moved eh_frame files to dwarf layer

This commit is contained in:
Nikita Smith
2025-11-07 14:39:45 -08:00
committed by Ryan Fleury
parent 78f2e641bc
commit 36b22c06b1
4 changed files with 776 additions and 0 deletions
+141
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// Copyright (c) Epic Games Tools
// Licensed under the MIT license (https://opensource.org/license/mit/)
internal String8List
eh_dump_list_from_data(Arena *arena, Arch arch, U64 eh_frame_hdr_vaddr, U64 eh_frame_vaddr, String8 eh_frame_hdr, String8 eh_frame, EH_DumpSubsetFlags subset_flags)
{
Temp scratch = scratch_begin(&arena, 1);
String8List strings = {0};
#define dumpf(...) str8_list_pushf(arena, &strings, __VA_ARGS__)
EH_PtrCtx ptr_ctx = { .data_vaddr = eh_frame_hdr_vaddr };
EH_FrameHdr hdr = eh_parse_frame_hdr(eh_frame_hdr, byte_size_from_arch(arch), &ptr_ctx);
DW_Ext ext = DW_Ext_All;
if (subset_flags & EH_DumpSubsetFlag_EhFrameHdr) {
dumpf("eh_frame_hdr:\n");
dumpf("{\n");
dumpf(" version: %u\n", hdr.version);
dumpf(" eh_frame_ptr_enc: %S\n", eh_string_from_ptr_enc(scratch.arena, hdr.eh_frame_ptr_enc));
dumpf(" table_enc: %S\n", eh_string_from_ptr_enc(scratch.arena, hdr.table_enc));
dumpf(" fde_count: %llu\n", hdr.fde_count);
if (hdr.eh_frame_ptr_enc != EH_PtrEnc_Omit) {
dumpf(" eh_frame_ptr: 0x%I64x\n", hdr.eh_frame_ptr);
}
dumpf(" Entries:\n");
dumpf(" {\n");
for (U64 cursor = 0; cursor < hdr.table.size; ) {
U64 entry_off = cursor;
U64 pc = 0;
U64 pc_size = eh_parse_ptr(hdr.table, cursor, cursor, &ptr_ctx, hdr.table_enc, &pc);
if (pc_size == 0) { break; }
cursor += pc_size;
U64 fde_addr = 0;
U64 fde_addr_size = eh_parse_ptr(hdr.table, cursor, cursor, &ptr_ctx, hdr.table_enc, &fde_addr);
if (fde_addr_size == 0) { break; }
cursor += fde_addr_size;
U64 fde_offset = fde_addr - eh_frame_vaddr;
dumpf(" { off=0x%04I64x, pc=0x%I64x, fde=0x%I64x }\n", entry_off, pc, fde_offset);
}
dumpf(" }\n");
dumpf("}\n");
}
if (subset_flags & EH_DumpSubsetFlag_EhFrame) {
dumpf(".eh_frame:\n");
dumpf("{\n");
for (U64 cursor = 0; cursor < eh_frame.size; ) {
DW_DescriptorEntry desc = {0};
U64 desc_size = eh_parse_descriptor_entry_header(eh_frame, cursor, &desc);
if (desc_size == 0) { break; }
switch (desc.type) {
case DW_DescriptorEntryType_Null: break;
case DW_DescriptorEntryType_CIE: {
String8 cie_data = str8_substr(eh_frame, desc.entry_range);
DW_CIE cie = {0};
if (eh_parse_cie(cie_data, desc.format, arch, eh_frame_vaddr + cursor, &ptr_ctx, &cie)) {
String8List init_insts_str_list = dw_string_list_from_cfi_program(scratch.arena, 0, arch, DW_Version_5, ext, cie.format, 0, &cie, eh_decode_ptr, &ptr_ctx, cie.insts);
dumpf(" CIE: // entry range: %r\n", desc.entry_range);
dumpf(" {\n");
dumpf(" Format: %S\n", dw_string_from_format(desc.format));
dumpf(" Version: %u\n", cie.version);
dumpf(" Aug string: \"%S\"\n", cie.aug_string);
dumpf(" Code align: %I64u\n", cie.code_align_factor);
dumpf(" Data align: %I64d\n", cie.data_align_factor);
dumpf(" Return addr reg: %u\n", cie.ret_addr_reg);
if (cie.version > DW_Version_3) {
dumpf(" Address size: %u\n", cie.address_size);
dumpf(" Segment selector size: %u\n", cie.segment_selector_size);
}
dumpf(" Initial Insturction:\n");
dumpf(" {\n");
for EachNode(n, String8Node, init_insts_str_list.first) { dumpf(" %S\n", n->string); }
dumpf(" }\n");
dumpf(" }\n");
} else {
dumpf("ERROR: unable to parse CIE @ %I64x\n", desc.entry_range.min);
}
} break;
case DW_DescriptorEntryType_FDE: {
U64 cie_offset = desc.cie_pointer_off - desc.cie_pointer;
DW_CIE cie = {0};
{
DW_DescriptorEntry cie_desc = {0};
eh_parse_descriptor_entry_header(eh_frame, cie_offset, &cie_desc);
if (cie_desc.type == DW_DescriptorEntryType_CIE) {
String8 cie_data = str8_substr(eh_frame, cie_desc.entry_range);
eh_parse_cie(cie_data, cie_desc.format, arch, eh_frame_vaddr + cie_offset, &ptr_ctx, &cie);
}
}
String8 fde_raw = str8_substr(eh_frame, desc.entry_range);
DW_FDE fde = {0};
if (eh_parse_fde(fde_raw, desc.format, eh_frame_vaddr + cursor, &cie, &ptr_ctx, &fde)) {
String8List insts_str_list = dw_string_list_from_cfi_program(scratch.arena, 0, arch, hdr.version, ext, fde.format, 0, &cie, eh_decode_ptr, &ptr_ctx, fde.insts);
dumpf(" FDE: // entry range: %r\n", desc.entry_range);
dumpf(" {\n");
{
dumpf(" Format: %S\n", dw_string_from_format(fde.format));
dumpf(" CIE: 0x%I64x\n", cie_offset);
dumpf(" PC range: %r\n", fde.pc_range);
dumpf(" Instructions:\n");
dumpf(" {\n");
for EachNode(n, String8Node, insts_str_list.first) { dumpf(" %S\n", n->string); }
dumpf(" }\n");
dumpf(" Unwind:\n");
dumpf(" {\n");
DW_CFI_Unwind *cfi_unwind = dw_cfi_unwind_init(scratch.arena, arch, &cie, &fde, eh_decode_ptr, &ptr_ctx);
do {
String8 cfa_str = dw_string_from_cfa(scratch.arena, arch, cie.address_size, hdr.version, ext, fde.format, cfi_unwind->row->cfa);
String8 cfi_row_str = dw_string_from_cfi_row(scratch.arena, arch, cie.address_size, hdr.version, ext, fde.format, cfi_unwind->row);
dumpf(" { PC: 0x%I64x, CFA: %-7S, Rules: { %S }\n", cfi_unwind->pc, cfa_str, cfi_row_str);
} while (dw_cfi_next_row(scratch.arena, cfi_unwind));
dumpf(" }\n");
}
} else {
dumpf("ERROR: unable to parse FDE @ %I64x\n", desc.entry_range.min);
}
dumpf(" }\n");
} break;
}
cursor += desc_size;
}
dumpf("}\n");
}
#undef dumpf
scratch_end(scratch);
return strings;
}
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// Copyright (c) Epic Games Tools
// Licensed under the MIT license (https://opensource.org/license/mit/)
#ifndef EH_FRAME_DUMP_H
#define EH_FRAME_DUMP_H
////////////////////////////////
//~ Dump Subset Types
#define EH_DumpSubset_XList \
X(EhFrameHdr, eh_frame_hdr, ".eh_frame_hdr") \
X(EhFrame, eh_frame, ".eh_frame")
typedef enum EH_DumpSubset {
#define X(name, name_lower, title) EH_DumpSubset_##name,
EH_DumpSubset_XList
#undef X
} EH_DumpSubset;
typedef U32 EH_DumpSubsetFlags;
enum {
#define X(name, name_lower, title) EH_DumpSubsetFlag_##name = (1<<EH_DumpSubset_##name),
EH_DumpSubset_XList
#undef X
EH_DumpSubsetFlag_All = 0xffffffff,
};
read_only global String8 eh_name_lowercase_from_dump_subset_table[] =
{
#define X(name, name_lower, title) str8_lit_comp(#name_lower),
EH_DumpSubset_XList
#undef X
};
read_only global String8 eh_name_title_from_dump_subset_table[] =
{
#define X(name, name_lower, title) str8_lit_comp(title),
EH_DumpSubset_XList
#undef X
};
////////////////////////////////
//~ Dump Entry Point
internal String8List eh_dump_list_from_data(Arena *arena, Arch arch, U64 eh_frame_hdr_vaddr, U64 eh_frame_vaddr, String8 eh_frame_hdr, String8 eh_frame, EH_DumpSubsetFlags subset_flags);
#endif // EH_FRAME_DUMP_H
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// Copyright (c) Epic Games Tools
// Licensed under the MIT license (https://opensource.org/license/mit/)
internal U64
eh_parse_ptr(String8 frame_base, U64 off, U64 pc, EH_PtrCtx *ptr_ctx, EH_PtrEnc encoding, U64 *ptr_out)
{
U64 ptr_off = off;
if (encoding == EH_PtrEnc_Omit) {
return 0;
}
// align read offset as needed
if (encoding == EH_PtrEnc_Aligned) {
ptr_off = AlignPow2(ptr_off, ptr_ctx->ptr_align);
encoding = EH_PtrEnc_Ptr;
}
// decode pointer value
U64 decode_size = 0;
U64 raw_ptr_size = 0;
U64 raw_ptr = 0;
switch (encoding & EH_PtrEnc_TypeMask) {
default: { InvalidPath; } break;
case EH_PtrEnc_Ptr : { raw_ptr_size = 8; } goto ufixed;
case EH_PtrEnc_UData2: { raw_ptr_size = 2; } goto ufixed;
case EH_PtrEnc_UData4: { raw_ptr_size = 4; } goto ufixed;
case EH_PtrEnc_UData8: { raw_ptr_size = 8; } goto ufixed;
ufixed: {
decode_size += str8_deserial_read(frame_base, ptr_off, &raw_ptr, raw_ptr_size, raw_ptr_size);
} break;
// TODO: Signed is actually just a flag that indicates this int is negavite.
// There shouldn't be a read for Signed.
// For instance, (EH_PtrEnc_UData2 | EH_PtrEnc_Signed) == EH_PtrEnc_SData etc.
case EH_PtrEnc_Signed: { raw_ptr_size = 8; } goto sfixed;
case EH_PtrEnc_SData2: { raw_ptr_size = 2; } goto sfixed;
case EH_PtrEnc_SData4: { raw_ptr_size = 4; } goto sfixed;
case EH_PtrEnc_SData8: { raw_ptr_size = 8; } goto sfixed;
sfixed: {
decode_size += str8_deserial_read(frame_base, ptr_off, &raw_ptr, raw_ptr_size, raw_ptr_size);
raw_ptr = extend_sign64(raw_ptr, raw_ptr_size);
} break;
case EH_PtrEnc_ULEB128: { decode_size += str8_deserial_read_uleb128(frame_base, ptr_off, &raw_ptr); } break;
case EH_PtrEnc_SLEB128: { decode_size += str8_deserial_read_sleb128(frame_base, ptr_off, (S64*)&raw_ptr); } break;
}
// apply relative bases
if (decode_size > 0) {
U64 ptr = raw_ptr;
switch (encoding & EH_PtrEnc_ModifierMask) {
case 0: break;
case EH_PtrEnc_PcRel: { ptr = pc + raw_ptr; } break;
case EH_PtrEnc_TextRel: { ptr = ptr_ctx->text_vaddr + raw_ptr; } break;
case EH_PtrEnc_DataRel: { ptr = ptr_ctx->data_vaddr + raw_ptr; } break;
case EH_PtrEnc_FuncRel: {
Assert(!"TODO: need a sample to verify implementation");
ptr = ptr_ctx->func_vaddr + raw_ptr;
} break;
default: { InvalidPath; } break;
}
if (ptr_out) {
*ptr_out = ptr;
}
}
return decode_size;
}
internal EH_FrameHdr
eh_parse_frame_hdr(String8 data, U64 address_size, EH_PtrCtx *ptr_ctx)
{
EH_FrameHdr header = {0};
U64 cursor = 0;
U64 version_size = str8_deserial_read_struct(data, cursor, &header.version);
if (version_size == 0) { goto exit; }
cursor += version_size;
if (header.version == 1) {
U64 eh_frame_ptr_enc_size = str8_deserial_read_struct(data, cursor, &header.eh_frame_ptr_enc);
if (eh_frame_ptr_enc_size == 0) { goto exit; }
cursor += eh_frame_ptr_enc_size;
U64 fde_count_enc_size = str8_deserial_read_struct(data, cursor, &header.fde_count_enc);
if (fde_count_enc_size == 0) { goto exit; }
cursor += fde_count_enc_size;
U64 table_enc_size = str8_deserial_read_struct(data, cursor, &header.table_enc);
if (table_enc_size == 0) { goto exit; }
cursor += table_enc_size;
cursor += eh_parse_ptr(data, cursor, cursor, ptr_ctx, header.eh_frame_ptr_enc, &header.eh_frame_ptr);
cursor += eh_parse_ptr(data, cursor, cursor, ptr_ctx, header.fde_count_enc, &header.fde_count);
switch (header.table_enc & EH_PtrEnc_TypeMask) {
case EH_PtrEnc_Ptr: { header.field_byte_size = address_size; } break;
case EH_PtrEnc_ULEB128: { InvalidPath; } break; // TODO: when loading module convert these to UData8
case EH_PtrEnc_UData2: { header.field_byte_size = 2; } break;
case EH_PtrEnc_UData4: { header.field_byte_size = 4; } break;
case EH_PtrEnc_UData8: { header.field_byte_size = 8; } break;
case EH_PtrEnc_Signed: { header.field_byte_size = address_size; } break;
case EH_PtrEnc_SLEB128: { InvalidPath; } break; // TODO: when loading module convert these to UData8
case EH_PtrEnc_SData2: { header.field_byte_size = 2; } break;
case EH_PtrEnc_SData4: { header.field_byte_size = 4; } break;
case EH_PtrEnc_SData8: { header.field_byte_size = 8; } break;
default: { InvalidPath; } break;
}
header.entry_byte_size = header.field_byte_size * 2;
header.table = str8_skip(data, cursor);
AssertAlways(header.table.size == header.entry_byte_size * header.fde_count);
} else {
Assert(0 && "unknown version");
}
exit:;
return header;
}
internal U64
eh_parse_aug_data(String8 aug_string, String8 aug_data, U64 pc, EH_PtrCtx *ptr_ctx, EH_Augmentation *aug_out)
{
// TODO:
// Handle "eh" param, it indicates presence of EH Data field.
// On 32bit arch it is a 4-byte and on 64-bit 8-byte value.
// Reference: https://refspecs.linuxfoundation.org/LSB_3.0.0/LSB-PDA/LSB-PDA/ehframechpt.html
// Reference doc doesn't clarify structure for EH Data though
U64 cursor = 0;
EH_AugFlags aug_flags = 0;
EH_PtrEnc lsda_encoding = EH_PtrEnc_Omit;
EH_PtrEnc addr_encoding = EH_PtrEnc_UData8;
EH_PtrEnc handler_encoding = EH_PtrEnc_Omit;
U64 handler_ip = 0;
if (str8_match(str8_prefix(aug_string, 1), str8_lit("z"), 0)) {
U64 aug_data_size = 0;
cursor = str8_deserial_read_uleb128(aug_data, cursor, &aug_data_size);
for (U8 *ptr = aug_string.str+1; ptr < (aug_string.str+aug_string.size); ptr += 1) {
switch (*ptr) {
case 'L': {
cursor += str8_deserial_read_struct(aug_data, cursor, &lsda_encoding);
aug_flags |= EH_AugFlag_HasLSDA;
} break;
case 'P': {
cursor += str8_deserial_read_struct(aug_data, cursor, &handler_encoding);
cursor += eh_parse_ptr(aug_data, cursor, pc + cursor, ptr_ctx, handler_encoding, &handler_ip);
aug_flags |= EH_AugFlag_HasHandler;
} break;
case 'R': {
cursor += str8_deserial_read_struct(aug_data, cursor, &addr_encoding);
aug_flags |= EH_AugFlag_HasAddrEnc;
} break;
default: { Assert(!"failed to parse augmentation string"); goto exit; } break;
}
}
}
if (aug_out) {
aug_out->handler_ip = handler_ip;
aug_out->handler_encoding = handler_encoding;
aug_out->lsda_encoding = handler_encoding;
aug_out->addr_encoding = addr_encoding;
aug_out->flags = aug_flags;
}
exit:;
U64 parse_size = cursor;
return parse_size;
}
internal U64
eh_parse_descriptor_entry_header(String8 data, U64 off, DW_DescriptorEntry *desc_out)
{
U32 first_four_bytes = 0;
str8_deserial_read_struct(data, off, &first_four_bytes);
DW_Format format = first_four_bytes == max_U32 ? DW_Format_64Bit : DW_Format_32Bit;
U64 length = 0;
U64 length_size = str8_deserial_read_dwarf_packed_size(data, off, &length);
if (length_size == 0) { goto exit; }
Rng1U64 entry_range = rng_1u64(off, off + length_size + length);
String8 entry_data = str8_substr(data, entry_range);
U64 id = 0;
U64 id_size = str8_deserial_read_dwarf_uint(entry_data, length_size, format, &id);
if (id_size == 0) { goto exit; }
desc_out->format = format;
desc_out->type = (id == 0) ? DW_DescriptorEntryType_CIE : DW_DescriptorEntryType_FDE;
desc_out->entry_range = entry_range;
desc_out->cie_pointer = id;
desc_out->cie_pointer_off = off + length_size;
exit:;
return length + length_size;
}
internal B32
eh_parse_cie(String8 data, DW_Format format, Arch arch, U64 pc, EH_PtrCtx *ptr_ctx, DW_CIE *cie_out)
{
B32 is_parsed = 0;
U64 cursor = format == DW_Format_32Bit ? 4 : 12;
U64 cie_id = 0;
U64 cie_id_size = str8_deserial_read_dwarf_uint(data, cursor, format, &cie_id);
if (cie_id_size == 0) { goto exit; }
cursor += cie_id_size;
U8 version = 0;
U64 version_size = str8_deserial_read_struct(data, cursor, &version);
if (version_size == 0) { goto exit; }
cursor += version_size;
String8 aug_string = {0};
EH_Augmentation aug = {0};
U64 code_align_factor = 0;
S64 data_align_factor = 0;
U64 ret_addr_reg = max_U64;
if (version == 1) {
U64 aug_string_size = str8_deserial_read_cstr(data, cursor, &aug_string);
if (aug_string_size == 0) { goto exit; }
cursor += aug_string_size;
U64 eh_data = 0;
if (str8_match(aug_string, str8_lit("eh"), 0)) {
U64 arch_byte_size = byte_size_from_arch(arch);
cursor += str8_deserial_read(data, cursor, &eh_data, arch_byte_size, arch_byte_size);
}
U64 code_align_factor_size = str8_deserial_read_uleb128(data, cursor, &code_align_factor);
if (code_align_factor_size == 0) { goto exit; }
cursor += code_align_factor_size;
U64 data_align_factor_size = str8_deserial_read_sleb128(data, cursor, &data_align_factor);
if (data_align_factor_size == 0) { goto exit; }
cursor += data_align_factor_size;
ret_addr_reg = 0;
U64 ret_addr_reg_size = str8_deserial_read(data, cursor, &ret_addr_reg, sizeof(U8), sizeof(U8));
if (ret_addr_reg_size == 0) { goto exit; }
cursor += ret_addr_reg_size;
U64 aug_data_size = eh_parse_aug_data(aug_string, str8_skip(data, cursor), pc + cursor, ptr_ctx, &aug);
cursor += aug_data_size;
}
cie_out->insts = str8_skip(data, cursor);
cie_out->aug_string = aug_string;
cie_out->code_align_factor = code_align_factor;
cie_out->data_align_factor = data_align_factor;
cie_out->ret_addr_reg = ret_addr_reg;
cie_out->format = format;
cie_out->version = version;
cie_out->address_size = byte_size_from_arch(arch);
cie_out->segment_selector_size = 0;
cie_out->ext[EH_CIE_Ext_LSDAEnc] = EH_PtrEnc_Omit;
cie_out->ext[EH_CIE_Ext_AddrEnc] = EH_PtrEnc_Omit;
cie_out->ext[EH_CIE_Ext_HandlerEnc] = EH_PtrEnc_Omit;
if (aug.flags & EH_AugFlag_HasLSDA) {
cie_out->ext[EH_CIE_Ext_LSDAEnc] = aug.lsda_encoding;
}
if (aug.flags & EH_AugFlag_HasAddrEnc) {
cie_out->ext[EH_CIE_Ext_AddrEnc] = aug.addr_encoding;
}
if (aug.flags & EH_AugFlag_HasHandler) {
cie_out->ext[EH_CIE_Ext_HandlerEnc] = aug.handler_encoding;
cie_out->ext[EH_CIE_Ext_HandlerIp ] = aug.handler_ip;
}
is_parsed = 1;
exit:;
return is_parsed;
}
internal B32
eh_parse_fde(String8 data, DW_Format format, U64 pc, DW_CIE *cie, EH_PtrCtx *ptr_ctx, DW_FDE *fde_out)
{
B32 is_parsed = 0;
U64 cursor = format == DW_Format_32Bit ? 8 : 20;
U64 pc_begin = 0;
U64 pc_delta = 0;
EH_PtrEnc addr_enc = cie->ext[EH_CIE_Ext_AddrEnc];
if (addr_enc != EH_PtrEnc_Omit) {
U64 pc_begin_size = eh_parse_ptr(data, cursor, pc + cursor, ptr_ctx, addr_enc, &pc_begin);
if (pc_begin_size == 0) { goto exit; }
cursor += pc_begin_size;
U64 pc_delta_size = eh_parse_ptr(data, cursor, pc + cursor, ptr_ctx, addr_enc & EH_PtrEnc_TypeMask, &pc_delta);
if (pc_delta_size == 0) { goto exit; }
cursor += pc_delta_size;
}
if (cursor + cie->aug_data.size > data.size) { goto exit; }
cursor += cie->aug_data.size;
fde_out->format = format;
fde_out->pc_range = rng_1u64(pc_begin, pc_begin + pc_delta);
fde_out->insts = str8_skip(data, cursor);
is_parsed = 1;
exit:;
return is_parsed;
}
internal U64
eh_find_nearest_fde(EH_FrameHdr header, EH_PtrCtx *ptr_ctx, U64 pc)
{
U64 fde_addr = max_U64;
U64 fde_idx = max_U64;
if (header.version == 1) {
if (header.fde_count > 0) {
U64 first = 0;
U64 first_size = eh_parse_ptr(header.table, 0, ptr_ctx->pc_vaddr, ptr_ctx, header.table_enc, &first);
AssertAlways(first_size);
if (first == pc) {
fde_idx = 0;
goto exit;
}
if (first > pc) {
goto exit;
}
U64 last_off = header.table.size - header.entry_byte_size;
U64 last = 0;
U64 last_size = eh_parse_ptr(header.table, last_off, ptr_ctx->pc_vaddr + last_off, ptr_ctx, header.table_enc, &last);
AssertAlways(last_size);
if (last <= pc) {
fde_idx = header.fde_count - 1;
goto exit;
}
if (first <= pc && pc < last) {
U64 l = 0;
U64 r = header.fde_count - 1;
while (l <= r) {
U64 m = l + (r - l) / 2;
U64 m_pc_off = m * header.entry_byte_size;
U64 m_pc = 0;
U64 m_pc_size = eh_parse_ptr(header.table, m_pc_off, ptr_ctx->pc_vaddr + m_pc_off, ptr_ctx, header.table_enc, &m_pc);
Assert(m_pc_size);
if (m_pc == pc) {
fde_idx = m;
goto exit;
} else if (m_pc < pc) {
l = m + 1;
} else {
r = m - 1;
}
}
fde_idx = l;
}
}
}
exit:;
if (fde_idx < header.fde_count) {
U64 fde_addr_off = (fde_idx * header.entry_byte_size) + header.field_byte_size;
U64 fde_addr_size = eh_parse_ptr(header.table, fde_addr_off, ptr_ctx->pc_vaddr + fde_addr_off, ptr_ctx, header.table_enc, &fde_addr);
Assert(fde_addr_size);
}
return fde_addr;
}
internal int
eh_frame_hdr_entry_sort(void *raw_a, void *raw_b)
{
return ((EH_FrameHdrEntry *)raw_a)->addr < ((EH_FrameHdrEntry *)raw_b)->addr;
}
internal String8
eh_frame_hdr_from_call_frame_info(Arena *arena, U64 fde_count, U64 *fde_offsets, DW_FDE *fde)
{
Temp scratch = scratch_begin(&arena, 1);
// make .eh_frame_hdr
String8List srl = {0};
str8_serial_begin(scratch.arena, &srl);
str8_serial_push_u8(scratch.arena, &srl, 1); // version
str8_serial_push_u8(scratch.arena, &srl, EH_PtrEnc_Omit); // omit eh_frame_ptr field
str8_serial_push_u8(scratch.arena, &srl, EH_PtrEnc_UData8); // fde_count encoding
str8_serial_push_u8(scratch.arena, &srl, EH_PtrEnc_UData8); // table encoding
str8_serial_push_u64(scratch.arena, &srl, fde_count); // fde_count
String8 header = str8_serial_end(scratch.arena, &srl);
// alloc buffer for output
U64 buffer_size = header.size + sizeof(EH_FrameHdrEntry) * fde_count;
U8 *buffer = push_array(arena, U8, buffer_size);
// copy header
MemoryCopyStr8(buffer, header);
// write the table
EH_FrameHdrEntry *table = (EH_FrameHdrEntry *)(buffer + header.size);
for EachIndex(fde_idx, fde_count) {
table[fde_idx].addr = fde[fde_idx].pc_range.min;
table[fde_idx].fde_offset = fde_offsets[fde_idx];
}
radsort(table, fde_count, eh_frame_hdr_entry_sort);
String8 eh_frame_hdr = str8(buffer, buffer_size);
scratch_end(scratch);
return eh_frame_hdr;
}
internal
DW_DECODE_PTR(eh_decode_ptr)
{
EH_DecodePtrCtx *ctx = ud;
return eh_parse_ptr(data, 0, ctx->ptr_ctx->pc_vaddr, ctx->ptr_ctx, ctx->addr_enc, ptr_out);
}
internal String8
eh_string_from_ptr_enc_type(EH_PtrEnc type)
{
switch (type) {
case EH_PtrEnc_Ptr: return str8_lit("Ptr");
case EH_PtrEnc_ULEB128: return str8_lit("ULEB128");
case EH_PtrEnc_UData2: return str8_lit("UData2");
case EH_PtrEnc_UData4: return str8_lit("UData4");
case EH_PtrEnc_UData8: return str8_lit("UData8");
case EH_PtrEnc_Signed: return str8_lit("Signed");
case EH_PtrEnc_SLEB128: return str8_lit("SLEB128");
case EH_PtrEnc_SData2: return str8_lit("SData2");
case EH_PtrEnc_SData4: return str8_lit("SData4");
case EH_PtrEnc_SData8: return str8_lit("SData8");
}
return str8_zero();
}
internal String8
eh_string_from_ptr_enc_modifier(EH_PtrEnc modifier)
{
switch (modifier) {
case EH_PtrEnc_PcRel: return str8_lit("PcRel");
case EH_PtrEnc_TextRel: return str8_lit("TextRel");
case EH_PtrEnc_DataRel: return str8_lit("DataRel");
case EH_PtrEnc_FuncRel: return str8_lit("FuncRel");
case EH_PtrEnc_Aligned: return str8_lit("Aligned");
}
return str8_zero();
}
internal String8
eh_string_from_ptr_enc(Arena *arena, EH_PtrEnc enc)
{
String8 type_str = eh_string_from_ptr_enc_type(enc & EH_PtrEnc_TypeMask);
String8 modifer_str = eh_string_from_ptr_enc_modifier(enc & EH_PtrEnc_ModifierMask);
String8 indir_str = enc & EH_PtrEnc_Indirect ? str8_lit("Indirect") : str8_zero();
String8 result = str8f(arena, "Type: %S, Modifier %S (%S)", type_str, modifer_str, indir_str);
return result;
}
+124
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@@ -0,0 +1,124 @@
// Copyright (c) Epic Games Tools
// Licensed under the MIT license (https://opensource.org/license/mit/)
#ifndef EH_FRAME_H
#define EH_FRAME_H
////////////////////////////////
//~ Format
typedef U8 EH_PtrEnc;
enum
{
EH_PtrEnc_Ptr = 0x00, // Pointer sized unsigned value
EH_PtrEnc_ULEB128 = 0x01, // Unsigned LE base-128 value
EH_PtrEnc_UData2 = 0x02, // Unsigned 16-bit value
EH_PtrEnc_UData4 = 0x03, // Unsigned 32-bit value
EH_PtrEnc_UData8 = 0x04, // Unsigned 64-bit value
EH_PtrEnc_Signed = 0x08, // Signed pointer
EH_PtrEnc_SLEB128 = 0x09, // Signed LE base-128 value
EH_PtrEnc_SData2 = 0x0A, // Signed 16-bit value
EH_PtrEnc_SData4 = 0x0B, // Signed 32-bit value
EH_PtrEnc_SData8 = 0x0C, // Signed 64-bit value
EH_PtrEnc_TypeMask = 0x0F,
};
enum
{
EH_PtrEnc_PcRel = 0x10, // Value is relative to the current program counter.
EH_PtrEnc_TextRel = 0x20, // Value is relative to the .text section.
EH_PtrEnc_DataRel = 0x30, // Value is relative to the .got or .eh_frame_hdr section.
EH_PtrEnc_FuncRel = 0x40, // Value is relative to the function.
EH_PtrEnc_Aligned = 0x50, // Value is aligned to an address unit sized boundary.
EH_PtrEnc_ModifierMask = 0x70,
};
enum
{
EH_PtrEnc_Indirect = 0x80, // Value is stored in virtual memory.
EH_PtrEnc_Omit = 0xFF,
};
typedef struct EH_PtrCtx
{
U64 pc_vaddr; // address where pointer is being read
U64 text_vaddr; // base address of section with instructions (used for encoding pointer on SH and IA64)
U64 data_vaddr; // base address of data section (used for encoding pointer on x86-64)
U64 func_vaddr; // base address of function where IP is located
U64 ptr_align;
} EH_PtrCtx;
typedef U8 EH_AugFlags;
enum
{
EH_AugFlag_HasLSDA = (1 << 0),
EH_AugFlag_HasHandler = (1 << 1),
EH_AugFlag_HasAddrEnc = (1 << 2),
};
typedef struct EH_Augmentation
{
EH_AugFlags flags;
U64 handler_ip;
EH_PtrEnc handler_encoding;
EH_PtrEnc lsda_encoding;
EH_PtrEnc addr_encoding;
} EH_Augmentation;
////////////////////////////////
//~ Parser
enum
{
EH_CIE_Ext_AddrEnc,
EH_CIE_Ext_LSDAEnc,
EH_CIE_Ext_HandlerEnc,
EH_CIE_Ext_HandlerIp,
} EH_CIE_Ext;
typedef struct EH_FrameHdrEntry
{
U64 addr;
U64 fde_offset;
} EH_FrameHdrEntry;
typedef struct EH_FrameHdr
{
U8 version;
EH_PtrEnc eh_frame_ptr_enc;
EH_PtrEnc fde_count_enc;
EH_PtrEnc table_enc;
U64 field_byte_size;
U64 entry_byte_size;
U64 fde_count;
U64 eh_frame_ptr;
String8 table;
} EH_FrameHdr;
typedef struct EH_DecodePtrCtx
{
EH_PtrEnc addr_enc;
EH_PtrCtx *ptr_ctx;
} EH_DecodePtrCtx;
////////////////////////////////
internal U64 eh_parse_ptr(String8 frame_base, U64 off, U64 pc, EH_PtrCtx *ptr_ctx, EH_PtrEnc encoding, U64 *ptr_out);
internal EH_FrameHdr eh_parse_frame_hdr(String8 data, U64 address_size, EH_PtrCtx *ptr_ctx);
internal U64 eh_parse_aug_data(String8 aug_string, String8 aug_data, U64 pc, EH_PtrCtx *ptr_ctx, EH_Augmentation *aug_out);
internal B32 eh_parse_cie(String8 data, DW_Format format, Arch arch, U64 pc, EH_PtrCtx *ptr_ctx, DW_CIE *cie_out);
internal B32 eh_parse_fde(String8 data, DW_Format format, U64 pc, DW_CIE *cie, EH_PtrCtx *ptr_ctx, DW_FDE *fde_out);
internal U64 eh_find_nearest_fde(EH_FrameHdr header, EH_PtrCtx *ptr_ctx, U64 pc);
internal String8 eh_frame_hdr_from_call_frame_info(Arena *arena, U64 fde_count, U64 *fde_offsets, struct DW_FDE *fde);
////////////////////////////////
//~ Enum -> String
internal String8 eh_string_from_ptr_enc_type(EH_PtrEnc type);
internal String8 eh_string_from_ptr_enc_modifier(EH_PtrEnc modifier);
internal String8 eh_string_from_ptr_enc(Arena *arena, EH_PtrEnc enc);
#endif // EH_FRAME_H