Merge pull request #68669 from al45tair/eng/PR-115774613

[Linux] Force the inclusion of the backtracing code when static linking.

Author: al45tair

cmake/modules/AddSwift.cmake

@@ -543,6 +543,7 @@ function(_add_swift_runtime_link_flags target relpath_to_lib_dir bootstrapping)
       get_filename_component(swift_bin_dir ${SWIFT_EXEC_FOR_SWIFT_MODULES} DIRECTORY)
       get_filename_component(swift_dir ${swift_bin_dir} DIRECTORY)
       set(host_lib_dir "${swift_dir}/lib/swift/${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}")
+      set(swiftrt "${host_lib_dir}/${SWIFT_HOST_VARIANT_ARCH}/swiftrt.o")
 
       target_link_libraries(${target} PRIVATE ${swiftrt})
       target_link_libraries(${target} PRIVATE "swiftCore")

stdlib/public/runtime/SwiftRT-ELF-WASM.cpp

@@ -12,6 +12,7 @@
 
 #include "ImageInspectionCommon.h"
 #include "swift/shims/MetadataSections.h"
+#include "swift/Runtime/Backtrace.h"
 
 #include <cstddef>
 #include <new>
@@ -24,6 +25,11 @@ extern "C" const char __dso_handle[];
 static constexpr const void *__dso_handle = nullptr;
 #endif
 
+// Drag in a symbol from the backtracer, to force the static linker to include
+// the code.
+static const void *__backtraceRef __attribute__((used))
+  = (const void *)swift::runtime::backtrace::_swift_backtrace_isThunkFunction;
+
 // Create empty sections to ensure that the start/stop symbols are synthesized
 // by the linker.  Otherwise, we may end up with undefined symbol references as
 // the linker table section was never constructed.

test/Backtracing/CrashStatic.swift

@@ -0,0 +1,60 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %s -parse-as-library %import-static-libdispatch -Onone -static-stdlib -g -o %t/CrashStatic
+// RUN: %target-codesign %t/CrashStatic
+// RUN: (env SWIFT_BACKTRACE=enable=yes,cache=no,swift-backtrace=%backtracer %target-run %t/CrashStatic 2>&1 || true) | %FileCheck %s
+
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+// UNSUPPORTED: asan
+// REQUIRES: executable_test
+// REQUIRES: backtracing
+// REQUIRES: static_stdlib
+// REQUIRES: OS=linux-gnu
+
+func level1() {
+  level2()
+}
+
+func level2() {
+  level3()
+}
+
+func level3() {
+  level4()
+}
+
+func level4() {
+  level5()
+}
+
+func level5() {
+  print("About to crash")
+  let ptr = UnsafeMutablePointer<Int>(bitPattern: 4)!
+  ptr.pointee = 42
+}
+
+@main
+struct CrashStatic {
+  static func main() {
+    level1()
+  }
+}
+
+// CHECK: *** Program crashed: Bad pointer dereference at 0x{{0+}}4 ***
+
+// CHECK: Thread 0 {{(".*" )?}}crashed:
+
+// CHECK: 0               0x{{[0-9a-f]+}} level5() + {{[0-9]+}} in CrashStatic at {{.*}}/CrashStatic.swift:33:15
+// CHECK-NEXT: 1 [ra]          0x{{[0-9a-f]+}} level4() + {{[0-9]+}} in CrashStatic at {{.*}}/CrashStatic.swift:27:3
+// CHECK-NEXT: 2 [ra]          0x{{[0-9a-f]+}} level3() + {{[0-9]+}} in CrashStatic at {{.*}}/CrashStatic.swift:23:3
+// CHECK-NEXT: 3 [ra]          0x{{[0-9a-f]+}} level2() + {{[0-9]+}} in CrashStatic at {{.*}}/CrashStatic.swift:19:3
+// CHECK-NEXT: 4 [ra]          0x{{[0-9a-f]+}} level1() + {{[0-9]+}} in CrashStatic at {{.*}}/CrashStatic.swift:15:3
+// CHECK-NEXT: 5 [ra]          0x{{[0-9a-f]+}} static CrashStatic.main() + {{[0-9]+}} in CrashStatic at {{.*}}/CrashStatic.swift:39:5
+// CHECK-NEXT: 6 [ra] [system] 0x{{[0-9a-f]+}} static CrashStatic.$main() + {{[0-9]+}} in CrashStatic at {{.*}}/<compiler-generated>
+// CHECK-NEXT: 7 [ra] 0x{{[0-9a-f]+}} main + {{[0-9]+}} in CrashStatic at {{.*}}/CrashStatic.swift
+
+// CHECK: Registers:
+
+// CHECK: Images ({{[0-9]+}} omitted):
+
+// CHECK: {{0x[0-9a-f]+}}–{{0x[0-9a-f]+}}{{ +}}{{([0-9a-f]+|<no build ID>)}}{{ +}}CrashStatic{{ +}}{{.*}}/CrashStatic

test/lit.cfg

@@ -354,6 +354,7 @@ config.scale_test = make_path(config.swift_utils, 'scale-test')
 config.PathSanitizingFileCheck = make_path(config.swift_utils, 'PathSanitizingFileCheck')
 config.swift_bin_dir = make_path(config.swift, '..', '..', 'bin')
 config.swift_lib_dir = make_path(config.swift, '..', '..', 'lib')
+config.swift_libexec_dir = make_path(config.swift, '..', '..', 'libexec')
 config.swift_share_dir = make_path(config.swift, '..', '..', 'share')
 config.round_trip_syntax_test = make_path(config.swift_utils, 'round-trip-syntax-test')
 config.refactor_check_compiles = make_path(config.swift_utils, 'refactor-check-compiles.py')
@@ -588,6 +589,7 @@ else:
 config.substitutions.append( ('%llvm_obj_root', config.llvm_obj_root) )
 config.substitutions.append( ('%swift-bin-dir', config.swift_bin_dir) )
 config.substitutions.append( ('%swift-lib-dir', config.swift_lib_dir) )
+config.substitutions.append( ('%swift-libexec-dir', config.swift_lib_dir) )
 config.substitutions.append( ('%swift-share-dir', config.swift_share_dir) )
 config.substitutions.append( ('%swift-plugin-dir', config.swift_plugin_dir) )
 config.substitutions.append( ('%llvm_src_root', config.llvm_src_root) )
@@ -1998,6 +2000,10 @@ if run_vendor == 'apple':
         config.available_features.add('back_deploy_concurrency')
         concurrency_back_deploy_path = os.path.join(os.path.dirname(swift_obj_root), os.path.basename(swift_obj_root).replace("swift-", "backdeployconcurrency-"), 'lib', 'swift-5.5', xcrun_sdk_name)
 
+backtracer_path = make_path(config.swift_libexec_dir, 'swift',
+                            config.target_sdk_name, 'swift-backtrace')
+config.substitutions.append(('%backtracer', backtracer_path))
+
 def os_stdlib_paths():
     if run_vendor == 'apple':
         if run_os == 'maccatalyst':