c2rust fails to build with LLVM 15

[jrmuizel]

 --- stderr
  CMake Warning:
    Manually-specified variables were not used by the project:

      CMAKE_ASM_COMPILER
      CMAKE_ASM_FLAGS


  * Closing connection 0
  * Closing connection 1
  /Users/jrmuizel/.cargo/git/checkouts/c2rust-2a3ef4c32beab81a/1fddfc4/c2rust-ast-exporter/src/AstExporter.cpp:2270:52: error: no member named 'Ascii' in 'clang::StringLiteral::StringKind'
              case clang::StringLiteral::StringKind::Ascii:
                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
  1 error generated.
  make[3]: *** [CMakeFiles/clangAstExporter.dir/AstExporter.cpp.o] Error 1
  make[2]: *** [CMakeFiles/clangAstExporter.dir/all] Error 2
  make[1]: *** [CMakeFiles/clangAstExporter.dir/rule] Error 2

[kkysen]

On Linux it builds with LLVM 11 and 12 fine. I haven't tested LLVM 15 before.

You're getting this same error for LLVM 11, 12, and 15 but not 13 and 14?

[jrmuizel]

I didn't have 13 and 14 so didn't try them. The error seems to be the same in 11, 12 and 15. Using LLVM 8 worked though.

I was using:

LLVM_CONFIG_PATH=/usr/local/opt/llvm/bin/llvm-config cargo install --git https://github.com/immunant/c2rust.git c2rust
LLVM_CONFIG_PATH=/usr/local/opt/llvm@11/bin/llvm-config cargo install --git https://github.com/immunant/c2rust.git c2rust
LLVM_CONFIG_PATH=/usr/local/opt/llvm@15/bin/llvm-config cargo install --git https://github.com/immunant/c2rust.git c2rust

[thedataking]

I'm not able to reproduce with LLVM 11, 12 on Linux (Ubuntu 22.10) or LLVM 11 on MacOS Monterey. Update: I can reproduce with LLVM 15 on MacOS.

It looks like the definition of clang::StringLiteral::StringKindin Expr.h changed. It seems that the Ascii variant was renamed to Ordinary when LLVM 15 was released so I think that's the most likely explanation for this issue.

Are you able to run down the exact copy of Expr.h you are building against? Were you doing a clean build when hitting the problem on LLVM 11 and 12?

[thedataking]

@jrmuizel can you try LLVM_CONFIG_PATH=/usr/local/opt/llvm@15/bin/llvm-config cargo build on feature/llvm-15.0.0 and let me know if that works? I'm hitting a weird linker issue on MacOS to I switched to link dynamically instead of statically.

With static linking on MacOS, I'm seeing this error related to -opaque-pointers (see change in build.rs):

ld: in /usr/local/Cellar/llvm/15.0.0/lib/libclangAST.a(Stmt.cpp.o), could not parse object file /usr/local/Cellar/llvm/15.0.0/lib/libclangAST.a(Stmt.cpp.o): 'Opaque pointers are only supported in -opaque-pointers mode (Producer: 'LLVM15.0.0' Reader: 'LLVM APPLE_1_1400.0.29.102_0')', using libLTO version 'LLVM version 14.0.0, (clang-1400.0.29.102)' for architecture x86_64

[pmembrey]

@thedataking I tried the feature/llvm-15.0.0 branch and I was able to build it successfully with cargo build. I'm using version 15.0.1 of llvm on an M1 Mac.

In case it helps someone, on an M1 Mac, homebrew uses /opt/homebrew/ as its default location. I used this command to build:

LLVM_CONFIG_PATH=/opt/homebrew/Cellar/llvm/15.0.1/bin/llvm-config cargo build