Merge pull request swiftlang#32493 from augusto2112/elf-shim-metadata-sections

Move 'MetadataSections' from 'ImageInspectionElf.h' to SwiftShims

Author: compnerd

stdlib/public/SwiftShims/CMakeLists.txt

@@ -7,6 +7,7 @@ set(sources
   KeyPath.h
   LibcOverlayShims.h
   LibcShims.h
+  MetadataSections.h
   Random.h
   RefCount.h
   RuntimeShims.h

stdlib/public/SwiftShims/MetadataSections.h

@@ -0,0 +1,63 @@
+//===--- MetadataSections.h -----------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2020 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 contains the declaration of the MetadataSectionsRange and 
+/// MetadataSections struct, which represent, respectively,  information about  
+/// an image's section, and an image's metadata information (which is composed
+/// of multiple section information).
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_STDLIB_SHIMS_METADATASECTIONS_H
+#define SWIFT_STDLIB_SHIMS_METADATASECTIONS_H
+
+#include "SwiftStddef.h"
+#include "SwiftStdint.h"
+
+#ifdef __cplusplus
+namespace swift { 
+extern "C" {
+#endif
+
+typedef struct MetadataSectionRange {
+  __swift_uintptr_t start;
+  __swift_size_t length;
+} MetadataSectionRange;
+
+struct MetadataSections {
+  __swift_uintptr_t version;
+  __swift_uintptr_t reserved;
+
+  struct MetadataSections *next;
+  struct MetadataSections *prev;
+
+
+  MetadataSectionRange swift5_protocols;
+  MetadataSectionRange swift5_protocol_conformances;
+  MetadataSectionRange swift5_type_metadata;
+  MetadataSectionRange swift5_typeref;
+  MetadataSectionRange swift5_reflstr;
+  MetadataSectionRange swift5_fieldmd;
+  MetadataSectionRange swift5_assocty;
+  MetadataSectionRange swift5_replace;
+  MetadataSectionRange swift5_replac2;
+  MetadataSectionRange swift5_builtin;
+  MetadataSectionRange swift5_capture;
+};
+
+#ifdef __cplusplus
+} //extern "C"
+} // namespace swift
+#endif
+
+#endif // SWIFT_STDLIB_SHIMS_METADATASECTIONS_H

stdlib/public/SwiftShims/module.modulemap

@@ -6,6 +6,7 @@ module SwiftShims {
   header "HeapObject.h"
   header "KeyPath.h"
   header "LibcShims.h"
+  header "MetadataSections.h"
   header "Random.h"
   header "RefCount.h"
   header "RuntimeShims.h"

stdlib/public/runtime/ImageInspection.h

@@ -21,7 +21,6 @@
 #ifndef SWIFT_RUNTIME_IMAGEINSPECTION_H
 #define SWIFT_RUNTIME_IMAGEINSPECTION_H
 
-#include "ImageInspectionELF.h"
 #include <cstdint>
 #include <cstddef>
 #if defined(__cplusplus)

stdlib/public/runtime/ImageInspectionELF.cpp

@@ -20,16 +20,17 @@
 
 #if defined(__ELF__)
 
+#include "../SwiftShims/MetadataSections.h"
 #include "ImageInspection.h"
 #include "ImageInspectionELF.h"
 #include <dlfcn.h>
 
 using namespace swift;
 
 namespace {
-static const swift::MetadataSections *registered = nullptr;
+static swift::MetadataSections *registered = nullptr;
 
-void record(const swift::MetadataSections *sections) {
+void record(swift::MetadataSections *sections) {
   if (registered == nullptr) {
     registered = sections;
     sections->next = sections->prev = sections;
@@ -45,7 +46,7 @@ void record(const swift::MetadataSections *sections) {
 void swift::initializeProtocolLookup() {
   const swift::MetadataSections *sections = registered;
   while (true) {
-    const swift::MetadataSections::Range &protocols =
+    const swift::MetadataSectionRange &protocols =
         sections->swift5_protocols;
     if (protocols.length)
       addImageProtocolsBlockCallbackUnsafe(
@@ -59,7 +60,7 @@ void swift::initializeProtocolLookup() {
 void swift::initializeProtocolConformanceLookup() {
   const swift::MetadataSections *sections = registered;
   while (true) {
-    const swift::MetadataSections::Range &conformances =
+    const swift::MetadataSectionRange &conformances =
         sections->swift5_protocol_conformances;
     if (conformances.length)
       addImageProtocolConformanceBlockCallbackUnsafe(
@@ -74,7 +75,7 @@ void swift::initializeProtocolConformanceLookup() {
 void swift::initializeTypeMetadataRecordLookup() {
   const swift::MetadataSections *sections = registered;
   while (true) {
-    const swift::MetadataSections::Range &type_metadata =
+    const swift::MetadataSectionRange &type_metadata =
         sections->swift5_type_metadata;
     if (type_metadata.length)
       addImageTypeMetadataRecordBlockCallbackUnsafe(
@@ -98,7 +99,11 @@ void swift_addNewDSOImage(const void *addr) {
   const swift::MetadataSections *sections =
       static_cast<const swift::MetadataSections *>(addr);
 
-  record(sections);
+  // We cast off the const in order to update the linked list
+  // data structure. This is safe to do since we don't touch 
+  // any other fields.
+  auto casted_sections = const_cast<MetadataSections *>(sections);
+  record(casted_sections);
 
   const auto &protocols_section = sections->swift5_protocols;
   const void *protocols =

stdlib/public/runtime/ImageInspectionELF.h

@@ -34,31 +34,6 @@ struct SectionInfo {
 };
 
 static constexpr const uintptr_t CurrentSectionMetadataVersion = 1;
-
-struct MetadataSections {
-  uintptr_t version;
-  uintptr_t reserved;
-
-  mutable const MetadataSections *next;
-  mutable const MetadataSections *prev;
-
-  struct Range {
-    uintptr_t start;
-    size_t length;
-  };
-
-  Range swift5_protocols;
-  Range swift5_protocol_conformances;
-  Range swift5_type_metadata;
-  Range swift5_typeref;
-  Range swift5_reflstr;
-  Range swift5_fieldmd;
-  Range swift5_assocty;
-  Range swift5_replace;
-  Range swift5_replac2;
-  Range swift5_builtin;
-  Range swift5_capture;
-};
 } // namespace swift
 
 // Called by injected constructors when a dynamic library is loaded.

stdlib/public/runtime/SwiftRT-ELF.cpp

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "ImageInspectionELF.h"
+#include "../SwiftShims/MetadataSections.h"
 
 #include <cstddef>