Runtime: Refactor platform-dependent image inspection code.

stdlib/public/runtime/CMakeLists.txt

@@ -40,6 +40,9 @@ set(swift_runtime_sources
     ErrorDefaultImpls.cpp
     Heap.cpp
     HeapObject.cpp
+    ImageInspectionMachO.cpp
+    ImageInspectionELF.cpp
+    ImageInspectionWin32.cpp
     KnownMetadata.cpp
     Metadata.cpp
     MetadataLookup.cpp

stdlib/public/runtime/CygwinPort.cpp

@@ -32,112 +32,6 @@ using namespace swift;
 
 static std::mutex swiftOnceMutex;
 
-int swift::_swift_dl_iterate_phdr(int (*Callback)(struct dl_phdr_info *info,
-                                                  size_t size, void *data),
-                                  void *data) {
-  DWORD procId = GetCurrentProcessId();
-  HANDLE procHandle =
-      OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, FALSE, procId);
-  if (!procHandle) {
-    swift::fatalError(/* flags = */ 0, "OpenProcess() failed");
-    return 0;
-  }
-
-  int lastRet = 0;
-
-  std::vector<HMODULE> modules(1024);
-  DWORD neededSize;
-
-  BOOL ret = EnumProcessModules(procHandle, modules.data(),
-                                modules.size() * sizeof(HMODULE), &neededSize);
-
-  if (!ret) {
-    swift::fatalError(/* flags = */ 0, "EnumProcessModules() failed");
-    return 0;
-  }
-
-  if (modules.size() * sizeof(HMODULE) < neededSize) {
-    modules.resize(neededSize / sizeof(HMODULE));
-    ret = EnumProcessModules(procHandle, modules.data(),
-                             modules.size() * sizeof(HMODULE), &neededSize);
-  }
-
-  if (!ret) {
-    swift::fatalError(/* flags = */ 0, "EnumProcessModules() failed");
-    return 0;
-  }
-
-  for (unsigned i = 0; i < neededSize / sizeof(HMODULE); i++) {
-    char modName[MAX_PATH];
-
-    if (!GetModuleFileNameExA(procHandle, modules[i], modName,
-                              sizeof(modName))) {
-      swift::fatalError(/* flags = */ 0, "GetModuleFileNameExA() failed");
-    }
-
-    dl_phdr_info hdr;
-    hdr.dlpi_name = modName;
-    hdr.dlpi_addr = modules[i];
-
-    lastRet = Callback(&hdr, sizeof(hdr), data);
-    if (lastRet != 0)
-      break;
-  }
-
-  CloseHandle(procHandle);
-
-  return lastRet;
-}
-
-uint8_t *swift::_swift_getSectionDataPE(void *handle, const char *sectionName,
-                                        unsigned long *sectionSize) {
-  // In Cygwin, dlopen() returns PE/COFF image pointer.
-  // This is relying on undocumented feature of Windows API LoadLibrary().
-  unsigned char *peStart = (unsigned char *)handle;
-
-  const int kLocationOfNtHeaderOffset = 0x3C;
-  int ntHeadersOffset =
-      *reinterpret_cast<int32_t *>(peStart + kLocationOfNtHeaderOffset);
-
-  bool assert1 =
-      peStart[ntHeadersOffset] == 'P' && peStart[ntHeadersOffset + 1] == 'E';
-  if (!assert1) {
-    swift::fatalError(/* flags = */ 0, "_swift_getSectionDataPE()'s finding PE failed");
-  }
-
-  unsigned char *coff = peStart + ntHeadersOffset + 4;
-
-  int16_t numberOfSections = *(int16_t *)(coff + 2);
-
-  // SizeOfOptionalHeader
-  int16_t sizeOfOptionalHeader = *(int16_t *)(coff + 16);
-
-  const int kCoffFileHeaderSize = 20;
-  unsigned char *sectionTableBase =
-      coff + kCoffFileHeaderSize + sizeOfOptionalHeader;
-
-  // Section Header Record
-  const int kSectionRecordSize = 40;
-
-  unsigned char *sectionHeader = sectionTableBase;
-  for (int i = 0; i < numberOfSections; i++) {
-    uint32_t virtualSize = *(uint32_t *)&sectionHeader[8];
-    uint32_t virtualAddress = *(uint32_t *)&sectionHeader[12];
-
-    char nameOfThisSection[9];
-    memcpy(nameOfThisSection, sectionHeader, 8);
-    nameOfThisSection[8] = '\0';
-
-    if (strcmp(sectionName, nameOfThisSection) == 0) {
-      *sectionSize = virtualSize;
-      return (uint8_t *)handle + virtualAddress;
-    }
-    sectionHeader += kSectionRecordSize;
-  }
-
-  return nullptr;
-}
-
 #if !defined(_MSC_VER)
 void swift::_swift_once_f(uintptr_t *predicate, void *context,
                           void (*function)(void *)) {

stdlib/public/runtime/ImageInspection.h

@@ -0,0 +1,42 @@
+//===--- ImageInspection.h - Image inspection routines --------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This file includes routines that extract metadata from executable and
+// dynamic library image files generated by the Swift compiler. The
+// concrete implementations vary greatly by platform.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_RUNTIME_IMAGE_INSPECTION_H
+#define SWIFT_RUNTIME_IMAGE_INSPECTION_H
+
+#include <cstdint>
+
+namespace swift {
+
+/// Load the metadata from the image necessary to find a type's
+/// protocol conformance.
+void initializeProtocolConformanceLookup();
+
+/// Load the metadata from the image necessary to find a type by name.
+void initializeTypeMetadataRecordLookup();
+
+// Callbacks to register metadata from an image to the runtime.
+
+void addImageProtocolConformanceBlockCallback(const void *start,
+                                              uintptr_t size);
+void addImageTypeMetadataRecordBlockCallback(const void *start,
+                                             uintptr_t size);
+
+} // end namespace swift
+
+#endif // SWIFT_RUNTIME_IMAGE_INSPECTION_H

stdlib/public/runtime/ImageInspectionELF.cpp

@@ -0,0 +1,101 @@
+//===--- ImageInspectionELFDynamic.cpp - ELF image inspection -------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This file includes routines that interact with ld*.so on ELF-based platforms
+// to extract runtime metadata embedded in dynamically linked ELF images
+// generated by the Swift compiler.
+//
+//===----------------------------------------------------------------------===//
+
+#if defined(__ELF__) || defined(__ANDROID__)
+
+#include "ImageInspection.h"
+#include <elf.h>
+#include <link.h>
+#include <dlfcn.h>
+#include <string.h>
+
+using namespace swift;
+
+/// The symbol name in the image that identifies the beginning of the
+/// protocol conformances table.
+static const char ProtocolConformancesSymbol[] =
+  ".swift2_protocol_conformances_start";
+/// The symbol name in the image that identifies the beginning of the
+/// type metadata record table.
+static const char TypeMetadataRecordsSymbol[] =
+  ".swift2_type_metadata_start";
+
+/// Context arguments passed down from dl_iterate_phdr to its callback.
+struct InspectArgs {
+  /// Symbol name to look up.
+  const char *symbolName;
+  /// Callback function to invoke with the metadata block.
+  void (*addBlock)(const void *start, uintptr_t size);
+};
+
+static int iteratePHDRCallback(struct dl_phdr_info *info,
+                               size_t size, void *data) {
+  const InspectArgs *inspectArgs = reinterpret_cast<const InspectArgs *>(data);
+  void *handle;
+  if (!info->dlpi_name || info->dlpi_name[0] == '\0') {
+    handle = dlopen(nullptr, RTLD_LAZY);
+  } else {
+    handle = dlopen(info->dlpi_name, RTLD_LAZY | RTLD_NOLOAD);
+  }
+
+  if (!handle) {
+    // Not a shared library.
+    return 0;
+  }
+
+  const char *conformances =
+    reinterpret_cast<const char*>(dlsym(handle, inspectArgs->symbolName));
+
+  if (!conformances) {
+    // if there are no conformances, don't hold this handle open.
+    dlclose(handle);
+    return 0;
+  }
+
+  // Extract the size of the conformances block from the head of the section.
+  uint64_t conformancesSize;
+  memcpy(&conformancesSize, conformances, sizeof(conformancesSize));
+  conformances += sizeof(conformancesSize);
+
+  inspectArgs->addBlock(conformances, conformancesSize);
+
+  dlclose(handle);
+  return 0;
+}
+
+void swift::initializeProtocolConformanceLookup() {
+  // Search the loaded dls. This only searches the already
+  // loaded ones.
+  // FIXME: Find a way to have this continue to happen for dlopen-ed images.
+  // rdar://problem/19045112
+  InspectArgs ProtocolConformanceArgs = {
+    ProtocolConformancesSymbol,
+    addImageProtocolConformanceBlockCallback
+  };
+  dl_iterate_phdr(iteratePHDRCallback, &ProtocolConformanceArgs);
+}
+
+void swift::initializeTypeMetadataRecordLookup() {
+  InspectArgs TypeMetadataRecordArgs = {
+    TypeMetadataRecordsSymbol,
+    addImageTypeMetadataRecordBlockCallback
+  };
+  dl_iterate_phdr(iteratePHDRCallback, &TypeMetadataRecordArgs);
+}
+
+#endif // defined(__ELF__) || defined(__ANDROID__)

stdlib/public/runtime/ImageInspectionMachO.cpp

@@ -0,0 +1,73 @@
+//===--- ImageInspectionMachO.cpp - Mach-O image inspection ---------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// 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__)
+
+#include "ImageInspection.h"
+#include <mach-o/dyld.h>
+#include <mach-o/getsect.h>
+#include <assert.h>
+
+using namespace swift;
+
+namespace {
+/// The Mach-O section name for the section containing protocol conformances.
+/// This lives within SEG_TEXT.
+constexpr const char ProtocolConformancesSection[] = "__swift2_proto";
+/// The Mach-O section name for the section containing type references.
+/// This lives within SEG_TEXT.
+constexpr const char TypeMetadataRecordSection[] = "__swift2_types";
+
+template<const char *SECTION_NAME,
+         void CONSUME_BLOCK(const void *start, uintptr_t size)>
+void addImageCallback(const mach_header *mh, intptr_t vmaddr_slide) {
+#ifdef __LP64__
+  using mach_header_platform = mach_header_64;
+  assert(mh->magic == MH_MAGIC_64 && "loaded non-64-bit image?!");
+#else
+  using mach_header_platform = mach_header;
+#endif
+
+  // Look for a __swift2_proto section.
+  unsigned long size;
+  const uint8_t *section =
+  getsectiondata(reinterpret_cast<const mach_header_platform *>(mh),
+                 SEG_TEXT, SECTION_NAME,
+                 &size);
+
+  if (!section)
+    return;
+
+  CONSUME_BLOCK(section, size);
+}
+
+} // end anonymous namespace
+
+void swift::initializeProtocolConformanceLookup() {
+  _dyld_register_func_for_add_image(
+    addImageCallback<ProtocolConformancesSection,
+                     addImageProtocolConformanceBlockCallback>);
+}
+void swift::initializeTypeMetadataRecordLookup() {
+  _dyld_register_func_for_add_image(
+    addImageCallback<TypeMetadataRecordSection,
+                     addImageTypeMetadataRecordBlockCallback>);
+
+}
+
+#endif // defined(__APPLE__) && defined(__MACH__)