition */
if (symbol->type != SYMTYPE_IMPORT) {
symbol->objFileName = fileName;
tryReadstr(symbol->fileName, file,
"%s: Cannot read \"%s\"'s file name: %s",
fileName, symbol->name);
tryReadlong(symbol->lineNo, file,
"%s: Cannot read \"%s\"'s line number: %s",
fileName, symbol->name);
tryReadlong(symbol->sectionID, file,
"%s: Cannot read \"%s\"'s section ID: %s",
fileName, symbol->name);
tryReadlong(symbol->offset, file,
"%s: Cannot read \"%s\"'s value: %s",
fileName, symbol->name);
} else {
symbol->sectionID = -1;
}
}
/**
* Reads a RGB6 patch from a file.
* @param file The file to read from
* @param patch The struct to fill
* @param fileName The filename to report in errors
* @param i The number of the patch to report in errors
*/
static void readPatch(FILE *file, struct Patch *patch,
char const *fileName, char const *sectName, uint32_t i)
{
tryReadstr(patch->fileName, file,
"%s: Unable to read \"%s\"'s patch #%u's name: %s",
fileName, sectName, i);
tryReadlong(patch->offset, file,
"%s: Unable to read \"%s\"'s patch #%u's offset: %s",
fileName, sectName, i);
tryGetc(patch->type, file,
"%s: Unable to read \"%s\"'s patch #%u's type: %s",
fileName, sectName, i);
tryReadlong(patch->rpnSize, file,
"%s: Unable to read \"%s\"'s patch #%u's RPN size: %s",
fileName, sectName, i);
uint8_t *rpnExpression =
malloc(sizeof(*rpnExpression) * patch->rpnSize);
size_t nbElementsRead = fread(rpnExpression, sizeof(*rpnExpression),
patch->rpnSize, file);
if (nbElementsRead != patch->rpnSize)
errx(1, "%s: Cannot read \"%s\"'s patch #%u's RPN expression: %s",
fileName, sectName, i,
feof(file) ? "Unexpected end of file" : strerror(errno));
patch->rpnExpression = rpnExpression;
}
/**
* Reads a RGB6 section from a file.
* @param file The file to read from
* @param section The struct to fill
* @param fileName The filename to report in errors
*/
static void readSection(FILE *file, struct Section *section,
char const *fileName)
{
int32_t tmp;
tryReadstr(section->name, file, "%s: Cannot read section name: %s",
fileName);
tryReadlong(tmp, file, "%s: Cannot read \"%s\"'s' size: %s",
fileName, section->name);
if (tmp < 0 || tmp > UINT16_MAX)
errx(1, "\"%s\"'s section size (%d) is invalid", section->name,
tmp);
section->size = tmp;
tryGetc(section->type, file, "%s: Cannot read \"%s\"'s type: %s",
fileName, section->name);
tryReadlong(tmp, file, "%s: Cannot read \"%s\"'s org: %s",
fileName, section->name);
section->isAddressFixed = tmp >= 0;
if (tmp > UINT16_MAX)
errx(1, "\"%s\"'s org' is too large (%d)", section->name, tmp);
section->org = tmp;
tryReadlong(tmp, file, "%s: Cannot read \"%s\"'s bank: %s",
fileName, section->name);
section->isBankFixed = tmp >= 0;
section->bank = tmp;
tryReadlong(tmp, file, "%s: Cannot read \"%s\"'s alignment: %s",
fileName, section->name);
section->isAlignFixed = tmp != 1;
section->alignMask = tmp - 1;
if (sect_HasData(section->type)) {
/* Ensure we never allocate 0 bytes */
uint8_t *data = malloc(sizeof(*data) * section->size + 1);
if (!data)
err(1, "%s: Unable to read \"%s\"'s data", fileName,
section->name);
if (section->size) {
size_t nbElementsRead = fread(data, sizeof(*data),
section->size, file);
if (nbElementsRead != section->size)
errx(1, "%s: Cannot read \"%s\"'s data: %s",
fileName, section->name,
feof(file) ? "Unexpected end of file"
: strerror(errno));
}
section->data = data;
tryReadlong(section->nbPatches, file,
"%s: Cannot read \"%s\"'s number of patches: %s",
fileName, section->name);
struct Patch *patches =
malloc(sizeof(*patches) * section->nbPatches + 1);
if (!patches)
err(1, "%s: Unable to read \"%s\"'s patches", fileName,
section->name);
for (uint32_t i = 0; i < section->nbPatches; i++)
readPatch(file, &patches[i], fileName, section->name,
i);
section->patches = patches;
}
}
/**
* Links a symbol to a section, keeping the section's symbol list sorted.
* @param symbol The symbol to link
* @param section The section to link
*/
static void linkSymToSect(struct Symbol const *symbol, struct Section *section)
{
uint32_t a = 0, b = section->nbSymbols;
while (a != b) {
uint32_t c = (a + b) / 2;
if (section->symbols[c]->offset > symbol->offset)
b = c;
else
a = c + 1;
}
struct Symbol const *tmp = symbol;
for (uint32_t i = a; i <= section->nbSymbols; i++) {
symbol = tmp;
tmp = section->symbols[i];
section->symbols[i] = symbol;
}
section->nbSymbols++;
}
/**
* Reads an object file of any supported format
* @param fileName The filename to report for errors
*/
void obj_ReadFile(char const *fileName)
{
FILE *file = strcmp("-", fileName) ? fopen(fileName, "rb") : stdin;
if (!file)
err(1, "Could not open file %s", fileName);
/* Begin by reading the magic bytes and version number */
uint8_t versionNumber;
int matchedElems = fscanf(file, RGBDS_OBJECT_VERSION_STRING,
&versionNumber);
if (matchedElems != 1)
errx(1, "\"%s\" is not a RGBDS object file", fileName);
verbosePrint("Reading object file %s, version %hhu\n",
fileName, versionNumber);
if (versionNumber != RGBDS_OBJECT_VERSION_NUMBER)
errx(1, "\"%s\" is an incompatible version %hhu object file",
fileName, versionNumber);
uint32_t revNum;
tryReadlong(revNum, file, "%s: Cannot read revision number: %s",
fileName);
if (revNum != RGBDS_OBJECT_REV)
errx(1, "%s is a revision 0x%04x object file, only 0x%04x is supported",
fileName, revNum, RGBDS_OBJECT_REV);
uint32_t nbSymbols;
uint32_t nbSections;
tryReadlong(nbSymbols, file, "%s: Cannot read number of symbols: %s",
fileName);
tryReadlong(nbSections, file, "%s: Cannot read number of sections: %s",
fileName);
nbSectionsToAssign += nbSections;
/* This file's symbols, kept to link sections to them */
struct Symbol **fileSymbols =
malloc(sizeof(*fileSymbols) * nbSymbols + 1);
if (!fileSymbols)
err(1, "Failed to get memory for %s's symbols", fileName);
struct SymbolList *symbolList = malloc(sizeof(*symbolList));
if (!symbolList)
err(1, "Failed to register %s's symbol list", fileName);
symbolList->symbolList = fileSymbols;
symbolList->nbSymbols = nbSymbols;
symbolList->next = symbolLists;
symbolLists = symbolList;
uint32_t nbSymPerSect[nbSections ? nbSections : 1];
memset(nbSymPerSect, 0, sizeof(nbSymPerSect));
verbosePrint("Reading %u symbols...\n", nbSymbols);
for (uint32_t i = 0; i < nbSymbols; i++) {
/* Read symbol */
struct Symbol *symbol = malloc(sizeof(*symbol));
if (!symbol)
err(1, "%s: Couldn't create new symbol", fileName);
readSymbol(file, symbol, fileName);
fileSymbols[i] = symbol;
if (symbol->type == SYMTYPE_EXPORT)
sym_AddSymbol(symbol);
if (symbol->sectionID != -1)
nbSymPerSect[symbol->sectionID]++;
}
/* This file's sections, stored in a table to link symbols to them */
struct Section *fileSections[nbSections ? nbSections : 1];
verbosePrint("Reading %u sections...\n", nbSections);
for (uint32_t i = 0; i < nbSections; i++) {
/* Read section */
struct Section *section = malloc(sizeof(*section));
if (!section)
err(1, "%s: Couldn't create new section", fileName);
readSection(file, section, fileName);
section->fileSymbols = fileSymbols;
sect_AddSection(section);
fileSections[i] = section;
if (nbSymPerSect[i]) {
section->symbols = malloc(sizeof(*section->symbols)
* nbSymPerSect[i]);
if (!section->symbols)
err(1, "%s: Couldn't link to symbols",
fileName);
} else {
section->symbols = NULL;
}
section->nbSymbols = 0;
}
/* Give symbols pointers to their sections */
for (uint32_t i = 0; i < nbSymbols; i++) {
int32_t sectionID = fileSymbols[i]->sectionID;
if (sectionID == -1) {
fileSymbols[i]->section = NULL;
} else {
fileSymbols[i]->section = fileSections[sectionID];
/* Give the section a pointer to the symbol as well */
linkSymToSect(fileSymbols[i], fileSections[sectionID]);
}
}
fclose(file);
}
void obj_DoSanityChecks(void)
{
sect_DoSanityChecks();
}
static void freeSection(struct Section *section, void *arg)
{
(void)arg;
free(section->name);
if (sect_HasData(section->type)) {
free(section->data);
for (int32_t i = 0; i < section->nbPatches; i++) {
struct Patch *patch = §ion->patches[i];
free(patch->fileName);
free(patch->rpnExpression);
}
free(section->patches);
}
free(section->symbols);
free(section);
}
static void freeSymbol(struct Symbol *symbol)
{
free(symbol->name);
if (symbol->type != SYMTYPE_IMPORT)
free(symbol->fileName);
free(symbol);
}
void obj_Cleanup(void)
{
sym_CleanupSymbols();
sect_ForEach(freeSection, NULL);
sect_CleanupSections();
struct SymbolList *list = symbolLists;
while (list) {
for (size_t i = 0; i < list->nbSymbols; i++)
freeSymbol(list->symbolList[i]);
free(list->symbolList);
struct SymbolList *next = list->next;
free(list);
list = next;
}
}