refactor elf32 assembler, add support for multiple isa's in cmdline

masm/asm.h

@@ -1,99 +0,0 @@
-/* Copyright (c) 2024 Freya Murphy */
-
-#ifndef __ASM_H__
-#define __ASM_H__
-
-#include <elf.h>
-
-#include "gen.h"
-
-///
-/// ELF string table
-///
-
-struct elf_str_table {
-	// size of the ptr in bytes
-	size_t size;
-
-	// pointer that contains
-	// the strings
-	char *ptr;
-};
-
-/* initalize a string table */
-int strtab_init(struct elf_str_table *strtab);
-
-/* free a string table */
-void strtab_free(struct elf_str_table *strtab);
-
-/* get a string form the string table */
-int strtab_get_str(struct elf_str_table *strtab, const char *str, size_t *res);
-
-/* get or append a string into the string table */
-int strtab_write_str(struct elf_str_table *strtab, const char *str, size_t *res);
-
-///
-/// elf section
-///
-
-/* holds a section of the asm file (i.e. .text, .bss, .data) */
-struct elf_section {
-	// section data *weak* pointer
-	struct section *data;
-
-	// index of the section in
-	// the ELF shdr
-	size_t shdr_idx;
-
-	// relocation table
-	size_t reltab_shidx;
-	uint32_t reltab_len;
-	Elf32_Rel *reltab;
-};
-
-///
-/// assembler
-///
-
-struct assembler {
-	// the code generator
-	struct generator gen;
-
-	/// symbol table
-	size_t symtab_shidx;
-	size_t symtab_len;
-	Elf32_Sym *symbols;
-
-	// sh string table
-	size_t strtab_shidx;
-	struct elf_str_table strtab;
-
-	// string table
-	size_t shstrtab_shidx;
-	struct elf_str_table shstrtab;
-
-	/// sections
-	uint32_t section_len;
-	struct elf_section *sections;
-
-	/// section header
-	Elf32_Shdr *shdr;
-	uint32_t shdr_len;
-};
-
-/* defines arguments to the assembler */
-struct assembler_arguments {
-	char *in_file;
-	char *out_file;
-};
-
-/* initalize the assembler */
-int assembler_init(struct assembler *assembler, const char *path);
-
-/* free the assembler */
-void assembler_free(struct assembler *assembler);
-
-/* assemble a file */
-int assemble_file(struct assembler_arguments args);
-
-#endif /* __ASM_H__ */

masm/asm/elf32.c

@@ -1,15 +1,11 @@
 #include <merror.h>
-#include <netinet/in.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <elf.h>
-#include <string.h>
-#include <stddef.h>
 #include <melf.h>
 
-#include "asm.h"
+#include "../tab.h"
-#include "gen.h"
+#include "../masm.h"
-#include "tab.h"
+#include "elf32.h"
 
 extern char *current_file;
 
@@ -83,10 +79,10 @@ static void elf_section_free(struct elf_section *sec)
 		free(sec->reltab);
 }
 
-static int asm_init_sections(struct assembler *assembler)
+static int asm_init_sections(struct elf_assembler *assembler)
 {
-	struct section *sections = assembler->gen.sections;
+	struct section *sections = assembler->gen->sections;
-	uint32_t len = assembler->gen.sections_len;
+	uint32_t len = assembler->gen->sections_len;
 
 	struct elf_section *elftab = malloc(sizeof(struct elf_section) * len);
 	if (elftab == NULL) {
@@ -121,8 +117,8 @@ static int elf_sym_bind(enum symbol_type ty) {
 	return STB_GLOBAL;
 }
 
-static int asm_init_symtab(struct assembler *assembler) {
+static int asm_init_symtab(struct elf_assembler *assembler) {
-	struct symbol_table *symtab = &assembler->gen.symtab;
+	struct symbol_table *symtab = &assembler->gen->symtab;
 	size_t len = symtab->len + 1;
 	Elf32_Sym *elftab = malloc(sizeof(Elf32_Sym) * len);
 	if (elftab == NULL) {
@@ -146,6 +142,17 @@ static int asm_init_symtab(struct assembler *assembler) {
 			return M_ERROR;
 		}
 
+		// check if symbol is undefined
+		if (sym->secidx == SYM_SEC_STUB) {
+			if (sym->type == SYM_LOCAL &&
+				assembler->args->extern_undefined == false) {
+				ERROR("undefined symbol %s", sym->name.str);
+				return M_ERROR;
+			}
+			sym->secidx = 0;
+			bind = STB_GLOBAL;
+		}
+
 		elftab[i+1] = (Elf32_Sym) {
 			.st_name = B32(str_off),
 			.st_info = ELF32_ST_INFO(bind, type),
@@ -162,18 +169,7 @@ static int asm_init_symtab(struct assembler *assembler) {
 	return M_SUCCESS;
 }
 
-static int parse_file(struct assembler *assembler)
+static int assemble_shdr(struct elf_assembler *assembler, Elf32_Shdr **res,
-{
-	if (generate_mips32r6(&assembler->gen))
-		return M_ERROR;
-	if (asm_init_sections(assembler))
-		return M_ERROR;
-	if (asm_init_symtab(assembler))
-		return M_ERROR;
-	return M_SUCCESS;
-}
-
-static int assemble_shdr(struct assembler *assembler, Elf32_Shdr **res,
 			 uint32_t *res2)
 {
 	uint32_t max_entries = 0;
@@ -337,7 +333,7 @@ static int assemble_shdr(struct assembler *assembler, Elf32_Shdr **res,
 	return M_SUCCESS;
 }
 
-static void update_offsets(struct assembler *assembler, Elf32_Ehdr *ehdr)
+static void update_offsets(struct elf_assembler *assembler, Elf32_Ehdr *ehdr)
 {
 	Elf32_Shdr *shdr = (Elf32_Shdr *) assembler->shdr;
 	uint32_t ptr = 0;
@@ -402,7 +398,7 @@ static void update_offsets(struct assembler *assembler, Elf32_Ehdr *ehdr)
 	ehdr->e_shoff = B32(ptr);
 }
 
-static int write_file(struct assembler *assembler, Elf32_Ehdr *ehdr,
+static int write_file(struct elf_assembler *assembler, Elf32_Ehdr *ehdr,
 		       const char *path)
 {
 	FILE *out = fopen(path, "w");
@@ -453,11 +449,11 @@ static int write_file(struct assembler *assembler, Elf32_Ehdr *ehdr,
 	return M_SUCCESS;
 }
 
-static void update_sym_shndx(struct assembler *assembler)
+static void update_sym_shndx(struct elf_assembler *assembler)
 {
 	for (uint32_t i = 1; i < assembler->symtab_len; i++) {
 		Elf32_Sym *esym = &assembler->symbols[i];
-		struct symbol *sym = &assembler->gen.symtab.symbols[i - 1];
+		struct symbol *sym = &assembler->gen->symtab.symbols[i - 1];
 
 		// get shindx
 		int shindx = 0;
@@ -470,14 +466,42 @@ static void update_sym_shndx(struct assembler *assembler)
 	}
 }
 
-static int assemble_elf(struct assembler *assembler, const char *out)
+static int assemble_elf(struct elf_assembler *assembler, const char *out)
 {
+	if (asm_init_sections(assembler))
+		return M_ERROR;
+
+	if (asm_init_symtab(assembler))
+		return M_ERROR;
+
 	if (assemble_shdr(assembler, &assembler->shdr, &assembler->shdr_len))
 		return M_ERROR;
 
+	// get ehdr flags
+	uint32_t flags = EF_MIPS_NAN2008;
+	switch (assembler->args->isa) {
+        case ISA_MIPS1:
+		flags |= EF_MIPS_ARCH_1;
+		break;
+        case ISA_MIPS32R2:
+		flags |= EF_MIPS_ARCH_32R2;
+		break;
+        case ISA_MIPS32R6:
+		flags |= EF_MIPS_ARCH_32R6;
+		break;
+        }
+	switch (assembler->args->abi) {
+	case ABI_O32:
+		flags |= EF_MIPS_ABI_O32;
+		break;
+	case ABI_NONE:
+		break;
+	}
+
 	Elf32_Ehdr ehdr = MIPS_ELF_EHDR;
 	ehdr.e_shnum = B16(assembler->shdr_len);
 	ehdr.e_shstrndx = B16(assembler->shstrtab_shidx);
+	ehdr.e_flags = B32(flags);
 	update_offsets(assembler, &ehdr);
 	update_sym_shndx(assembler);
 
@@ -487,41 +511,20 @@ static int assemble_elf(struct assembler *assembler, const char *out)
 	return M_SUCCESS;
 }
 
-int assemble_file(struct assembler_arguments args)
+static int assembler_init(struct elf_assembler *assembler,
+			  struct generator *gen,
+			  struct arguments *args)
 {
-	struct assembler assembler;
+	assembler->args = args;
-	int res = M_SUCCESS;
+	assembler->gen = gen;
 
-	current_file = args.in_file;
-
-	if (assembler_init(&assembler, args.in_file))
-		return M_ERROR;
-
-	if (res == M_SUCCESS)
-		res = parse_file(&assembler);
-
-	if (res == M_SUCCESS)
-		res = assemble_elf(&assembler, args.out_file);
-
-	assembler_free(&assembler);
-
-	return res;
-}
-
-int assembler_init(struct assembler *assembler, const char *path)
-{
 	assembler->shdr = NULL;
 	assembler->symbols = NULL;
 	assembler->sections = NULL;
 	assembler->strtab.ptr = NULL;
 	assembler->shstrtab.ptr = NULL;
-	assembler->gen.sections = NULL;
-	assembler->gen.symtab.symbols = NULL;
 	assembler->section_len = 0;
 
-	if (generator_init(path, &assembler->gen))
-		return M_ERROR;
-
 	if (strtab_init(&assembler->shstrtab))
 		return M_ERROR;
 
@@ -531,7 +534,7 @@ int assembler_init(struct assembler *assembler, const char *path)
 	return M_SUCCESS;
 }
 
-void assembler_free(struct assembler *assembler)
+static void assembler_free(struct elf_assembler *assembler)
 {
 	if (assembler->shdr)
 		free(assembler->shdr);
@@ -545,5 +548,20 @@ void assembler_free(struct assembler *assembler)
 
 	strtab_free(&assembler->strtab);
 	strtab_free(&assembler->shstrtab);
-	generator_free(&assembler->gen);
 }
+
+int assemble_elf32(struct generator *gen, struct arguments *args)
+{
+	struct elf_assembler assembler;
+	int res = M_SUCCESS;
+	current_file = args->in_file;
+
+	if (assembler_init(&assembler, gen, args))
+		return M_ERROR;
+
+	res = assemble_elf(&assembler, args->out_file);
+	assembler_free(&assembler);
+
+	return res;
+}
+

masm/asm/elf32.h

@@ -0,0 +1,90 @@
+/* Copyright (c) 2024 Freya Murphy */
+
+#ifndef __ELF32_H__
+#define __ELF32_H__
+
+#include <elf.h>
+
+#include "../gen.h"
+#include "../masm.h"
+
+///
+/// ELF string table
+///
+
+struct elf_str_table {
+	// size of the ptr in bytes
+	size_t size;
+
+	// pointer that contains
+	// the strings
+	char *ptr;
+};
+
+/* initalize a string table */
+int strtab_init(struct elf_str_table *strtab);
+
+/* free a string table */
+void strtab_free(struct elf_str_table *strtab);
+
+/* get a string form the string table */
+int strtab_get_str(struct elf_str_table *strtab, const char *str, size_t *res);
+
+/* get or append a string into the string table */
+int strtab_write_str(struct elf_str_table *strtab, const char *str, size_t *res);
+
+///
+/// elf section
+///
+
+/* holds a section of the asm file (i.e. .text, .bss, .data) */
+struct elf_section {
+	// section data *weak* pointer
+	struct section *data;
+
+	// index of the section in
+	// the ELF shdr
+	size_t shdr_idx;
+
+	// relocation table
+	size_t reltab_shidx;
+	uint32_t reltab_len;
+	Elf32_Rel *reltab;
+};
+
+///
+/// assembler
+///
+
+struct elf_assembler {
+	// arguments passed in
+	struct arguments *args;
+
+	// the code generator
+	struct generator *gen;
+
+	/// symbol table
+	size_t symtab_shidx;
+	size_t symtab_len;
+	Elf32_Sym *symbols;
+
+	// sh string table
+	size_t strtab_shidx;
+	struct elf_str_table strtab;
+
+	// string table
+	size_t shstrtab_shidx;
+	struct elf_str_table shstrtab;
+
+	/// sections
+	uint32_t section_len;
+	struct elf_section *sections;
+
+	/// section header
+	Elf32_Shdr *shdr;
+	uint32_t shdr_len;
+};
+
+int assemble_elf32(struct generator *gen, struct arguments *args);
+
+#endif /* __ELF32_H__ */

masm/asm/strtab.c

@@ -2,7 +2,7 @@
 #include <string.h>
 #include <stdlib.h>
 
-#include "asm.h"
+#include "elf32.h"
 
 int strtab_get_str(struct elf_str_table *strtab, const char *str, size_t *res)
 {

masm/main.c

@@ -1,33 +1,151 @@
 #include <unistd.h>
 #include <merror.h>
 #include <string.h>
+#include <stdio.h>
 
-#include "asm.h"
+#include "gen.h"
+#include "masm.h"
+#include "asm/elf32.h"
 
 void help(void) {
-	printf("usage: masm [options] source.asm\n\n");
+	printf(
-	printf("options:\n");
+"usage: masm [options] source.asm\n"
-	printf("\t-h\t\tprints this help message\n");
+"\n"
-	printf("\t-o <output>\tselect a output file destination\n");
+"options: \n"
+"	-h		print the help message \n"
+"	-g		assume undefined symbols are external\n"
+"	-o <output>	specify the object file output name \n"
+"	-a <abi>	specify mips abi used [none, o32] \n"
+"			default: o32 \n"
+"	-i <isa>	mips machine isa to assemble for [mips1, mips32r2, mips32r6] \n"
+"			default: mips32r6\n"
+"	-f <format>	specify the object file format [elf32] \n"
+"			defualt: elf32\n"
+	);
+}
+
+static int read_isa(enum isa *isa, const char *str)
+{
+	#define __ISA_CHK(name) \
+		if (strcasecmp(#name, str) == 0) { \
+			*isa = ISA_ ##name; \
+			return M_SUCCESS; \
+		} \
+
+	__ISA_CHK(MIPS1);
+	__ISA_CHK(MIPS32R2);
+	__ISA_CHK(MIPS32R6);
+
+	ERROR("invalid isa '%s'", str);
+	return M_ERROR;
+}
+
+static int read_abi(enum abi *abi, const char *str)
+{
+	#define __ABI_CHK(name) \
+		if (strcasecmp(#name, str) == 0) { \
+			*abi = ABI_ ##name; \
+			return M_SUCCESS; \
+		} \
+
+
+	__ABI_CHK(O32);
+	__ABI_CHK(NONE);
+
+	ERROR("invalid abi '%s'", str);
+	return M_ERROR;
+}
+
+static int read_format(enum format *format, const char *str)
+{
+	#define __FORMAT_CHK(name) \
+		if (strcasecmp(#name, str) == 0) { \
+			*format = FORMAT_ ##name; \
+			return M_SUCCESS; \
+		} \
+
+
+	__FORMAT_CHK(ELF32);
+
+	ERROR("invalid format '%s'", str);
+	return M_ERROR;
+}
+
+static int generate(struct generator *gen, struct arguments *args)
+{
+	if (generator_init(args->in_file, gen))
+		return M_ERROR;
+
+	switch (args->isa) {
+        case ISA_MIPS1:
+		return generate_mips1(gen);
+        case ISA_MIPS32R2:
+		return generate_mips32r2(gen);
+        case ISA_MIPS32R6:
+		return generate_mips32r6(gen);
+        }
+
+	return M_ERROR;
+}
+
+static int assemble(struct arguments *args)
+{
+	struct generator gen;
+	int res = M_SUCCESS;
+
+	if (generate(&gen, args))
+		return M_ERROR;
+
+	switch (args->format) {
+        case FORMAT_ELF32:
+		res = assemble_elf32(&gen, args);
+		break;
+	default:
+		res = M_ERROR;
+		break;
+        }
+
+	generator_free(&gen);
+
+	return res;
 }
 
 int main(int argc, char **argv) {
 
-	struct assembler_arguments args = {
+	struct arguments args = {
 		.in_file = NULL,
 		.out_file = "out.o",
+		.extern_undefined = false,
+		.isa = ISA_MIPS32R6,
+		.abi = ABI_O32,
+		.format = FORMAT_ELF32
 	};
 
 	int c;
 
-	while ((c = getopt(argc, argv, "ho:")) != 1) {
+	while ((c = getopt(argc, argv, "hgo:a:i:f:")) != 1) {
 		switch(c) {
 		case 'h':
 			help();
 			return M_SUCCESS;
+		case 'g':
+			args.extern_undefined = true;
+			break;
 		case 'o':
 			args.out_file = optarg;
 			break;
+		case 'a':
+			if (read_abi(&args.abi, optarg))
+				return M_ERROR;
+			break;
+		case 'i':
+			if (read_isa(&args.isa, optarg))
+				return M_ERROR;
+			break;
+		case 'f':
+			if (read_format(&args.format, optarg))
+				return M_ERROR;
+			break;
 		case '?':
 			return M_ERROR;
 		default:
@@ -48,5 +166,5 @@ next:
 
 	args.in_file = argv[optind];
 
-	return assemble_file(args);
+	return assemble(&args);
 }

masm/masm.h

@@ -0,0 +1,45 @@
+/* Copyright (c) 2024 Freya Murphy */
+
+#ifndef __MASM_H__
+#define __MASM_H__
+
+// isa to asemble for
+enum isa {
+	ISA_MIPS1, // a.k.a mipsR2000
+	ISA_MIPS32R2,
+	ISA_MIPS32R6,
+};
+
+// abi to mark output object
+enum abi {
+	ABI_O32, // mips o32 abi
+	ABI_NONE, // no flag output
+};
+
+// format for the object file
+enum format {
+	FORMAT_ELF32,
+};
+
+// defines arguments
+struct arguments {
+	// files to read from and
+	// write to
+	char *in_file;
+	char *out_file;
+
+	// if undefined symbols should
+	// be treated as extern
+	bool extern_undefined;
+
+	// isa to assemble for
+	enum isa isa;
+
+	// abi to mark object
+	enum abi abi;
+
+	// format to output
+	enum format format;
+};
+
+#endif /* __ASM_H__ */