Reapply [cxx-interop][libswift] Use std::string instead of BridgedStringRef

SwiftCompilerSources/CMakeLists.txt

@@ -89,14 +89,27 @@ function(add_swift_compiler_modules_library name)
 
   if(SWIFT_HOST_VARIANT_SDK IN_LIST SWIFT_DARWIN_PLATFORMS)
     set(deployment_version "${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_DEPLOYMENT_VERSION}")
-    set(sdk_option "-sdk" "${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_ARCH_${SWIFT_HOST_VARIANT_ARCH}_PATH}")
+    set(sdk_path "${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_ARCH_${SWIFT_HOST_VARIANT_ARCH}_PATH}")
+    set(sdk_option "-sdk" "${sdk_path}")
     if(${BOOTSTRAPPING_MODE} STREQUAL "CROSSCOMPILE-WITH-HOSTLIBS")
       # Let the cross-compiled compile don't pick up the compiled stdlib by providing
       # an (almost) empty resource dir.
       # The compiler will instead pick up the stdlib from the SDK.
       get_filename_component(swift_exec_bin_dir ${ALS_SWIFT_EXEC} DIRECTORY)
       set(sdk_option ${sdk_option} "-resource-dir" "${swift_exec_bin_dir}/../bootstrapping0/lib/swift")
     endif()
+    if(NOT EXISTS "${sdk_path}/usr/include/c++")
+      # Darwin SDKs in Xcode 12 or older do not include libc++, which prevents clang from finding libc++ when invoked
+      # from ClangImporter. This results in build errors. To workaround this, let's explicitly pass the path to libc++
+      # to clang.
+      message(WARNING "Building with an outdated Darwin SDK: libc++ missing from the ${SWIFT_HOST_VARIANT_SDK} SDK. Will use libc++ from the toolchain.")
+      get_filename_component(absolute_libcxx_path "${CMAKE_C_COMPILER}/../../include/c++/v1" REALPATH)
+      if (EXISTS "${absolute_libcxx_path}")
+        set(sdk_option ${sdk_option} "-Xcc" "-isystem" "-Xcc" "${absolute_libcxx_path}")
+      else()
+        message(ERROR "libc++ not found in the toolchain.")
+      endif()
+    endif()
   elseif(${BOOTSTRAPPING_MODE} STREQUAL "CROSSCOMPILE")
     set(sdk_option "-sdk" "${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_ARCH_${SWIFT_HOST_VARIANT_ARCH}_PATH}")
     get_filename_component(swift_exec_bin_dir ${ALS_SWIFT_EXEC} DIRECTORY)
@@ -212,6 +225,10 @@ else()
         list(APPEND b0_deps swiftDarwin-bootstrapping0)
         list(APPEND b1_deps swiftDarwin-bootstrapping1)
       endif()
+      if(${SWIFT_HOST_VARIANT_SDK} IN_LIST SWIFT_LIBSTDCXX_PLATFORMS)
+        list(APPEND b0_deps copy-libstdcxx-modulemap-bootstrapping0 copy-libstdcxx-header-bootstrapping0)
+        list(APPEND b1_deps copy-libstdcxx-modulemap-bootstrapping1 copy-libstdcxx-header-bootstrapping1)
+      endif()
     endif()
     if(SWIFT_HOST_VARIANT_SDK IN_LIST SWIFT_DARWIN_PLATFORMS)
       set(platform ${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR})

SwiftCompilerSources/Sources/SIL/BasicBlock.swift

@@ -25,7 +25,8 @@ final public class BasicBlock : ListNode, CustomStringConvertible, HasName {
   public var function: Function { SILBasicBlock_getFunction(bridged).function }
 
   public var description: String {
-    SILBasicBlock_debugDescription(bridged).takeString()
+    var s = SILBasicBlock_debugDescription(bridged)
+    return String(cString: s.c_str())
   }
 
   public var arguments: ArgumentArray { ArgumentArray(block: self) }

SwiftCompilerSources/Sources/SIL/Function.swift

@@ -21,7 +21,8 @@ final public class Function : CustomStringConvertible, HasName {
   }
 
   final public var description: String {
-    return SILFunction_debugDescription(bridged).takeString()
+    var s = SILFunction_debugDescription(bridged)
+    return String(cString: s.c_str())
   }
 
   public var entryBlock: BasicBlock {

SwiftCompilerSources/Sources/SIL/GlobalVariable.swift

@@ -19,7 +19,8 @@ final public class GlobalVariable : CustomStringConvertible, HasName {
   }
 
   public var description: String {
-    return SILGlobalVariable_debugDescription(bridged).takeString()
+    var s = SILGlobalVariable_debugDescription(bridged)
+    return String(cString: s.c_str())
   }
 
   // TODO: initializer instructions

SwiftCompilerSources/Sources/SIL/Instruction.swift

@@ -38,7 +38,8 @@ public class Instruction : ListNode, CustomStringConvertible, Hashable {
   final public var function: Function { block.function }
 
   final public var description: String {
-    SILNode_debugDescription(bridgedNode).takeString()
+    var s = SILNode_debugDescription(bridgedNode)
+    return String(cString: s.c_str())
   }
 
   final public var operands: OperandArray {
@@ -135,7 +136,8 @@ public class SingleValueInstruction : Instruction, Value {
 
 public final class MultipleValueInstructionResult : Value {
   final public var description: String {
-    SILNode_debugDescription(bridgedNode).takeString()
+    var s = SILNode_debugDescription(bridgedNode)
+    return String(cString: s.c_str())
   }
 
   public var instruction: Instruction {

SwiftCompilerSources/Sources/SIL/Value.swift

@@ -21,7 +21,8 @@ public protocol Value : AnyObject, CustomStringConvertible {
 
 extension Value {
   public var description: String {
-    SILNode_debugDescription(bridgedNode).takeString()
+    var s = SILNode_debugDescription(bridgedNode)
+    return String(cString: s.c_str())
   }
 
   public var uses: UseList {

cmake/modules/AddSwift.cmake

@@ -3,6 +3,7 @@ include(SwiftList)
 include(SwiftXcodeSupport)
 include(SwiftWindowsSupport)
 include(SwiftAndroidSupport)
+include(SwiftCXXUtils)
 
 function(_swift_gyb_target_sources target scope)
   file(GLOB GYB_UNICODE_DATA ${SWIFT_SOURCE_DIR}/utils/UnicodeData/*)

cmake/modules/SwiftCXXUtils.cmake

@@ -0,0 +1,7 @@
+# Platforms that use libstdc++ as the system-wide default C++ standard library.
+set(SWIFT_LIBSTDCXX_PLATFORMS
+    "LINUX"
+    "FREEBSD"
+    "OPENBSD"
+    "CYGWIN"
+    "HAIKU")

include/swift/SIL/SILBridging.h

@@ -17,10 +17,7 @@
 #include "swift/Basic/BridgedSwiftObject.h"
 #include <stdbool.h>
 #include <stddef.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
+#include <string>
 
 SWIFT_BEGIN_NULLABILITY_ANNOTATIONS
 
@@ -181,7 +178,7 @@ void PassContext_eraseInstruction(BridgedPassContext passContext,
                                   BridgedInstruction inst);
 
 BridgedStringRef SILFunction_getName(BridgedFunction function);
-BridgedStringRef SILFunction_debugDescription(BridgedFunction function);
+std::string SILFunction_debugDescription(BridgedFunction function);
 OptionalBridgedBasicBlock SILFunction_firstBlock(BridgedFunction function);
 OptionalBridgedBasicBlock SILFunction_lastBlock(BridgedFunction function);
 SwiftInt SILFunction_numIndirectResultArguments(BridgedFunction function);
@@ -192,12 +189,12 @@ BridgedType SILFunction_getSILResultType(BridgedFunction function);
 SwiftInt SILFunction_isSwift51RuntimeAvailable(BridgedFunction function);
 
 BridgedStringRef SILGlobalVariable_getName(BridgedGlobalVar global);
-BridgedStringRef SILGlobalVariable_debugDescription(BridgedGlobalVar global);
+std::string SILGlobalVariable_debugDescription(BridgedGlobalVar global);
 
 OptionalBridgedBasicBlock SILBasicBlock_next(BridgedBasicBlock block);
 OptionalBridgedBasicBlock SILBasicBlock_previous(BridgedBasicBlock block);
 BridgedFunction SILBasicBlock_getFunction(BridgedBasicBlock block);
-BridgedStringRef SILBasicBlock_debugDescription(BridgedBasicBlock block);
+std::string SILBasicBlock_debugDescription(BridgedBasicBlock block);
 OptionalBridgedInstruction SILBasicBlock_firstInst(BridgedBasicBlock block);
 OptionalBridgedInstruction SILBasicBlock_lastInst(BridgedBasicBlock block);
 SwiftInt SILBasicBlock_getNumArguments(BridgedBasicBlock block);
@@ -212,7 +209,7 @@ OptionalBridgedOperand Operand_nextUse(BridgedOperand);
 BridgedInstruction Operand_getUser(BridgedOperand);
 SwiftInt Operand_isTypeDependent(BridgedOperand);
 
-BridgedStringRef SILNode_debugDescription(BridgedNode node);
+std::string SILNode_debugDescription(BridgedNode node);
 BridgedFunction SILNode_getFunction(BridgedNode node);
 OptionalBridgedOperand SILValue_firstUse(BridgedValue value);
 BridgedType SILValue_getType(BridgedValue value);
@@ -321,8 +318,4 @@ BridgedInstruction SILBuilder_createApply(BridgedInstruction insertionPoint,
 
 SWIFT_END_NULLABILITY_ANNOTATIONS
 
-#ifdef __cplusplus
-} // extern "C"
-#endif
-
 #endif

lib/SIL/Utils/SILBridging.cpp

@@ -16,6 +16,7 @@
 #include "swift/SIL/SILBridgingUtils.h"
 #include "swift/SIL/SILGlobalVariable.h"
 #include "swift/SIL/SILBuilder.h"
+#include <string>
 
 using namespace swift;
 
@@ -149,11 +150,12 @@ BridgedStringRef SILFunction_getName(BridgedFunction function) {
   return getBridgedStringRef(castToFunction(function)->getName());
 }
 
-BridgedStringRef SILFunction_debugDescription(BridgedFunction function) {
+std::string SILFunction_debugDescription(BridgedFunction function) {
   std::string str;
   llvm::raw_string_ostream os(str);
   castToFunction(function)->print(os);
-  return getCopiedBridgedStringRef(str, /*removeTrailingNewline*/ true);
+  str.pop_back(); // Remove trailing newline.
+  return str;
 }
 
 OptionalBridgedBasicBlock SILFunction_firstBlock(BridgedFunction function) {
@@ -239,11 +241,12 @@ BridgedFunction SILBasicBlock_getFunction(BridgedBasicBlock block) {
   return {castToBasicBlock(block)->getParent()};
 }
 
-BridgedStringRef SILBasicBlock_debugDescription(BridgedBasicBlock block) {
+std::string SILBasicBlock_debugDescription(BridgedBasicBlock block) {
   std::string str;
   llvm::raw_string_ostream os(str);
   castToBasicBlock(block)->print(os);
-  return getCopiedBridgedStringRef(str, /*removeTrailingNewline*/ true);
+  str.pop_back(); // Remove trailing newline.
+  return str;
 }
 
 OptionalBridgedInstruction SILBasicBlock_firstInst(BridgedBasicBlock block) {
@@ -308,11 +311,12 @@ SwiftInt SILArgument_isExclusiveIndirectParameter(BridgedArgument argument) {
 static_assert(BridgedOperandSize == sizeof(Operand),
               "wrong bridged Operand size");
 
-BridgedStringRef SILNode_debugDescription(BridgedNode node) {
+std::string SILNode_debugDescription(BridgedNode node) {
   std::string str;
   llvm::raw_string_ostream os(str);
   castToSILNode(node)->print(os);
-  return getCopiedBridgedStringRef(str, /*removeTrailingNewline*/ true);
+  str.pop_back(); // Remove trailing newline.
+  return str;
 }
 
 BridgedFunction SILNode_getFunction(BridgedNode node) {
@@ -465,11 +469,12 @@ BridgedStringRef SILGlobalVariable_getName(BridgedGlobalVar global) {
   return getBridgedStringRef(castToGlobal(global)->getName());
 }
 
-BridgedStringRef SILGlobalVariable_debugDescription(BridgedGlobalVar global) {
+std::string SILGlobalVariable_debugDescription(BridgedGlobalVar global) {
   std::string str;
   llvm::raw_string_ostream os(str);
   castToGlobal(global)->print(os);
-  return getCopiedBridgedStringRef(str, /*removeTrailingNewline*/ true);
+  str.pop_back(); // Remove trailing newline.
+  return str;
 }
 
 //===----------------------------------------------------------------------===//

stdlib/public/Cxx/CMakeLists.txt

@@ -1,10 +1,6 @@
 set(libstdcxx_modulemap_target_list)
 foreach(sdk ${SWIFT_SDKS})
-  if(NOT "${sdk}" STREQUAL "LINUX" AND
-      NOT "${sdk}" STREQUAL "FREEBSD" AND
-      NOT "${sdk}" STREQUAL "OPENBSD" AND
-      NOT "${sdk}" STREQUAL "CYGWIN" AND
-      NOT "${sdk}" STREQUAL "HAIKU")
+  if(NOT ${sdk} IN_LIST SWIFT_LIBSTDCXX_PLATFORMS)
     continue()
   endif()
 
@@ -89,6 +85,38 @@ foreach(sdk ${SWIFT_SDKS})
           DESTINATION "lib/swift_static/${arch_subdir}"
           COMPONENT sdk-overlay)
     endif()
+
+    if(${BOOTSTRAPPING_MODE} MATCHES "BOOTSTRAPPING.*")
+      foreach(bootstrapping "0" "1")
+        get_bootstrapping_path(bootstrapping_dir ${module_dir} ${bootstrapping})
+        set(libstdcxx_modulemap_out_bootstrapping "${bootstrapping_dir}/libstdcxx.modulemap")
+        set(libstdcxx_header_out_bootstrapping "${bootstrapping_dir}/libstdcxx.h")
+
+        add_custom_command_target(unused_var
+            COMMAND
+            "${CMAKE_COMMAND}" "-E" "make_directory" "${bootstrapping_dir}"
+            COMMAND
+            "${CMAKE_COMMAND}" "-E" "copy"
+            "${CMAKE_CURRENT_SOURCE_DIR}/${libstdcxx_modulemap}" "${libstdcxx_modulemap_out_bootstrapping}"
+
+            CUSTOM_TARGET_NAME "copy-libstdcxx-modulemap-bootstrapping${bootstrapping}"
+            OUTPUT "${libstdcxx_modulemap_out_bootstrapping}"
+            DEPENDS ${libstdcxx_modulemap}
+            COMMENT "Copying libstdcxx modulemap to resources for bootstrapping${bootstrapping}")
+
+        add_custom_command_target(unused_var
+            COMMAND
+            "${CMAKE_COMMAND}" "-E" "make_directory" "${bootstrapping_dir}"
+            COMMAND
+            "${CMAKE_COMMAND}" "-E" "copy"
+            "${CMAKE_CURRENT_SOURCE_DIR}/${libstdcxx_header}" "${libstdcxx_header_out_bootstrapping}"
+
+            CUSTOM_TARGET_NAME "copy-libstdcxx-header-bootstrapping${bootstrapping}"
+            OUTPUT "${libstdcxx_header_out_bootstrapping}"
+            DEPENDS ${libstdcxx_header}
+            COMMENT "Copying libstdcxx header to resources for bootstrapping${bootstrapping}")
+      endforeach()
+    endif()
   endforeach()
 endforeach()
 add_custom_target(libstdcxx-modulemap DEPENDS ${libstdcxx_modulemap_target_list})