mcc
mcc is a machine code compiler.
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tree 032e7e781efba089e274a03ae64527fd510bb234 parent 7b0311ce9e7911f97dae234121f11ac99e9db5d1 author esote <esote.net@gmail.com> 1558060688 -0500 committer esote <esote.net@gmail.com> 1558060688 -0500 gpgsig -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTXAxYDuIzimYoNSPuhTmRAjzzC8gUCXSArFAAKCRChTmRAjzzC 8jj7APwLlqLXCd1kk3KmT2WTvb+piJ6QtgD4XexZWSmfElpGSwEAxxCMiB2jEixe +IT4URB3sWn7slSnNho1Xb43Um6Eqwg= =OYWI -----END PGP SIGNATURE----- Trim positioning of program and section hdrs
mcc.c | 32 +++++++++++++------------------- 1 file changed, 13 insertions(+), 19 deletions(-)
diff --git a/mcc.c b/mcc.c
index 6231539..0ebe80f 100644
--- a/mcc.c
+++ b/mcc.c
@@ -117,13 +117,6 @@ main(int argc, char *argv[])
write_elf_hdr(out, len);
- /* TODO magic */
- for (i = 0; i < 12; ++i) {
- if (fwrite(&zero, 1, 1, out) != 1) {
- err(1, "write zero trailing elf hdr");
- }
- }
-
write_text_hdr(out, len);
write_bss_hdr(out, mem);
@@ -223,20 +216,22 @@ write_elf_hdr(FILE *const out, uint32_t const len)
e.e_version = EV_CURRENT;
e.e_flags = 0;
- /* TODO magic */
- e.e_entry = TEXT_VADDR + 0x80;
e.e_ehsize = sizeof(Elf32_Ehdr);
-
- e.e_phnum = 2;
e.e_phentsize = sizeof(Elf32_Phdr);
- e.e_phoff = e.e_phnum * e.e_phentsize;
-
- e.e_shnum = 4;
e.e_shentsize = sizeof(Elf32_Shdr);
- e.e_shoff = e.e_shnum * e.e_shentsize + len;
+ e.e_phnum = 2;
+ e.e_shnum = 4;
e.e_shstrndx = 3;
+ /* program hdrs start after elf hdr */
+ e.e_phoff = e.e_ehsize;
+
+ e.e_entry = TEXT_VADDR + e.e_ehsize + e.e_phnum * e.e_phentsize;
+
+ /* section hdrs start after elf hdr, program hdrs, text, and shstrtab */
+ e.e_shoff = e.e_ehsize + e.e_phnum * e.e_phentsize + len + 32;
+
if (fwrite(&e, sizeof(Elf32_Ehdr), 1, out) != 1) {
err(1, "write elf hdr");
}
@@ -365,9 +360,8 @@ write_text_section(FILE *const out, uint32_t const len)
text.sh_name = TEXT_INDEX;
text.sh_type = SHT_PROGBITS;
text.sh_flags = SHF_ALLOC | SHF_EXECINSTR;
- /* TODO magic */
- text.sh_addr = TEXT_VADDR + 0x80;
- text.sh_offset = 0x80;
+ text.sh_addr = TEXT_VADDR + sizeof(Elf32_Ehdr) + 2 * sizeof(Elf32_Phdr);
+ text.sh_offset = sizeof(Elf32_Ehdr) + 2 * sizeof(Elf32_Phdr);
text.sh_size = len;
text.sh_link = 0;
text.sh_info = 0;
@@ -411,7 +405,7 @@ write_shstrtab_section(FILE *const out, uint32_t const len)
shstrtab.sh_flags = 0;
shstrtab.sh_addr = 0;
/* TODO magic */
- shstrtab.sh_offset = 128 + len;
+ shstrtab.sh_offset = sizeof(Elf32_Ehdr) + 2*sizeof(Elf32_Phdr) + len;
shstrtab.sh_size = NULL_LEN + SHSTRTAB_LEN + TEXT_LEN + BSS_LEN;
shstrtab.sh_link = 0;
shstrtab.sh_info = 0;