[MLIR][TranslateToLLVM] cannot link module during translation

[SchrodingerZhu]

Consider:

struct ReussirLLVMTranslation : public mlir::LLVMTranslationDialectInterface {
  using LLVMTranslationDialectInterface::LLVMTranslationDialectInterface;

  LogicalResult
  convertOperation(Operation *op, llvm::IRBuilderBase &builder,
                   LLVM::ModuleTranslation &state) const override {
    if (auto polyffi = dyn_cast<ReussirPolyFFIOp>(op)) {
      if (!polyffi.getCompiledModule())
        return op->emitError("PolyFFI operation has no compiled module");
      auto denseI8array =
          dyn_cast<DenseElementsAttr>(*polyffi.getCompiledModule());
      if (!denseI8array)
        return op->emitError("compiledModule is not a DenseElementsAttr");
      llvm::ArrayRef<char> bitcodeData = denseI8array.getRawData();
      std::unique_ptr<llvm::MemoryBuffer> memBuffer =
          llvm::MemoryBuffer::getMemBuffer(
              llvm::StringRef(bitcodeData.data(), bitcodeData.size()));
      llvm::Expected<std::unique_ptr<llvm::Module>> moduleOrErr =
          llvm::parseBitcodeFile(memBuffer->getMemBufferRef(),
                                 state.getLLVMContext());
      if (!moduleOrErr)
        return op->emitError("PolyFFI operation has invalid bitcode");
      std::unique_ptr<llvm::Module> innerModule = std::move(*moduleOrErr);
      auto layout = state.getLLVMModule()->getDataLayout();
      innerModule->setDataLayout(layout);
      bool flag = llvm::Linker::linkModules(*state.getLLVMModule(),
                                            std::move(innerModule));
      if (flag)
        return op->emitError("PolyFFI operation cannot be linked");
      return success();
    }
    return failure();
  }
};

This approach will leave the ModuleTranslation in a broken state where further operation translation can abort the program.

I wonder if we can have a way to recover the state after linker invocation.

Of cuz, a way to avoid this is to use customized translation rather than the LLVMTranslationDialectInterface, but that seems to be requiring more efforts.

[llvmbot]

@llvm/issue-subscribers-mlir

Author: Schrodinger ZHU Yifan (SchrodingerZhu)

Consider: ```c++ struct ReussirLLVMTranslation : public mlir::LLVMTranslationDialectInterface { using LLVMTranslationDialectInterface::LLVMTranslationDialectInterface;

LogicalResult
convertOperation(Operation *op, llvm::IRBuilderBase &builder,
LLVM::ModuleTranslation &state) const override {
if (auto polyffi = dyn_cast<ReussirPolyFFIOp>(op)) {
if (!polyffi.getCompiledModule())
return op->emitError("PolyFFI operation has no compiled module");
auto denseI8array =
dyn_cast<DenseElementsAttr>(*polyffi.getCompiledModule());
if (!denseI8array)
return op->emitError("compiledModule is not a DenseElementsAttr");
llvm::ArrayRef<char> bitcodeData = denseI8array.getRawData();
std::unique_ptr<llvm::MemoryBuffer> memBuffer =
llvm::MemoryBuffer::getMemBuffer(
llvm::StringRef(bitcodeData.data(), bitcodeData.size()));
llvm::Expected<std::unique_ptr<llvm::Module>> moduleOrErr =
llvm::parseBitcodeFile(memBuffer->getMemBufferRef(),
state.getLLVMContext());
if (!moduleOrErr)
return op->emitError("PolyFFI operation has invalid bitcode");
std::unique_ptr<llvm::Module> innerModule = std::move(*moduleOrErr);
auto layout = state.getLLVMModule()->getDataLayout();
innerModule->setDataLayout(layout);
bool flag = llvm::Linker::linkModules(*state.getLLVMModule(),
std::move(innerModule));
if (flag)
return op->emitError("PolyFFI operation cannot be linked");
return success();
}
return failure();
}
};

This approach will leave the ModuleTranslation in a broken state where further operation translation can abort the program.

I wonder if we can have a way to recover the state after linker invocation.

Of cuz, a way to avoid this is to use customized translation rather than the LLVMTranslationDialectInterface, but that seems to be requiring more efforts.
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