ref: 3c304f3acf5ff914ec3b1c8faacbc4c39c32ef36
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/assign.h" #include "link/main.h" #include "link/object.h" #include "link/patch.h" #include "link/section.h" #include "link/symbol.h" #include "extern/err.h" #include "helpers.h" #include "linkdefs.h" static struct SymbolList { size_t nbSymbols; struct Symbol **symbolList; struct SymbolList *next; } *symbolLists; static struct Assertion *assertions; /***** 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 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; uint8_t type; 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(type, file, "%s: Cannot read \"%s\"'s type: %s", fileName, section->name); section->type = type & 0x7F; section->isUnion = type >> 7; 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 assertion from a file * @param file The file to read from * @param assert The struct to fill * @param fileName The filename to report in errors */ static void readAssertion(FILE *file, struct Assertion *assert, char const *fileName, struct Section *fileSections[], uint32_t i) { char assertName[sizeof("Assertion #" EXPAND_AND_STR(UINT32_MAX))]; uint32_t sectionID; snprintf(assertName, sizeof(assertName), "Assertion #%u", i); readPatch(file, &assert->patch, fileName, assertName, 0); tryReadlong(sectionID, file, "%s: Cannot read assertion's section ID: %s", fileName); assert->section = fileSections[sectionID]; tryReadstr(assert->message, file, "%s: Cannot read assertion's message: %s", fileName); } static inline struct Section *getMainSection(struct Section *section) { if (section->isUnion) section = sect_GetSection(section->name); return section; } /** * 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); section->nextu = NULL; 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 { /* Give the section a pointer to the symbol as well */ linkSymToSect(fileSymbols[i], fileSections[sectionID]); fileSymbols[i]->section = getMainSection(fileSections[sectionID]); } } uint32_t nbAsserts; tryReadlong(nbAsserts, file, "%s: Cannot read number of assertions: %s", fileName); verbosePrint("Reading %u assertions...\n", nbAsserts); for (uint32_t i = 0; i < nbAsserts; i++) { struct Assertion *assertion = malloc(sizeof(*assertion)); if (!assertion) err(1, "%s: Couldn't create new assertion", fileName); readAssertion(file, assertion, fileName, fileSections, i); assertion->next = assertions; assertions = assertion; } fclose(file); } void obj_DoSanityChecks(void) { sect_DoSanityChecks(); patch_CheckAssertions(assertions); } 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; } }