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Remove the ThinLTO CU hack

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This reverts #46722, commit e0ab5d5feb.

Since #111167, commit 10b69dde3f, we are
generating DWARF subprograms in a way that is meant to be more compatible
with LLVM's expectations, so hopefully we don't need this workaround
rewriting CUs anymore.
This commit is contained in:
Josh Stone 2023-05-04 17:20:49 -07:00
parent ce042889f7
commit c836c24994
3 changed files with 0 additions and 112 deletions
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57
compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
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@ -1460,63 +1460,6 @@ LLVMRustGetBitcodeSliceFromObjectData(const char *data,
return BitcodeOrError->getBufferStart();
}
// Rewrite all `DICompileUnit` pointers to the `DICompileUnit` specified. See
// the comment in `back/lto.rs` for why this exists.
extern "C" void
LLVMRustThinLTOGetDICompileUnit(LLVMModuleRef Mod,
DICompileUnit **A,
DICompileUnit **B) {
Module *M = unwrap(Mod);
DICompileUnit **Cur = A;
DICompileUnit **Next = B;
for (DICompileUnit *CU : M->debug_compile_units()) {
*Cur = CU;
Cur = Next;
Next = nullptr;
if (Cur == nullptr)
break;
}
}
// Rewrite all `DICompileUnit` pointers to the `DICompileUnit` specified. See
// the comment in `back/lto.rs` for why this exists.
extern "C" void
LLVMRustThinLTOPatchDICompileUnit(LLVMModuleRef Mod, DICompileUnit *Unit) {
Module *M = unwrap(Mod);
// If the original source module didn't have a `DICompileUnit` then try to
// merge all the existing compile units. If there aren't actually any though
// then there's not much for us to do so return.
if (Unit == nullptr) {
for (DICompileUnit *CU : M->debug_compile_units()) {
Unit = CU;
break;
}
if (Unit == nullptr)
return;
}
// Use LLVM's built-in `DebugInfoFinder` to find a bunch of debuginfo and
// process it recursively. Note that we used to specifically iterate over
// instructions to ensure we feed everything into it, but `processModule`
// started doing this the same way in LLVM 7 (commit d769eb36ab2b8).
DebugInfoFinder Finder;
Finder.processModule(*M);
// After we've found all our debuginfo, rewrite all subprograms to point to
// the same `DICompileUnit`.
for (auto &F : Finder.subprograms()) {
F->replaceUnit(Unit);
}
// Erase any other references to other `DICompileUnit` instances, the verifier
// will later ensure that we don't actually have any other stale references to
// worry about.
auto *MD = M->getNamedMetadata("llvm.dbg.cu");
MD->clearOperands();
MD->addOperand(Unit);
}
// Computes the LTO cache key for the provided 'ModId' in the given 'Data',
// storing the result in 'KeyOut'.
// Currently, this cache key is a SHA-1 hash of anything that could affect