Linker crashes when building tools

Development Compiler
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1

I think the linker is crashing when attempting to build some of the compiler repository tools.

I just rebased to the latest commit on main, so it's at 36a15ceaf4230e658a9453d2f14532bb99fd5dd4, and I ran update-checkout and deleted the previous build directory, so everything should be fresh.

macOS Sonoma 14.0 (23A344)
M1 Pro
Xcode 15.0 (15A240d)

[1351/2166][ 62%][557.124s] Linking CXX executable bin/lldb-moduleimport-test
FAILED: bin/lldb-moduleimport-test 
<...>
0  0x102b3f648  __assert_rtn + 72
1  0x102afa0f0  ___Z13dispatchApplyIRKmZ15dispatchForEachIKN6mach_o13CompactUnwind11Diff24FixupEZNK2ld16LayoutExecutable18writeCompactUnwindENSt3__14spanIhLm18446744073709551615EEEyRKNS7_13SectionLayoutEE4$_26EvNSA_IT_Lm18446744073709551615EEEmT0_EUlmE_EvOSG_SI__block_invoke + 0
2  0x18c541950  _dispatch_client_callout2 + 20
3  0x18c5561a4  _dispatch_apply_invoke_and_wait + 176
4  0x18c555464  _dispatch_apply_with_attr_f + 1176
5  0x18c555650  dispatch_apply + 96
6  0x102afa398  ld::LayoutExecutable::writeContentWithoutLinkEdit(std::__1::span<unsigned char, 18446744073709551615ul>, unsigned long long) + 672
7  0x102b00020  ld::LayoutExecutable::writeToFile(char const*) + 15248
8  0x102ab22e8  main + 9424
ld: Assertion failed: (false && "compact unwind compressed function offset doesn't fit in 24 bits"), function operator(), file Layout.cpp, line 5758.
clang: error: linker command failed with exit code 1 (use -v to see invocation)

And the same for bin/swift-refactor.

Build command:

utils/build-script \
  --skip-ios --skip-watchos --skip-tvos --swift-darwin-supported-archs "$(uname -m)" \
  --sccache --release-debuginfo --debug-swift --swift-disable-dead-stripping

Apparently this is something of a known issue in Xcode 15, and there are suggestions that adding the -ld_classic linker flag might resolve it. I checked the release notes for 15.0.1 and 15.1 beta, and neither of them mention it.

Has anybody else encountered this issue? What did you do to resolve it?

3 Likes
2

Seems to be not fixed as of Xcode 15.1.

What is the correct way to pass -ld_classic through build-script?

I've tried:

  ...
  --extra-cmake-options " -DCMAKE_EXE_LINKER_FLAGS_INIT=-ld_classic" \
  --extra-cmake-options " -DCMAKE_STATIC_LINKER_FLAGS_INIT=-ld_classic" \
  --extra-cmake-options " -DCMAKE_MODULE_LINKER_FLAGS_INIT=-ld_classic" \

, but it did not work.

1 Like
3

For anyone who is working on the compiler and encounters this, cd to your swift build directory and build just the standard library (which builds the compiler) with ninja swift-stdlib-macosx, not everything like build-script does. Chances are you don’t need lldb-moduleimport-test anyway.

1 Like
4

Settings it through LDFLAGS seems to have worked:

LDFLAGS="-ld_classic" swift/utils/build-script ...

After initial configuration using build-script I see it being applied to incremental builds with ninja even if LDFLAGS is no longer set in the environment.

1 Like
5

Ran into the same issue, and @anthonylatsis's solution worked for me! In my case (Xcode 15.1) with a clean build, I stopped the build-script once it built the compiler and then built just the standard library with ninja.