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Remove relocation data in dwarf_write

This commit is contained in:
Théophile Bastian 2018-12-23 15:36:24 +01:00
parent effccb087e
commit 828abdf495
6 changed files with 74 additions and 12 deletions
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4
DwarfSynth/PreCBinding.ml
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@ -68,9 +68,9 @@ let convert_pre_c_entries entries : pre_c_pre_dwarf_entry array =
(fun loc entry _ -> convert_pre_c_entry loc entry)
entries empty_entry
let convert_pre_c_fde name entry num : pre_c_pre_dwarf_fde =
let convert_pre_c_fde name entry id : pre_c_pre_dwarf_fde =
{
num = num;
num = AddrMap.cardinal entry.cfa_changes_fde;
initial_location = entry.beg_pos;
end_location = entry.end_pos;
name = name;

3
DwarfSynth/c_bindings/.gitignore vendored Normal file
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@ -0,0 +1,3 @@
*.o
*.bin
*.bck

15
DwarfSynth/c_bindings/Makefile Normal file
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@ -0,0 +1,15 @@
CDEFINE =
CFLAGS = -Wall -Wextra -std=c11 -O2 -g $(CDEFINE)
LIBDWARFW_DIR=../../libdwarfw/build
CLIBS = -L$(LIBDWARFW_DIR) -Wl,-rpath,$(LIBDWARFW_DIR) -lelf -ldwarf -ldwarfw
all: test_dw.bin
test_%.bin: test_%.o dwarf_write.o
gcc $(CFLAGS) $(CLIBS) $^ -o $@
%.o: %.c
gcc $(CFLAGS) -c $< -o $@
clean:
rm -f *.o test_*.bin

41
DwarfSynth/c_bindings/dwarf_write.c
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@ -6,6 +6,7 @@
#include "dwarf_write.h"
struct internal_state {
Elf *elf;
};
@ -255,10 +256,11 @@ static int write_all_fde_instructions(struct dwarfw_fde *fde,
}
static int process_section(struct internal_state* state,
struct pre_dwarf* pre_dwarf, Elf_Scn *s, FILE *f, size_t *written,
FILE *rela_f)
struct pre_dwarf* pre_dwarf, Elf_Scn *s, FILE *f, size_t *written /*,
FILE *rela_f */)
{
size_t shndx = elf_ndxscn(s);
fprintf(stderr, "Processing section %lu\n", shndx); //D
GElf_Sym text_sym;
int text_sym_idx = find_section_symbol(state->elf, shndx, &text_sym);
@ -267,6 +269,12 @@ static int process_section(struct internal_state* state,
return 1;
}
GElf_Shdr shdr;
gelf_getshdr(s, &shdr);
uintptr_t s_addr = shdr.sh_addr,
s_endaddr = shdr.sh_addr + shdr.sh_size;
struct dwarfw_cie cie = {
.version = 1,
.augmentation = "zR",
@ -274,7 +282,7 @@ static int process_section(struct internal_state* state,
.data_alignment = -8,
.return_address_register = 16,
.augmentation_data = {
.pointer_encoding = DW_EH_PE_sdata4 | DW_EH_PE_pcrel,
.pointer_encoding = DW_EH_PE_sdata4 /* | DW_EH_PE_pcrel */,
},
};
@ -289,6 +297,14 @@ static int process_section(struct internal_state* state,
for (size_t fde_id = 0; fde_id < pre_dwarf->num_fde; ++fde_id) {
struct pre_dwarf_fde* cur_fde = &(pre_dwarf->fdes[fde_id]);
if(!(s_addr <= cur_fde->initial_location
&& cur_fde->end_location < s_endaddr))
// The fde is not included in this section
{
continue;
}
fprintf(stderr, "FDE %lu belongs to this section\n", cur_fde->num); //D
struct dwarfw_fde fde = {
.cie = &cie,
.initial_location = cur_fde->initial_location,
@ -317,16 +333,17 @@ static int process_section(struct internal_state* state,
fde.instructions = instr_buf;
fde.cie_pointer = *written;
GElf_Rela initial_position_rela;
if (!(n = dwarfw_fde_write(&fde, &initial_position_rela, f))) {
/* GElf_Rela initial_position_rela; */
if (!(n = dwarfw_fde_write(&fde, /*&initial_position_rela*/NULL, f))) {
fprintf(stderr, "dwarfw_fde_write() failed\n");
return -1;
}
initial_position_rela.r_offset += *written;
/* initial_position_rela.r_offset += *written; */
*written += n;
free(instr_buf);
// r_offset and r_addend have already been populated by dwarfw_fde_write
/*
initial_position_rela.r_info = GELF_R_INFO(text_sym_idx,
ELF32_R_TYPE(initial_position_rela.r_info));
@ -334,6 +351,7 @@ static int process_section(struct internal_state* state,
fprintf(stderr, "can't write rela\n");
return 1;
}
*/
}
return 0;
@ -382,6 +400,7 @@ int write_dwarf(char* objname, struct pre_dwarf* pre_dwarf) {
return 1;
}
/*
char *rela_buf;
size_t rela_len;
FILE *rela_f = open_memstream(&rela_buf, &rela_len);
@ -389,6 +408,7 @@ int write_dwarf(char* objname, struct pre_dwarf* pre_dwarf) {
fprintf(stderr, "open_memstream() failed\n");
return 1;
}
*/
size_t written = 0;
for (size_t i = 0; i < sections_num; ++i) {
@ -406,13 +426,12 @@ int write_dwarf(char* objname, struct pre_dwarf* pre_dwarf) {
continue;
}
if (process_section(&state, pre_dwarf, s, f, &written, rela_f)) {
if (process_section(&state, pre_dwarf, s, f, &written /*, rela_f*/)) {
return 1;
}
}
fclose(f);
fclose(rela_f);
/* fclose(rela_f); */
// Create the .eh_frame section
Elf_Scn *scn = create_debug_frame_section(elf, ".eh_frame", buf, len);
@ -421,6 +440,7 @@ int write_dwarf(char* objname, struct pre_dwarf* pre_dwarf) {
return 1;
}
/*
// Create the .eh_frame.rela section
Elf_Scn *rela = create_rela_section(elf, ".rela.eh_frame", scn,
rela_buf, rela_len);
@ -428,6 +448,7 @@ int write_dwarf(char* objname, struct pre_dwarf* pre_dwarf) {
fprintf(stderr, "create_rela_section() failed\n");
return 1;
}
*/
// Write the modified ELF object
elf_flagelf(elf, ELF_C_SET, ELF_F_DIRTY);
@ -437,7 +458,7 @@ int write_dwarf(char* objname, struct pre_dwarf* pre_dwarf) {
}
free(buf);
free(rela_buf);
/* free(rela_buf); */
elf_end(elf);
close(fd);

5
DwarfSynth/c_bindings/dwarf_write.h
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@ -6,6 +6,8 @@
#pragma once
#define _XOPEN_SOURCE 700
#include "../../libdwarfw/include/dwarfw.h"
#include <dwarf.h>
@ -52,3 +54,6 @@ struct pre_dwarf {
size_t num_fde;
struct pre_dwarf_fde* fdes;
};
/// Writes the provided `pre_dwarf` as DWARF in the ELF file at `obj_path`
int write_dwarf(char* obj_path, struct pre_dwarf* pre_dwarf);

18
DwarfSynth/c_bindings/test_dw.c Normal file
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@ -0,0 +1,18 @@
#include <stdlib.h>
#include <stdio.h>
#include "dwarf_write.h"
int main() {
struct pre_dwarf_entry entries[3] = {
{ 0x1300, DW_REG_RSP, 8 },
{ 0x1310, DW_REG_RSP, 16 },
{ 0x1340, DW_REG_RSP, 8 }
};
struct pre_dwarf_fde fde = {
3, entries, 0x1300, 0x1342
};
struct pre_dwarf dwarf_data = {1, &fde};
write_dwarf("test.bin", &dwarf_data);
return 0;
}