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swift-mirror/stdlib/public/runtime/ImageInspectionMachO.cpp

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//===--- ImageInspectionMachO.cpp - Mach-O image inspection ---------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
///
/// \file
///
/// This file includes routines that interact with dyld on Mach-O-based
/// platforms to extract runtime metadata embedded in images generated by the
/// Swift compiler.
///
//===----------------------------------------------------------------------===//
#if defined(__APPLE__) && defined(__MACH__) && \
!defined(SWIFT_RUNTIME_STATIC_IMAGE_INSPECTION)
#include "ImageInspection.h"
#include "ImageInspectionCommon.h"
#include "swift/Runtime/Config.h"
#include <mach-o/dyld.h>
#include <mach-o/getsect.h>
#if SWIFT_OBJC_INTEROP
#include <objc/runtime.h>
#endif
#include <assert.h>
#include <dlfcn.h>
#if __has_include(<objc/objc-internal.h>) && __has_include(<mach-o/dyld_priv.h>)
#include <mach-o/dyld_priv.h>
#include <objc/objc-internal.h>
#else
// Bring our own definition of enum _dyld_section_location_kind and some of its
// values. They'll be unused when we can't include dyld_priv.h, but the code
// needs them in order to compile.
enum _dyld_section_location_kind {
_dyld_section_location_text_swift5_protos,
_dyld_section_location_text_swift5_proto,
_dyld_section_location_text_swift5_types,
_dyld_section_location_text_swift5_replace,
_dyld_section_location_text_swift5_replace2,
_dyld_section_location_text_swift5_ac_funcs,
_dyld_section_location_text_swift5_ac_p_funcs,
};
#endif
// Bring our own definition of _dyld_section_location constants in case we're
// using an older SDK that doesn't have them.
#define _dyld_section_location_text_swift5_protos 0
#define _dyld_section_location_text_swift5_proto 1
#define _dyld_section_location_text_swift5_types 2
#define _dyld_section_location_text_swift5_replace 3
#define _dyld_section_location_text_swift5_replace2 4
#define _dyld_section_location_text_swift5_ac_funcs 5
#define _dyld_section_location_text_swift5_ac_p_funcs 6
#if OBJC_ADDLOADIMAGEFUNC2_DEFINED
// Redefine _dyld_lookup_section_info as weak so we can build against it but
// still run when it's not present at runtime. Note that we don't have to check
// for its presence at runtime, as it's guaranteed to be available if we get
// the callbacks from objc_addLoadImageFunc2.
LLVM_ATTRIBUTE_WEAK
struct _dyld_section_info_result
_dyld_lookup_section_info(const struct mach_header *mh,
_dyld_section_location_info_t locationHandle,
enum _dyld_section_location_kind kind);
#else
// If we don't have objc_addLoadImageFunc2, fall back to objc_addLoadImageFunc.
// Use a #define so we don't have to conditionalize the calling code below.
#define objc_addLoadImageFunc2 objc_addLoadImageFunc
#endif
using namespace swift;
namespace {
constexpr const char ProtocolsSection[] = MachOProtocolsSection;
constexpr const char ProtocolConformancesSection[] =
MachOProtocolConformancesSection;
constexpr const char TypeMetadataRecordSection[] =
MachOTypeMetadataRecordSection;
constexpr const char DynamicReplacementSection[] =
MachODynamicReplacementSection;
constexpr const char DynamicReplacementSomeSection[] =
MachODynamicReplacementSomeSection;
constexpr const char AccessibleFunctionsSection[] =
MachOAccessibleFunctionsSection;
constexpr const char TextSegment[] = MachOTextSegment;
#if __POINTER_WIDTH__ == 64
using mach_header_platform = mach_header_64;
#else
using mach_header_platform = mach_header;
#endif
// Callback for objc_addLoadImageFunc that just takes a mach_header.
template <const char *SEGMENT_NAME, const char *SECTION_NAME, int SECTION_KIND,
void CONSUME_BLOCK(const void *baseAddress, const void *start,
uintptr_t size)>
void addImageCallback(const mach_header *mh) {
#if __POINTER_WIDTH__ == 64
assert(mh->magic == MH_MAGIC_64 && "loaded non-64-bit image?!");
#endif
unsigned long size;
const uint8_t *section =
getsectiondata(reinterpret_cast<const mach_header_platform *>(mh),
SEGMENT_NAME, SECTION_NAME,
&size);
if (!section)
return;
CONSUME_BLOCK(mh, section, size);
}
// Callback for objc_addLoadImageFunc2 that takes a mach_header and dyld info.
#if OBJC_ADDLOADIMAGEFUNC2_DEFINED
template <const char *SEGMENT_NAME, const char *SECTION_NAME, int SECTION_KIND,
void CONSUME_BLOCK(const void *baseAddress, const void *start,
uintptr_t size)>
void addImageCallback(const mach_header *mh,
struct _dyld_section_location_info_s *dyldInfo) {
#if __POINTER_WIDTH__ == 64
assert(mh->magic == MH_MAGIC_64 && "loaded non-64-bit image?!");
#endif
auto result = _dyld_lookup_section_info(
mh, dyldInfo,
static_cast<enum _dyld_section_location_kind>(SECTION_KIND));
if (result.buffer)
CONSUME_BLOCK(mh, result.buffer, result.bufferSize);
}
#endif
// Callback for _dyld_register_func_for_add_image that takes a mach_header and a
// slide.
template <const char *SEGMENT_NAME, const char *SECTION_NAME, int SECTION_KIND,
void CONSUME_BLOCK(const void *baseAddress, const void *start,
uintptr_t size)>
void addImageCallback(const mach_header *mh, intptr_t vmaddr_slide) {
addImageCallback<SEGMENT_NAME, SECTION_NAME, SECTION_KIND, CONSUME_BLOCK>(mh);
}
// Callback for objc_addLoadImageFunc that just takes a mach_header.
template <const char *SEGMENT_NAME, const char *SECTION_NAME,
const char *SEGMENT_NAME2, const char *SECTION_NAME2,
int SECTION_KIND, int SECTION_KIND2,
void CONSUME_BLOCK(const void *baseAddress, const void *start,
uintptr_t size, const void *start2,
uintptr_t size2)>
void addImageCallback2Sections(const mach_header *mh) {
#if __POINTER_WIDTH__ == 64
assert(mh->magic == MH_MAGIC_64 && "loaded non-64-bit image?!");
#endif
// Look for a section.
unsigned long size;
const uint8_t *section =
getsectiondata(reinterpret_cast<const mach_header_platform *>(mh),
SEGMENT_NAME, SECTION_NAME,
&size);
if (!section)
return;
// Look for another section.
unsigned long size2;
const uint8_t *section2 =
getsectiondata(reinterpret_cast<const mach_header_platform *>(mh),
SEGMENT_NAME2, SECTION_NAME2,
&size2);
if (!section2)
size2 = 0;
CONSUME_BLOCK(mh, section, size, section2, size2);
}
// Callback for objc_addLoadImageFunc2 that takes a mach_header and dyld info.
#if OBJC_ADDLOADIMAGEFUNC2_DEFINED
template <const char *SEGMENT_NAME, const char *SECTION_NAME,
const char *SEGMENT_NAME2, const char *SECTION_NAME2,
int SECTION_KIND, int SECTION_KIND2,
void CONSUME_BLOCK(const void *baseAddress, const void *start,
uintptr_t size, const void *start2,
uintptr_t size2)>
void addImageCallback2Sections(const mach_header *mh,
struct _dyld_section_location_info_s *dyldInfo) {
#if __POINTER_WIDTH__ == 64
assert(mh->magic == MH_MAGIC_64 && "loaded non-64-bit image?!");
#endif
// Look for a section.
auto result = _dyld_lookup_section_info(
mh, dyldInfo,
static_cast<enum _dyld_section_location_kind>(SECTION_KIND));
if (!result.buffer)
return;
auto result2 = _dyld_lookup_section_info(
mh, dyldInfo,
static_cast<enum _dyld_section_location_kind>(SECTION_KIND2));
// No NULL check here, we allow this one not to be present. dyld gives us
// a NULL pointer and 0 size when the section isn't in the dylib so we don't
// need to zero anything out.
CONSUME_BLOCK(mh, result.buffer, result.bufferSize, result2.buffer,
result2.bufferSize);
}
#endif
// Callback for _dyld_register_func_for_add_image that takes a mach_header and a
// slide.
template <const char *SEGMENT_NAME, const char *SECTION_NAME,
const char *SEGMENT_NAME2, const char *SECTION_NAME2,
int SECTION_KIND, int SECTION_KIND2,
void CONSUME_BLOCK(const void *baseAddress, const void *start,
uintptr_t size, const void *start2,
uintptr_t size2)>
void addImageCallback2Sections(const mach_header *mh, intptr_t vmaddr_slide) {
addImageCallback2Sections<SEGMENT_NAME, SECTION_NAME, SEGMENT_NAME2,
SECTION_NAME2, SECTION_KIND, SECTION_KIND2,
CONSUME_BLOCK>(mh);
}
} // end anonymous namespace
#if OBJC_ADDLOADIMAGEFUNC_DEFINED && SWIFT_OBJC_INTEROP
#define REGISTER_FUNC(...) \
if (SWIFT_RUNTIME_WEAK_CHECK(objc_addLoadImageFunc2)) { \
SWIFT_RUNTIME_WEAK_USE(objc_addLoadImageFunc2(__VA_ARGS__)); \
} else if (__builtin_available(macOS 10.15, iOS 13, tvOS 13, \
watchOS 6, *)) { \
objc_addLoadImageFunc(__VA_ARGS__); \
} else { \
_dyld_register_func_for_add_image(__VA_ARGS__); \
}
#else
#define REGISTER_FUNC(...) _dyld_register_func_for_add_image(__VA_ARGS__)
#endif
// WARNING: the callbacks are called from unsafe contexts (with the dyld and
// ObjC runtime locks held) and must be very careful in what they do. Locking
// must be arranged to avoid deadlocks (other code must never call out to dyld
// or ObjC holding a lock that gets taken in one of these callbacks) and the
// new/delete operators must not be called, in case a program supplies an
// overload which does not cooperate with these requirements.
void swift::initializeProtocolLookup() {
REGISTER_FUNC(addImageCallback<TextSegment, ProtocolsSection,
_dyld_section_location_text_swift5_protos,
addImageProtocolsBlockCallbackUnsafe>);
}
void swift::initializeProtocolConformanceLookup() {
REGISTER_FUNC(
addImageCallback<TextSegment, ProtocolConformancesSection,
_dyld_section_location_text_swift5_proto,
addImageProtocolConformanceBlockCallbackUnsafe>);
}
void swift::initializeTypeMetadataRecordLookup() {
REGISTER_FUNC(
addImageCallback<TextSegment, TypeMetadataRecordSection,
_dyld_section_location_text_swift5_types,
addImageTypeMetadataRecordBlockCallbackUnsafe>);
}
void swift::initializeDynamicReplacementLookup() {
REGISTER_FUNC(
addImageCallback2Sections<TextSegment, DynamicReplacementSection,
TextSegment, DynamicReplacementSomeSection,
_dyld_section_location_text_swift5_replace,
_dyld_section_location_text_swift5_replace2,
addImageDynamicReplacementBlockCallback>);
}
void swift::initializeAccessibleFunctionsLookup() {
REGISTER_FUNC(
addImageCallback<TextSegment, AccessibleFunctionsSection,
_dyld_section_location_text_swift5_ac_funcs,
addImageAccessibleFunctionsBlockCallbackUnsafe>);
}
#endif // defined(__APPLE__) && defined(__MACH__) &&
// !defined(SWIFT_RUNTIME_STATIC_IMAGE_INSPECTION)