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Unified Diff: courgette/disassembler_win32_x64.cc

Issue 2008253004: Refactor rel32 searching process for x64 to make it more similar to x86. (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: Improve rel32_finder doc Created 4 years, 7 months ago
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Index: courgette/disassembler_win32_x64.cc
diff --git a/courgette/disassembler_win32_x64.cc b/courgette/disassembler_win32_x64.cc
index c4d89e452e62875fe402af773f60110710691236..d4ed28cd24b8080c311214ab5cffebe7c16365bf 100644
--- a/courgette/disassembler_win32_x64.cc
+++ b/courgette/disassembler_win32_x64.cc
@@ -10,6 +10,7 @@
#include "base/numerics/safe_conversions.h"
#include "courgette/assembly_program.h"
#include "courgette/courgette.h"
+#include "courgette/rel32_finder_x64.h"
#if COURGETTE_HISTOGRAM_TARGETS
#include <iostream>
@@ -43,7 +44,6 @@ void DisassemblerWin32X64::ParseRel32RelocsFromSection(const Section* section) {
FileOffset start_file_offset = section->file_offset_of_raw_data;
FileOffset end_file_offset = start_file_offset + section->size_of_raw_data;
- RVA relocs_start_rva = base_relocation_table().address_;
const uint8_t* start_pointer = FileOffsetToPointer(start_file_offset);
const uint8_t* end_pointer = FileOffsetToPointer(end_file_offset);
@@ -51,92 +51,17 @@ void DisassemblerWin32X64::ParseRel32RelocsFromSection(const Section* section) {
RVA start_rva = FileOffsetToRVA(start_file_offset);
RVA end_rva = start_rva + section->virtual_size;
- // Quick way to convert from Pointer to RVA within a single Section is to
- // subtract |pointer_to_rva|.
- const uint8_t* const adjust_pointer_to_rva = start_pointer - start_rva;
-
- std::vector<RVA>::iterator abs32_pos = abs32_locations_.begin();
-
- // Find the rel32 relocations.
- const uint8_t* p = start_pointer;
- while (p < end_pointer) {
- RVA current_rva = static_cast<RVA>(p - adjust_pointer_to_rva);
- if (current_rva == relocs_start_rva) {
- uint32_t relocs_size = base_relocation_table().size_;
- if (relocs_size) {
- p += relocs_size;
- continue;
- }
- }
-
- // Heuristic discovery of rel32 locations in instruction stream: are the
- // next few bytes the start of an instruction containing a rel32
- // addressing mode?
- const uint8_t* rel32 = nullptr;
- bool is_rip_relative = false;
-
- if (p + 5 <= end_pointer) {
- if (*p == 0xE8 || *p == 0xE9) // jmp rel32 and call rel32
- rel32 = p + 1;
- }
- if (p + 6 <= end_pointer) {
- if (*p == 0x0F && (*(p + 1) & 0xF0) == 0x80) { // Jcc long form
- if (p[1] != 0x8A && p[1] != 0x8B) // JPE/JPO unlikely
- rel32 = p + 2;
- } else if (*p == 0xFF && (*(p + 1) == 0x15 || *(p + 1) == 0x25)) {
- // rip relative call/jmp
- rel32 = p + 2;
- is_rip_relative = true;
- }
- }
- if (p + 7 <= end_pointer) {
- if ((*p & 0xFB) == 0x48 && *(p + 1) == 0x8D &&
- (*(p + 2) & 0xC7) == 0x05) {
- // rip relative lea
- rel32 = p + 3;
- is_rip_relative = true;
- } else if ((*p & 0xFB) == 0x48 && *(p + 1) == 0x8B &&
- (*(p + 2) & 0xC7) == 0x05) {
- // rip relative mov
- rel32 = p + 3;
- is_rip_relative = true;
- }
- }
-
- if (rel32) {
- RVA rel32_rva = static_cast<RVA>(rel32 - adjust_pointer_to_rva);
-
- // Is there an abs32 reloc overlapping the candidate?
- while (abs32_pos != abs32_locations_.end() && *abs32_pos < rel32_rva - 3)
- ++abs32_pos;
- // Now: (*abs32_pos > rel32_rva - 4) i.e. the lowest addressed 4-byte
- // region that could overlap rel32_rva.
- if (abs32_pos != abs32_locations_.end()) {
- if (*abs32_pos < rel32_rva + 4) {
- // Beginning of abs32 reloc is before end of rel32 reloc so they
- // overlap. Skip four bytes past the abs32 reloc.
- p += (*abs32_pos + 4) - current_rva;
- continue;
- }
- }
-
- // + 4 since offset is relative to start of next instruction.
- RVA target_rva = rel32_rva + 4 + Read32LittleEndian(rel32);
- // To be valid, rel32 target must be within image, and within this
- // section.
- if (target_rva < size_of_image_ && // Subsumes rva != kUnassignedRVA.
- (is_rip_relative ||
- (start_rva <= target_rva && target_rva < end_rva))) {
- rel32_locations_.push_back(rel32_rva);
+ Rel32FinderX64 finder(
+ base_relocation_table().address_,
+ base_relocation_table().address_ + base_relocation_table().size_,
+ size_of_image_);
+ finder.Find(start_pointer, end_pointer, start_rva, end_rva, abs32_locations_);
+ finder.SwapRel32Locations(&rel32_locations_);
+
#if COURGETTE_HISTOGRAM_TARGETS
- ++rel32_target_rvas_[target_rva];
+ DCHECK(rel32_target_rvas_.empty());
+ finder.SwapRel32TargetRVAs(&rel32_target_rvas_);
#endif
- p = rel32 + 4;
- continue;
- }
- }
- p += 1;
- }
}
} // namespace courgette

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