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Unified Diff: courgette/rel32_finder_win32_x86.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/rel32_finder_win32_x86.cc
diff --git a/courgette/rel32_finder_win32_x86.cc b/courgette/rel32_finder_win32_x86.cc
deleted file mode 100644
index 61ff9696d5ac19174d514c8930111e64c326342e..0000000000000000000000000000000000000000
--- a/courgette/rel32_finder_win32_x86.cc
+++ /dev/null
@@ -1,113 +0,0 @@
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include <stdint.h>
-
-#include "courgette/rel32_finder_win32_x86.h"
-
-namespace courgette {
-
-Rel32FinderWin32X86::Rel32FinderWin32X86(RVA relocs_start_rva,
- RVA relocs_end_rva)
- : relocs_start_rva_(relocs_start_rva), relocs_end_rva_(relocs_end_rva) {
-}
-
-Rel32FinderWin32X86::~Rel32FinderWin32X86() {
-}
-
-void Rel32FinderWin32X86::SwapRel32Locations(std::vector<RVA>* dest) {
- dest->swap(rel32_locations_);
-}
-
-#if COURGETTE_HISTOGRAM_TARGETS
-void Rel32FinderWin32X86::SwapRel32TargetRVAs(std::map<RVA, int>* dest) {
- dest->swap(rel32_target_rvas_);
-}
-#endif
-
-Rel32FinderWin32X86_Basic::Rel32FinderWin32X86_Basic(RVA relocs_start_rva,
- RVA relocs_end_rva)
- : Rel32FinderWin32X86(relocs_start_rva, relocs_end_rva) {
-}
-
-Rel32FinderWin32X86_Basic::~Rel32FinderWin32X86_Basic() {
-}
-
-void Rel32FinderWin32X86_Basic::Find(const uint8_t* start_pointer,
- const uint8_t* end_pointer,
- RVA start_rva,
- RVA end_rva,
- const std::vector<RVA>& abs32_locations) {
- // 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>::const_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);
-
- // Skip the base reloation table if we encounter it.
- // Note: We're not bothering to handle the edge case where a Rel32 pointer
- // collides with |relocs_start_rva_| by being {1, 2, 3}-bytes before it.
- if (current_rva == relocs_start_rva_) {
- if (relocs_start_rva_ < relocs_end_rva_) {
- p += relocs_end_rva_ - relocs_start_rva_;
- 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;
-
- 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;
- }
- }
- 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);
- // Valid, rel32 target must be within image, and within this section.
- // Subsumes |target_rva| != |kUnassignedRVA|.
- if (start_rva <= target_rva && target_rva < end_rva) {
- rel32_locations_.push_back(rel32_rva);
-#if COURGETTE_HISTOGRAM_TARGETS
- ++rel32_target_rvas_[target_rva];
-#endif
- p = rel32 + 4;
- continue;
- }
- }
- p += 1;
- }
-}
-
-} // namespace courgette

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