diff options
Diffstat (limited to 'compiler/rustc_codegen_llvm/src/back/lto.rs')
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/back/lto.rs | 49 |
1 files changed, 0 insertions, 49 deletions
diff --git a/compiler/rustc_codegen_llvm/src/back/lto.rs b/compiler/rustc_codegen_llvm/src/back/lto.rs index d2e01708a..604f68eb6 100644 --- a/compiler/rustc_codegen_llvm/src/back/lto.rs +++ b/compiler/rustc_codegen_llvm/src/back/lto.rs @@ -25,7 +25,6 @@ use std::fs::File; use std::io; use std::iter; use std::path::Path; -use std::ptr; use std::slice; use std::sync::Arc; @@ -709,17 +708,6 @@ pub unsafe fn optimize_thin_module( let llmod = module.module_llvm.llmod(); save_temp_bitcode(cgcx, &module, "thin-lto-input"); - // Before we do much else find the "main" `DICompileUnit` that we'll be - // using below. If we find more than one though then rustc has changed - // in a way we're not ready for, so generate an ICE by returning - // an error. - let mut cu1 = ptr::null_mut(); - let mut cu2 = ptr::null_mut(); - llvm::LLVMRustThinLTOGetDICompileUnit(llmod, &mut cu1, &mut cu2); - if !cu2.is_null() { - return Err(write::llvm_err(&diag_handler, LlvmError::MultipleSourceDiCompileUnit)); - } - // Up next comes the per-module local analyses that we do for Thin LTO. // Each of these functions is basically copied from the LLVM // implementation and then tailored to suit this implementation. Ideally @@ -766,43 +754,6 @@ pub unsafe fn optimize_thin_module( save_temp_bitcode(cgcx, &module, "thin-lto-after-import"); } - // Ok now this is a bit unfortunate. This is also something you won't - // find upstream in LLVM's ThinLTO passes! This is a hack for now to - // work around bugs in LLVM. - // - // First discovered in #45511 it was found that as part of ThinLTO - // importing passes LLVM will import `DICompileUnit` metadata - // information across modules. This means that we'll be working with one - // LLVM module that has multiple `DICompileUnit` instances in it (a - // bunch of `llvm.dbg.cu` members). Unfortunately there's a number of - // bugs in LLVM's backend which generates invalid DWARF in a situation - // like this: - // - // https://bugs.llvm.org/show_bug.cgi?id=35212 - // https://bugs.llvm.org/show_bug.cgi?id=35562 - // - // While the first bug there is fixed the second ended up causing #46346 - // which was basically a resurgence of #45511 after LLVM's bug 35212 was - // fixed. - // - // This function below is a huge hack around this problem. The function - // below is defined in `PassWrapper.cpp` and will basically "merge" - // all `DICompileUnit` instances in a module. Basically it'll take all - // the objects, rewrite all pointers of `DISubprogram` to point to the - // first `DICompileUnit`, and then delete all the other units. - // - // This is probably mangling to the debug info slightly (but hopefully - // not too much) but for now at least gets LLVM to emit valid DWARF (or - // so it appears). Hopefully we can remove this once upstream bugs are - // fixed in LLVM. - { - let _timer = cgcx - .prof - .generic_activity_with_arg("LLVM_thin_lto_patch_debuginfo", thin_module.name()); - llvm::LLVMRustThinLTOPatchDICompileUnit(llmod, cu1); - save_temp_bitcode(cgcx, &module, "thin-lto-after-patch"); - } - // Alright now that we've done everything related to the ThinLTO // analysis it's time to run some optimizations! Here we use the same // `run_pass_manager` as the "fat" LTO above except that we tell it to |