Remove relocation data in dwarf_write

DwarfSynth/PreCBinding.ml

@@ -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;

DwarfSynth/c_bindings/.gitignore

@@ -0,0 +1,3 @@
+*.o
+*.bin
+*.bck

DwarfSynth/c_bindings/Makefile

@@ -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

DwarfSynth/c_bindings/dwarf_write.c

@@ -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,
+        struct pre_dwarf* pre_dwarf, Elf_Scn *s, FILE *f, size_t *written /*,
-        FILE *rela_f)
+        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;
+		/* GElf_Rela initial_position_rela; */
-		if (!(n = dwarfw_fde_write(&fde, &initial_position_rela, f))) {
+		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);

DwarfSynth/c_bindings/dwarf_write.h

@@ -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);

DwarfSynth/c_bindings/test_dw.c

@@ -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;
+}