[Xtensa 3/10] Add initial version of the Xtensa backend.

[andreisfr]

Summary

Add Xtensa MCTargetDesc stub. Add XtensaTargetMachine and XtensaTargetInfo.
Modify llib/Target/LLVMBuild.txt. Now Xtensa target could be builded as EXPERIMENTAL.

[aykevl]

Quickly scanning this patch shows that it still uses the previous license. I think these need to be updated to the new Apache 2.0 license, see any file for the up-to-date file header.

[andreisfr]

Patch is updated according to latest upstream version. Updated licenses.

[andreisfr]

Patch is updated according to latest upstream version.

[andreisfr]

Patch is updated according to LLVM upstream version and latest Xtensa backend version.

[andreisfr]

Patch is updated according to LLVM upstream version.

[saugustine]

This patch is straightforward and correct.

[andreisfr]

Minor changes: corrected comment

[sstefan1]

Hi everyone. Since this has been accepted for some time now, we're planning to commit this on Monday (December 16th). Please let us know if there is anything else we should address.

[andreisfr]

Updated according to latest changes in upstream source code

[MaskRay]

llvm/lib/Target/Xtensa/XtensaTargetMachine.cpp

37

delete blank line. Just return the string.

llvm/lib/Target/Xtensa/XtensaTargetMachine.h

26

Other targets use a static local variable in llvm::get*Target but this seems fine.

29

include llvm/Target/TargetLoweringObjectFile.h for this

44

delete the comment. override self explains.

52

I think all patches use /* footer for header guards, which should all be fixed.

[barannikov88]

llvm/lib/Target/Xtensa/MCTargetDesc/XtensaMCTargetDesc.cpp

14

Global initialization function should use LLVM_EXTERNAL_VISIBILITY.

llvm/lib/Target/Xtensa/TargetInfo/CMakeLists.txt

2

This shouldn't be necessary, these directory are already available for include directives.

llvm/lib/Target/Xtensa/TargetInfo/XtensaTargetInfo.cpp

18

LLVM_EXTERNAL_VISIBILITY

llvm/lib/Target/Xtensa/XtensaTargetMachine.cpp

28

LLVM_EXTERNAL_VISIBILITY

llvm/lib/Target/Xtensa/XtensaTargetMachine.h

24

Appears unused.

26

(Optional) This is gonna be used in multiple files, it might worth moving it ino a header file.

29

This should not be necessary as long as the destructor of XtensaTargetMachine is in *.cpp file. Forward declaration should be enough (and it is already forward declared in TargetMachine.h).

[andreisfr]

Added fixes according to comments

[andreisfr]

llvm/lib/Target/Xtensa/MCTargetDesc/XtensaMCTargetDesc.cpp

14

fixed

llvm/lib/Target/Xtensa/TargetInfo/CMakeLists.txt

2

fixed

llvm/lib/Target/Xtensa/TargetInfo/XtensaTargetInfo.cpp

18

fixed

llvm/lib/Target/Xtensa/XtensaTargetMachine.cpp

28

fixed

37

fixed

llvm/lib/Target/Xtensa/XtensaTargetMachine.h

24

fixed

26

I added "llvm/lib/Target/Xtensa/TargetInfo/XtensaTargetInfo.h" file with "&getTheXtensaTarget();" function, this approach is similar to other backends.

44

fixed

52

fixed

llvm/lib/Target/Xtensa/CMakeLists.txt

+add_llvm_component_group(Xtensa)
+
+add_llvm_target(XtensaCodeGen
+  XtensaTargetMachine.cpp
+
+  LINK_COMPONENTS
+  CodeGen
+  Core
+  Support
+  Target
+  XtensaInfo
+
+  ADD_TO_COMPONENT
+  Xtensa
+  )
+
+add_subdirectory(MCTargetDesc)
+add_subdirectory(TargetInfo)

llvm/lib/Target/Xtensa/MCTargetDesc/CMakeLists.txt

+add_llvm_component_library(LLVMXtensaDesc
+  XtensaMCTargetDesc.cpp
+
+  LINK_COMPONENTS
+  MC
+  Support
+  XtensaInfo
+
+  ADD_TO_COMPONENT
+  Xtensa
+ )

llvm/lib/Target/Xtensa/MCTargetDesc/XtensaMCTargetDesc.h

+//===-- XtensaMCTargetDesc.h - Xtensa Target Descriptions -------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides Xtensa specific target descriptions.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_XTENSA_MCTARGETDESC_XTENSAMCTARGETDESC_H
+#define LLVM_LIB_TARGET_XTENSA_MCTARGETDESC_XTENSAMCTARGETDESC_H
+
+#endif // LLVM_LIB_TARGET_XTENSA_MCTARGETDESC_XTENSAMCTARGETDESC_H

llvm/lib/Target/Xtensa/MCTargetDesc/XtensaMCTargetDesc.cpp

+//===-- XtensaMCTargetDesc.cpp - Xtensa target descriptions ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#include "XtensaMCTargetDesc.h"
+
+// We need to define this function for linking succeed
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeXtensaTargetMC() {}

llvm/lib/Target/Xtensa/TargetInfo/CMakeLists.txt

+add_llvm_component_library(LLVMXtensaInfo
+  XtensaTargetInfo.cpp
+
+  LINK_COMPONENTS
+  MC
+  Support
+
+  ADD_TO_COMPONENT
+  Xtensa
+  )

llvm/lib/Target/Xtensa/TargetInfo/XtensaTargetInfo.h

+//===-- XtensaTargetInfo.h - Xtensa Target Implementation -*- C++ -------*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_XTENSA_TARGETINFO_XTENSATARGETINFO_H
+#define LLVM_LIB_TARGET_XTENSA_TARGETINFO_XTENSATARGETINFO_H
+
+namespace llvm {
+
+class Target;
+
+Target &getTheXtensaTarget();
+
+} // end namespace llvm
+
+#endif // LLVM_LIB_TARGET_XTENSA_TARGETINFO_XTENSATARGETINFO_H

llvm/lib/Target/Xtensa/TargetInfo/XtensaTargetInfo.cpp

+//===-- XtensaTargetInfo.cpp - Xtensa Target Implementation ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "TargetInfo/XtensaTargetInfo.h"
+#include "llvm/MC/TargetRegistry.h"
+using namespace llvm;
+
+Target &llvm::getTheXtensaTarget() {
+  static Target TheXtensaTarget;
+  return TheXtensaTarget;
+}
+
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeXtensaTargetInfo() {
+  RegisterTarget<Triple::xtensa> X(getTheXtensaTarget(), "xtensa", "Xtensa 32",
+                                   "XTENSA");
+}

llvm/lib/Target/Xtensa/XtensaTargetMachine.h

+//===-- XtensaTargetMachine.h - Define TargetMachine for Xtensa -*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the Xtensa specific subclass of TargetMachine.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_XTENSA_XTENSATARGETMACHINE_H
+#define LLVM_LIB_TARGET_XTENSA_XTENSATARGETMACHINE_H
+
+#include "llvm/Target/TargetMachine.h"
+#include <optional>
+
+namespace llvm {
+extern Target TheXtensaTarget;
+
+class XtensaTargetMachine : public LLVMTargetMachine {
+  std::unique_ptr<TargetLoweringObjectFile> TLOF;
+public:
+  XtensaTargetMachine(const Target &T, const Triple &TT, StringRef CPU,
+                      StringRef FS, const TargetOptions &Options,
+                      std::optional<Reloc::Model> RM,
+                      std::optional<CodeModel::Model> CM, CodeGenOpt::Level OL,
+                      bool JIT, bool isLittle);
+
+  XtensaTargetMachine(const Target &T, const Triple &TT, StringRef CPU,
+                      StringRef FS, const TargetOptions &Options,
+                      std::optional<Reloc::Model> RM,
+                      std::optional<CodeModel::Model> CM, CodeGenOpt::Level OL,
+                      bool JIT);
+
+  TargetPassConfig *createPassConfig(PassManagerBase &PM) override;
+  TargetLoweringObjectFile *getObjFileLowering() const override {
+    return TLOF.get();
+  }
+};
+} // end namespace llvm
+
+#endif // LLVM_LIB_TARGET_XTENSA_XTENSATARGETMACHINE_H

llvm/lib/Target/Xtensa/XtensaTargetMachine.cpp

+//===- XtensaTargetMachine.cpp - Define TargetMachine for Xtensa ----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Implements the info about Xtensa target spec.
+//
+//===----------------------------------------------------------------------===//
+
+#include "XtensaTargetMachine.h"
+#include "TargetInfo/XtensaTargetInfo.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
+#include "llvm/CodeGen/TargetPassConfig.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/MC/TargetRegistry.h"
+#include "llvm/Transforms/IPO/PassManagerBuilder.h"
+#include "llvm/Transforms/Scalar.h"
+#include <optional>
+
+using namespace llvm;
+
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeXtensaTarget() {
+  // Register the target.
+  RegisterTargetMachine<XtensaTargetMachine> A(getTheXtensaTarget());
+}
+
+static std::string computeDataLayout(const Triple &TT, StringRef CPU,
+                                     const TargetOptions &Options,
+                                     bool IsLittle) {
+  std::string Ret = "e-m:e-p:32:32-i8:8:32-i16:16:32-i64:64-n32";
+  return Ret;
+}
+
+static Reloc::Model getEffectiveRelocModel(bool JIT,
+                                           std::optional<Reloc::Model> RM) {
+  if (!RM || JIT)
+     return Reloc::Static;
+  return *RM;
+}
+
+XtensaTargetMachine::XtensaTargetMachine(const Target &T, const Triple &TT,
+                                         StringRef CPU, StringRef FS,
+                                         const TargetOptions &Options,
+                                         std::optional<Reloc::Model> RM,
+                                         std::optional<CodeModel::Model> CM,
+                                         CodeGenOpt::Level OL, bool JIT,
+                                         bool IsLittle)
+    : LLVMTargetMachine(T, computeDataLayout(TT, CPU, Options, IsLittle), TT,
+                        CPU, FS, Options, getEffectiveRelocModel(JIT, RM),
+                        getEffectiveCodeModel(CM, CodeModel::Small), OL),
+      TLOF(std::make_unique<TargetLoweringObjectFileELF>()) {
+  initAsmInfo();
+}
+
+XtensaTargetMachine::XtensaTargetMachine(const Target &T, const Triple &TT,
+                                         StringRef CPU, StringRef FS,
+                                         const TargetOptions &Options,
+                                         std::optional<Reloc::Model> RM,
+                                         std::optional<CodeModel::Model> CM,
+                                         CodeGenOpt::Level OL, bool JIT)
+    : XtensaTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL, JIT, true) {}
+
+TargetPassConfig *XtensaTargetMachine::createPassConfig(PassManagerBase &PM) {
+  return new TargetPassConfig(*this, PM);
+}