Add a SWIFT_RUNTIME_MACHO_NO_DYLD stdlib mode that doesn't dynamically look up sections in modules, and only assumes a single static module (#33441)

Author: kubamracek

stdlib/CMakeLists.txt

@@ -17,6 +17,10 @@ option(SWIFT_ENABLE_COMPATIBILITY_OVERRIDES
   "Support back-deploying compatibility fixes for newer apps running on older runtimes."
   TRUE)
 
+option(SWIFT_RUNTIME_MACHO_NO_DYLD
+  "Build stdlib assuming the runtime environment uses Mach-O but does not support dynamic modules."
+  FALSE)
+
 #
 # End of user-configurable options.
 #

stdlib/cmake/modules/AddSwiftStdlib.cmake

@@ -302,6 +302,10 @@ function(_add_target_variant_c_compile_flags)
     list(APPEND result "-DSWIFT_RUNTIME_NO_COMPATIBILITY_OVERRIDES")
   endif()
 
+  if(SWIFT_RUNTIME_MACHO_NO_DYLD)
+    list(APPEND result "-DSWIFT_RUNTIME_MACHO_NO_DYLD")
+  endif()
+
   set("${CFLAGS_RESULT_VAR_NAME}" "${result}" PARENT_SCOPE)
 endfunction()
 

stdlib/public/runtime/CMakeLists.txt

@@ -50,6 +50,7 @@ set(swift_runtime_sources
     ImageInspectionMachO.cpp
     ImageInspectionELF.cpp
     ImageInspectionCOFF.cpp
+    ImageInspectionStatic.cpp
     KeyPaths.cpp
     KnownMetadata.cpp
     Metadata.cpp

stdlib/public/runtime/Errors.cpp

@@ -137,7 +137,7 @@ static bool getSymbolNameAddr(llvm::StringRef libraryName,
 
 void swift::dumpStackTraceEntry(unsigned index, void *framePC,
                                 bool shortOutput) {
-#if SWIFT_SUPPORTS_BACKTRACE_REPORTING
+#if SWIFT_SUPPORTS_BACKTRACE_REPORTING && !defined(SWIFT_RUNTIME_MACHO_NO_DYLD)
   SymbolInfo syminfo;
 
   // 0 is failure for lookupSymbol

stdlib/public/runtime/ImageInspectionCommon.h

@@ -19,7 +19,27 @@
 #ifndef SWIFT_RUNTIME_IMAGEINSPECTIONCOMMON_H
 #define SWIFT_RUNTIME_IMAGEINSPECTIONCOMMON_H
 
-#if !defined(__MACH__)
+#if defined(__MACH__)
+
+#include <mach-o/dyld.h>
+
+/// The Mach-O section name for the section containing protocol descriptor
+/// references. This lives within SEG_TEXT.
+#define MachOProtocolsSection "__swift5_protos"
+/// The Mach-O section name for the section containing protocol conformances.
+/// This lives within SEG_TEXT.
+#define MachOProtocolConformancesSection "__swift5_proto"
+/// The Mach-O section name for the section containing type references.
+/// This lives within SEG_TEXT.
+#define MachOTypeMetadataRecordSection "__swift5_types"
+/// The Mach-O section name for the section containing dynamic replacements.
+/// This lives within SEG_TEXT.
+#define MachODynamicReplacementSection "__swift5_replace"
+#define MachODynamicReplacementSomeSection "__swift5_replac2"
+
+#define MachOTextSegment "__TEXT"
+
+#else
 
 #if defined(__ELF__)
 #define SWIFT_REFLECTION_METADATA_ELF_NOTE_MAGIC_STRING "swift_reflection_metadata_magic_string"

stdlib/public/runtime/ImageInspectionMachO.cpp

@@ -18,9 +18,11 @@
 ///
 //===----------------------------------------------------------------------===//
 
-#if defined(__APPLE__) && defined(__MACH__)
+#if defined(__APPLE__) && defined(__MACH__) &&                                 \
+    !defined(SWIFT_RUNTIME_MACHO_NO_DYLD)
 
 #include "ImageInspection.h"
+#include "ImageInspectionCommon.h"
 #include "swift/Runtime/Config.h"
 #include <mach-o/dyld.h>
 #include <mach-o/getsect.h>
@@ -31,21 +33,17 @@
 using namespace swift;
 
 namespace {
-/// The Mach-O section name for the section containing protocol descriptor
-/// references. This lives within SEG_TEXT.
-constexpr const char ProtocolsSection[] = "__swift5_protos";
-/// The Mach-O section name for the section containing protocol conformances.
-/// This lives within SEG_TEXT.
-constexpr const char ProtocolConformancesSection[] = "__swift5_proto";
-/// The Mach-O section name for the section containing type references.
-/// This lives within SEG_TEXT.
-constexpr const char TypeMetadataRecordSection[] = "__swift5_types";
-/// The Mach-O section name for the section containing dynamic replacements.
-/// This lives within SEG_TEXT.
-constexpr const char DynamicReplacementSection[] = "__swift5_replace";
-constexpr const char DynamicReplacementSomeSection[] = "__swift5_replac2";
-
-constexpr const char TextSegment[] = SEG_TEXT;
+
+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 TextSegment[] = MachOTextSegment;
 
 #if __POINTER_WIDTH__ == 64
 using mach_header_platform = mach_header_64;
@@ -182,4 +180,5 @@ void *swift::lookupSection(const char *segment, const char *section, size_t *out
 
 #endif // #ifndef SWIFT_RUNTIME_NO_COMPATIBILITY_OVERRIDES
 
-#endif // defined(__APPLE__) && defined(__MACH__)
+#endif // defined(__APPLE__) && defined(__MACH__) &&
+       // !defined(SWIFT_RUNTIME_MACHO_NO_DYLD)

stdlib/public/runtime/ImageInspectionStatic.cpp

@@ -0,0 +1,77 @@
+//===--- ImageInspectionStatic.cpp - image inspection for static stdlib ---===//
+//
+// 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
+///
+/// Implementation of ImageInspection for static stdlib (no dynamic loader
+/// present) environments. Assumes that only a single image exists in memory.
+///
+//===----------------------------------------------------------------------===//
+
+#if defined(__MACH__) && defined(SWIFT_RUNTIME_MACHO_NO_DYLD)
+
+#include "ImageInspection.h"
+#include "ImageInspectionCommon.h"
+
+using namespace swift;
+
+#define GET_SECTION_START_AND_SIZE(start, size, _seg, _sec)                    \
+  extern void *__s##_seg##_sec __asm("section$start$" _seg "$" _sec);          \
+  extern void *__e##_seg##_sec __asm("section$end$" _seg "$" _sec);            \
+  start = &__s##_seg##_sec;                                                    \
+  size = (char *)&__e##_seg##_sec - (char *)&__s##_seg##_sec;
+
+void swift::initializeProtocolLookup() {
+  void *start;
+  uintptr_t size;
+  GET_SECTION_START_AND_SIZE(start, size, TextSegment, ProtocolsSection);
+  if (start == nullptr || size == 0)
+    return;
+  addImageProtocolsBlockCallbackUnsafe(start, size);
+}
+
+void swift::initializeProtocolConformanceLookup() {
+  void *start;
+  uintptr_t size;
+  GET_SECTION_START_AND_SIZE(start, size, TextSegment,
+                             ProtocolConformancesSection);
+  if (start == nullptr || size == 0)
+    return;
+  addImageProtocolConformanceBlockCallbackUnsafe(start, size);
+}
+void swift::initializeTypeMetadataRecordLookup() {
+  void *start;
+  uintptr_t size;
+  GET_SECTION_START_AND_SIZE(start, size, TextSegment,
+                             TypeMetadataRecordSection);
+  if (start == nullptr || size == 0)
+    return;
+  addImageTypeMetadataRecordBlockCallbackUnsafe(start, size);
+}
+
+void swift::initializeDynamicReplacementLookup() {
+  void *start1;
+  uintptr_t size1;
+  GET_SECTION_START_AND_SIZE(start1, size1, TextSegment,
+                             DynamicReplacementSection);
+  if (start1 == nullptr || size1 == 0)
+    return;
+  void *start2;
+  uintptr_t size2;
+  GET_SECTION_START_AND_SIZE(start2, size2, TextSegment,
+                             DynamicReplacementSection);
+  if (start2 == nullptr || size2 == 0)
+    return;
+  addImageDynamicReplacementBlockCallback(start1, size1, start2, size2);
+}
+
+#endif // defined(__MACH__) && defined(SWIFT_RUNTIME_MACHO_NO_DYLD)

utils/build-presets.ini

@@ -2425,6 +2425,7 @@ build-swift-dynamic-stdlib=0
 build-swift-static-stdlib=1
 swift-objc-interop=0
 swift-enable-compatibility-overrides=0
+swift-runtime-macho-no-dyld=1
 
 [preset: stdlib_S_standalone_minimal_macho_x86_64,build]
 mixin-preset=

utils/build-script-impl

@@ -194,6 +194,7 @@ KNOWN_SETTINGS=(
     stdlib-deployment-targets                     ""                "space-separated list of targets to configure the Swift standard library to be compiled or cross-compiled for"
     swift-objc-interop                            ""                "whether to enable interoperability with Objective-C, default is 1 on Apple platfors, 0 otherwise"
     swift-enable-compatibility-overrides          "1"               "whether to support back-deploying compatibility fixes for newer apps running on older runtimes"
+    swift-runtime-macho-no-dyld                   "0"               "whether to build stdlib assuming the runtime environment does not support dynamic modules"
 
     ## FREESTANDING Stdlib Options
     swift-freestanding-sdk                      ""                "which SDK to use when building the FREESTANDING stdlib"
@@ -1762,6 +1763,7 @@ for host in "${ALL_HOSTS[@]}"; do
                     -DSWIFT_STDLIB_USE_NONATOMIC_RC:BOOL=$(true_false "${SWIFT_STDLIB_USE_NONATOMIC_RC}")
                     -DSWIFT_ENABLE_COMPATIBILITY_OVERRIDES:BOOL=$(true_false "${SWIFT_ENABLE_COMPATIBILITY_OVERRIDES}")
                     -DSWIFT_ENABLE_RUNTIME_FUNCTION_COUNTERS:BOOL=$(true_false "${SWIFT_ENABLE_RUNTIME_FUNCTION_COUNTERS}")
+                    -DSWIFT_RUNTIME_MACHO_NO_DYLD:BOOL=$(true_false "${SWIFT_RUNTIME_MACHO_NO_DYLD}")
                     -DSWIFT_NATIVE_LLVM_TOOLS_PATH:STRING="${native_llvm_tools_path}"
                     -DSWIFT_NATIVE_CLANG_TOOLS_PATH:STRING="${native_clang_tools_path}"
                     -DSWIFT_NATIVE_SWIFT_TOOLS_PATH:STRING="${native_swift_tools_path}"