Spell-check README.markdown

README.markdown

@@ -0,0 +1,202 @@
+# The LLVM m88k backend implementation
+
+This repository contains the current state of my **m88k backend for LLVM**.
+For general information about LLVM, please read [README.md](README.md).
+
+The Motorola 88000 is a RISC architecture developed by Motorola in the late
+1980s. See [Wikipedia](https://en.wikipedia.org/wiki/Motorola_88000) for a
+general overview.
+
+The code is based on the example from my book "Learn LLVM 12" (see
+[O'Reilly](https://learning.oreilly.com/library/view/learn-llvm-12/9781839213502/),
+[Packt](https://www.packtpub.com/product/learn-llvm-12/9781839213502) or
+[Amazon](https://www.amazon.com/Learn-LLVM-12-beginners-libraries/dp/1839213507/)).
+It differs in the following ways:
+- Uses only GlobalISel. SelectionDAG support has been removed.
+- Minimal clang support. Makes it easy to crash the backend.
+- All machine instructions are implemented.
+- Assembler supports `.requires81100` directive.
+- Updates/refactoring of AsmParser, register definition, calling convention, etc.
+- Removed all Itineraries in favor of the new scheduling model.
+
+## Building LLVM with the m88k backend
+
+The m88k backend is added as experimental backend to LLVM, named `M88k`.
+It's defined in the CMake files, but if you want to compile other experimental
+targets, too, then you have to pass option
+
+```-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD="M88k"```
+
+to CMake.
+
+## Development
+
+The main development happens in branch `main-m88k`. The branch
+`release/13.x-m88k` contains an older state based on LLVM 13.x. The branch
+`release/12.x-m88k` contains the source from my
+[book](https://www.packtpub.com/product/learn-llvm-12/9781839213502) on top of
+LLVM 12.x.
+
+This repository mirrors the LLVM `main` and `release/*` branches. I keep my
+files on top of `main`, which means that I often rebase. Sorry!
+
+## Status
+
+The benchmark [MiBench/security-sha](https://github.com/llvm/llvm-test-suite/tree/main/MultiSource/Benchmarks/MiBench/security-sha)
+from the [LLVM test suite](https://github.com/llvm/llvm-test-suite/) can be
+cross-compiled with optimization levels -O0, -O1, and -O2, and gives the same
+result as the native gcc-compiled version. Here is the recipe:
+
+1. Create a directory for the header files. From here I name it `$SYSROOT`.
+2. Copy directory `/usr/include` (with all subdirectories) from your OpenBSD system
+   to your development system into the directory `$SYSROOT/usr/include`.
+3. Change into the LLVM test suite into directory `MultiSource/Benchmarks/MiBench/security-sha`,
+   and compile the test case:
+   `clang -target m88k-openbsd --sysroot=$SYSROOT -c sha*.c`
+4. Copy the object files back to your OpenBSD system.
+5. Link the object files:
+   `gcc -o sha sha*.o`
+6. Run the test case, e.g. `./sha /etc/rc`
+7. To verify the result you can copy the test case source to your OpenBSD system,
+   compile the files with gcc, run the program on the same file and compare the
+   result.
+
+Other test cases and optimization levels may work but there is still a lot to
+implement before significant more test cases function correctly.
+
+## Support
+
+If you like this work, then there are several ways you can support me:
+
+- You can contributes patches.
+- You can provide access to real hardware, e.g. as ssh login.
+- If you find some documentation (e.g. the ABI updates from 88open) I would be
+  happy to receive a copy.
+- You can buy me a beer or a coffee.
+
+## General information about m88k
+
+### Programming manuals
+
+You can find the user manuals for the 88100 and 88110 CPUs, the 88200 MMU and the
+88410 secondary cache controller at bitsavers:
+http://www.bitsavers.org/components/motorola/88000/. The manual for the 88110
+CPU and the 88410 cache controller are also available on GitHub:
+https://github.com/awesome-cpus/awesome-cpus-m88k. Some of the files can also be
+found on https://archive.org/.
+
+The ELF ABI is only available at
+https://archive.org/details/bitsavers_attunixSysa0138776555SystemVRelease488000ABI1990_8011463.
+
+The book [Programming the Motorola 88000](https://www.amazon.com/Programming-Motorola-88000-Michael-Tucker/dp/0830635335/)
+by Michael Tucker and Bruce Coorpender (ISBN-13: 978-0830635337,
+ISBN-10: 0830635335) is out of print.
+
+In the book [Microprocessor Architectures, 2nd Edition](https://www.oreilly.com/library/view/microprocessor-architectures-2nd/9781483295534/)
+by Steve Heath, you find a description of the M88000 architecture in chapter 3.
+
+Regarding the ABI, there were some changes made by the 88open consortium. I have
+not yet found that documents. If you have some of them then please contact me!
+
+### Systems
+
+The [OpenBSD/luna88k](https://www.openbsd.org/luna88k.html) port is still active
+and provides the latest OS releases.
+On a Linux or FreeBSD machine, you can use [GXemul](http://gavare.se/gxemul/) to
+run OpenBSD/luna88k. Alternatively you can use the
+[LUNA emulator nono](http://www.pastel-flower.jp/~isaki/nono/).
+Kenji Aoyama provides a [live image](http://www.nk-home.net/~aoyama/liveimage/)
+which can be used with both emulators.
+
+You can find information about real hardware at [m88k.com](http://m88k.com/).
+
+### Toolchain
+
+gcc 3.3.6 is last version with support for the m88k architecture. See the manual
+page at
+https://gcc.gnu.org/onlinedocs/gcc-3.3.6/gcc/M88K-Options.html#M88K-Options.
+
+You can download that version from
+ftp://ftp.nluug.nl/mirror/languages/gcc/releases/gcc-3.3.6/gcc-3.3.6.tar.gz
+
+binutils 2.16 is last version with support for the m88k architecture. See the
+manual page at
+https://sourceware.org/binutils/docs-2.16/
+
+You can download that version from
+http://ftp.gnu.org/gnu/binutils/binutils-2.16.1a.tar.bz2, and browse the source at
+https://sourceware.org/git/?p=binutils-gdb.git;a=tree;h=a7e286b9ab6d33e8261bfadc992d5bf753b36e9f;hb=a783ed1a1ba08d73583da5a56470e4af5acfb6bd.
+
+### Implementation
+
+The backend is implementated like all other LLVM backends. The main classes
+involved are:
+
+```mermaid
+   classDiagram
+      TargetPassConfig <|-- M88kPassConfig
+      M88kPassConfig .. M88kTargetMachine
+      LLVMTargetMachine <|-- M88kTargetMachine
+      TargetLowering <|-- M88kTargetLowering
+      TargetLoweringObjectFileELF .. M88kTargetMachine
+      M88kGenSubtargetInfo <|-- M88kSubtarget
+      M88kGenInstrInfo <|-- M88kInstrInfo
+      M88kGenRegisterInfo <|-- M88kRegisterInfo
+      M88kTargetMachine --> M88kSubtarget
+      M88kSubtarget o-- M88kInstrInfo
+      M88kSubtarget o-- M88kTargetLowering
+      M88kInstrInfo o-- M88kRegisterInfo
+      class M88kTargetMachine{
+         +getSubtargetImpl() M88kSubtarget
+         +createPassConfig() TargetPassConfig
+         +getObjFileLowering() TargetLoweringObjectFile
+      }
+      class M88kSubtarget{
+         -M88kFrameLowering FrameLowering
+         -M88kInstrInfo InstrInfo
+         +getTargetLowering() M88kTargetLowering
+         +getInstrInfo() M88kInstrInfo
+      }
+      class M88kInstrInfo{
+         -M88kRegisterInfo RI
+         +getRegisterInfo() M88kRegisterInfo
+      }
+      class M88kGenSubtargetInfo{
+         <<Generated>>
+      }
+      class M88kGenInstrInfo{
+         <<Generated>>
+      }
+      class M88kGenRegisterInfo{
+         <<Generated>>
+      }
+```
+
+The `M88kSubtarget` also owns the main passes for GlobalISel:
+
+```mermaid
+   classDiagram
+      M88kSubtarget o-- M88kCallLowering
+      M88kSubtarget o-- M88kM88kLegalizerInfo
+      M88kSubtarget o-- M88kRegisterBankInfo
+      M88kSubtarget o-- M88kInstructionSelector
+      M88kGenSubtargetInfo <|-- M88kSubtarget
+      class M88kSubtarget{
+         -std::unique_ptr~CallLowering~ CallLoweringInfo
+         -std::unique_ptr~LegalizerInfo~ Legalizer
+         -std::unique_ptr~RegisterBankInfo~ RegBankInfo
+         -std::unique_ptr~InstructionSelector~ InstSelector
+         +getCallLowering() CallLowering
+         +getRegBankInfo() RegisterBankInfo
+         +getLegalizerInfo() LegalizerInfo
+         +getInstructionSelector() InstructionSelector
+      }
+      class M88kCallLowering{
+      }
+      class M88kM88kLegalizerInfo{
+      }
+      class M88kRegisterBankInfo{
+      }
+      class M88kInstructionSelector{
+      }
+```

clang/include/clang/Basic/Attr.td

@@ -448,6 +448,7 @@ def TargetMips32 : TargetArch<["mips", "mipsel"]>;
 def TargetAnyMips : TargetArch<["mips", "mipsel", "mips64", "mips64el"]>;
 def TargetMSP430 : TargetArch<["msp430"]>;
 def TargetM68k : TargetArch<["m68k"]>;
+def TargetM88k : TargetArch<["m88k"]>;
 def TargetRISCV : TargetArch<["riscv32", "riscv64"]>;
 def TargetX86 : TargetArch<["x86"]>;
 def TargetAnyX86 : TargetArch<["x86", "x86_64"]>;

clang/include/clang/Basic/BuiltinsM88k.td

@@ -0,0 +1,21 @@
+//===--- BuiltinsM88k.td - M88k Builtin function database ----------------===//
+//
+// 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 "clang/Basic/BuiltinsBase.td"
+
+def FindFirstSet : Builtin {
+  let Spellings = ["__builtin_m88k_ff1"];
+  let Attributes = [NoThrow, Const];
+  let Prototype = "int(unsigned int)";
+}
+
+def FindFirstClear : Builtin {
+  let Spellings = ["__builtin_m88k_ff0"];
+  let Attributes = [NoThrow, Const];
+  let Prototype = "int(unsigned int)";
+}

clang/include/clang/Basic/CMakeLists.txt

@@ -60,6 +60,10 @@ clang_tablegen(BuiltinsRISCV.inc -gen-clang-builtins
   SOURCE BuiltinsRISCV.td
   TARGET ClangBuiltinsRISCV)
 
+  clang_tablegen(BuiltinsM88k.inc -gen-clang-builtins
+  SOURCE BuiltinsM88k.td
+  TARGET ClangBuiltinsM88k)
+
 # ARM NEON and MVE
 clang_tablegen(arm_neon.inc -gen-arm-neon-sema
   SOURCE arm_neon.td

clang/include/clang/Basic/TargetBuiltins.h

@@ -89,6 +89,16 @@ namespace clang {
   };
   }
 
+  /// M88k builtins
+  namespace M88k {
+  enum {
+    LastTIBuiltin = clang::Builtin::FirstTSBuiltin - 1,
+  #define BUILTIN(ID, TYPE, ATTRS) BI##ID,
+  #include "clang/Basic/BuiltinsM88k.inc"
+    LastTSBuiltin
+  };
+  }
+
   /// PPC builtins
   namespace PPC {
     enum {

clang/include/clang/Basic/TargetInfo.h

@@ -355,7 +355,14 @@ class TargetInfo : public TransferrableTargetInfo,
     //    void *__saved_reg_area_end_pointer;
     //    void *__overflow_area_pointer;
     //} va_list;
-    HexagonBuiltinVaList
+    HexagonBuiltinVaList,
+
+    // typedef struct __va_list_tag {
+    //    int __va_arg;
+    //    int *__va_stk;
+    //    int *__va_reg;
+    //} va_list;
+    M88kBuiltinVaList
   };
 
 protected:

clang/include/clang/Driver/Options.td

@@ -215,6 +215,8 @@ def m_hexagon_Features_HVX_Group : OptionGroup<"<hexagon features group>">,
                                    Group<m_Group>, DocName<"Hexagon">;
 def m_m68k_Features_Group: OptionGroup<"<m68k features group>">,
                            Group<m_Group>, DocName<"M68k">;
+def m_m88k_Features_Group: OptionGroup<"<m88k features group>">,
+                           Group<m_Group>, DocName<"M88k">;
 def m_mips_Features_Group : OptionGroup<"<mips features group>">,
                             Group<m_Group>, DocName<"MIPS">;
 def m_ppc_Features_Group : OptionGroup<"<ppc features group>">,
@@ -6021,6 +6023,17 @@ foreach i = {0-7} in
     HelpText<"Reserve the d"#i#" register (M68k only)">;
 } // let Flags = [TargetSpecific]
 
+// M88k features flags
+def m88000 : Flag<["-"], "m88000">, Group<m_m88k_Features_Group>;
+def m88100 : Flag<["-"], "m88100">, Group<m_m88k_Features_Group>;
+def m88110 : Flag<["-"], "m88110">, Group<m_m88k_Features_Group>;
+// TODO This flag is already in the MIPS group.
+//def mcheck_zero_division : Flag<["-"], "mcheck-zero-division">, Group<m_m88k_Features_Group>;
+//def mno_check_zero_division : Flag<["-"], "mno-check-zero-division">, Group<m_m88k_Features_Group>;
+def muse_div_instruction : Flag<["-"], "muse-div-instruction">,
+  Group<m_m88k_Features_Group>,
+  HelpText<"Use div instruction for signed integer division (MC88100 only)">;
+
 // X86 feature flags
 let Flags = [TargetSpecific] in {
 def mx87 : Flag<["-"], "mx87">, Group<m_x86_Features_Group>;

clang/lib/AST/ASTContext.cpp

@@ -9192,6 +9192,47 @@ static TypedefDecl *CreateHexagonBuiltinVaListDecl(const ASTContext *Context) {
   return Context->buildImplicitTypedef(VaListTagArrayType, "__builtin_va_list");
 }
 
+static TypedefDecl *CreateM88kBuiltinVaListDecl(const ASTContext *Context) {
+  // typedef struct __va_list_tag {
+  RecordDecl *VaListTagDecl;
+  VaListTagDecl = Context->buildImplicitRecord("__va_list_tag");
+  VaListTagDecl->startDefinition();
+
+  const size_t NumFields = 3;
+  QualType FieldTypes[NumFields];
+  const char *FieldNames[NumFields];
+
+  //   int __va_arg;
+  FieldTypes[0] = Context->IntTy;
+  FieldNames[0] = "__va_arg";
+
+  //   int *__va_stk;
+  FieldTypes[1] = Context->getPointerType(Context->IntTy);
+  FieldNames[1] = "__va_stk";
+
+  //   int *__va_reg;
+  FieldTypes[2] = Context->getPointerType(Context->IntTy);
+  FieldNames[2] = "__va_reg";
+
+  // Create fields
+  for (unsigned i = 0; i < NumFields; ++i) {
+    FieldDecl *Field = FieldDecl::Create(
+        const_cast<ASTContext &>(*Context), VaListTagDecl, SourceLocation(),
+        SourceLocation(), &Context->Idents.get(FieldNames[i]), FieldTypes[i],
+        /*TInfo=*/0,
+        /*BitWidth=*/0,
+        /*Mutable=*/false, ICIS_NoInit);
+    Field->setAccess(AS_public);
+    VaListTagDecl->addDecl(Field);
+  }
+  VaListTagDecl->completeDefinition();
+  Context->VaListTagDecl = VaListTagDecl;
+  QualType VaListTagType = Context->getRecordType(VaListTagDecl);
+
+  // } __builtin_va_list;
+  return Context->buildImplicitTypedef(VaListTagType, "__builtin_va_list");
+}
+
 static TypedefDecl *CreateVaListDecl(const ASTContext *Context,
                                      TargetInfo::BuiltinVaListKind Kind) {
   switch (Kind) {
@@ -9213,6 +9254,8 @@ static TypedefDecl *CreateVaListDecl(const ASTContext *Context,
     return CreateSystemZBuiltinVaListDecl(Context);
   case TargetInfo::HexagonBuiltinVaList:
     return CreateHexagonBuiltinVaListDecl(Context);
+  case TargetInfo::M88kBuiltinVaList:
+    return CreateM88kBuiltinVaListDecl(Context);
   }
 
   llvm_unreachable("Unhandled __builtin_va_list type kind");

clang/lib/Basic/CMakeLists.txt

@@ -104,6 +104,7 @@ add_clang_library(clangBasic
   Targets/Le64.cpp
   Targets/LoongArch.cpp
   Targets/M68k.cpp
+  Targets/M88k.cpp
   Targets/MSP430.cpp
   Targets/Mips.cpp
   Targets/NVPTX.cpp

clang/lib/Basic/Targets.cpp

@@ -26,6 +26,7 @@
 #include "Targets/Le64.h"
 #include "Targets/LoongArch.h"
 #include "Targets/M68k.h"
+#include "Targets/M88k.h"
 #include "Targets/MSP430.h"
 #include "Targets/Mips.h"
 #include "Targets/NVPTX.h"
@@ -344,6 +345,16 @@ std::unique_ptr<TargetInfo> AllocateTarget(const llvm::Triple &Triple,
       return std::make_unique<M68kTargetInfo>(Triple, Opts);
     }
 
+  case llvm::Triple::m88k:
+    switch (os) {
+    case llvm::Triple::OpenBSD:
+      return std::make_unique<OpenBSDTargetInfo<M88kTargetInfo>>(Triple, Opts);
+    case llvm::Triple::SYSV4:
+      return std::make_unique<SYSVTargetInfo<M88kTargetInfo>>(Triple, Opts);
+    default:
+      return std::make_unique<M88kTargetInfo>(Triple, Opts);
+    }
+
   case llvm::Triple::le32:
     switch (os) {
     case llvm::Triple::NaCl: