feat: initial support

.gitignore

@@ -1,4 +1,7 @@
+.cache/
+.vscode/
 .direnv/
+build/
 .pre-commit-config.yaml
 
 # Created by https://www.toptal.com/developers/gitignore/api/c++,c,cmake
@@ -95,3 +98,41 @@ _deps
 *-prefix/
 
 # End of https://www.toptal.com/developers/gitignore/api/c++,c,cmake
+# Created by https://www.toptal.com/developers/gitignore/api/c++
+# Edit at https://www.toptal.com/developers/gitignore?templates=c++
+
+### C++ ###
+# Prerequisites
+*.d
+
+# Compiled Object files
+*.slo
+*.lo
+*.o
+*.obj
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Compiled Dynamic libraries
+*.so
+*.dylib
+*.dll
+
+# Fortran module files
+*.mod
+*.smod
+
+# Compiled Static libraries
+*.lai
+*.la
+*.a
+*.lib
+
+# Executables
+*.exe
+*.out
+*.app
+
+# End of https://www.toptal.com/developers/gitignore/api/c++

CMakeLists.txt

@@ -6,4 +6,3 @@ set(CMAKE_C_STANDARD 17)
 
 include_directories(include)
 add_subdirectory(src)
-

flake.lock

@@ -105,6 +105,26 @@
         "type": "github"
       }
     },
+    "nur-xin": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1714033851,
+        "narHash": "sha256-Mi7m3p9vmtNOdyD1hLse/tzxDuV3bwP0gKrmOBPiQ4c=",
+        "ref": "refs/heads/master",
+        "rev": "809554f41ac44acc4b1ec21473746c2af9993f2f",
+        "revCount": 149,
+        "type": "git",
+        "url": "https://git.xinyang.life/xin/nur.git"
+      },
+      "original": {
+        "type": "git",
+        "url": "https://git.xinyang.life/xin/nur.git"
+      }
+    },
     "pre-commit-hooks": {
       "inputs": {
         "flake-compat": "flake-compat",
@@ -133,6 +153,7 @@
       "inputs": {
         "flake-utils": "flake-utils",
         "nixpkgs": "nixpkgs",
+        "nur-xin": "nur-xin",
         "pre-commit-hooks": "pre-commit-hooks"
       }
     },

flake.nix

@@ -2,6 +2,10 @@
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
     flake-utils.url = "github:numtide/flake-utils";
+    nur-xin = {
+      url = "git+https://git.xinyang.life/xin/nur.git";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
     pre-commit-hooks = {
       url = "github:cachix/pre-commit-hooks.nix";
       inputs.nixpkgs.follows = "nixpkgs";
@@ -11,7 +15,13 @@
   outputs = { self, ... }@inputs: with inputs;
     flake-utils.lib.eachDefaultSystem (system:
       let
-        pkgs = import nixpkgs { inherit system; };
+        pkgs = import nixpkgs {
+          inherit system; overlays = [
+          (self: super: {
+            mini-gdbstub = nur-xin.legacyPackages.${system}.mini-gdbstub;
+          })
+        ];
+        };
       in
       {
         checks = {
@@ -35,6 +45,8 @@
             clang-tools
             cmake
             gdb
+            cli11
+            mini-gdbstub
           ];
         };
       }

include/api.h

@@ -1,35 +0,0 @@
-#ifndef _DIFFTEST_API_H_
-#define _DIFFTEST_API_H_
-
-#include <cstddef>
-
-extern "C" {
-
-typedef struct {
-  enum {
-    ACT_NONE,
-    ACT_BREAKPOINT,
-    ACT_WATCH,
-    ACT_RWATCH,
-    ACT_WWATCH,
-    ACT_SHUTDOWN
-  } reason;
-  size_t data;
-} gdb_action_t;
-
-typedef enum { BP_SOFTWARE = 0, BP_WRITE, BP_READ, BP_ACCESS } bp_type_t;
-
-struct target_ops {
-  void (*cont)(void *args, gdb_action_t *res);
-  void (*stepi)(void *args, gdb_action_t *res);
-  int (*read_reg)(void *args, int regno, size_t *value);
-  int (*write_reg)(void *args, int regno, size_t value);
-  int (*read_mem)(void *args, size_t addr, size_t len, void *val);
-  int (*write_mem)(void *args, size_t addr, size_t len, void *val);
-  bool (*set_bp)(void *args, size_t addr, bp_type_t type);
-  bool (*del_bp)(void *args, size_t addr, bp_type_t type);
-  void (*on_interrupt)(void *args);
-};
-}
-
-#endif

include/api.hpp

@@ -0,0 +1,68 @@
+#ifndef _DIFFTEST_API_H_
+#define _DIFFTEST_API_H_
+
+#include <cstddef>
+#include <filesystem>
+#include <gdbstub.h>
+#include <string>
+#include <vector>
+
+// Target dynamic library has to implement these functions
+struct TargetOps {
+  typedef void (*cont_t)(void *args, gdb_action_t *res);
+  cont_t cont;
+
+  typedef void (*stepi_t)(void *args, gdb_action_t *res);
+  stepi_t stepi;
+
+  typedef int (*read_reg_t)(void *args, int regno, size_t *value);
+  read_reg_t read_reg;
+
+  typedef int (*write_reg_t)(void *args, int regno, size_t value);
+  write_reg_t write_reg;
+
+  typedef int (*read_mem_t)(void *args, size_t addr, size_t len, void *val);
+  read_mem_t read_mem;
+
+  typedef int (*write_mem_t)(void *args, size_t addr, size_t len, void *val);
+  write_mem_t write_mem;
+
+  typedef bool (*set_bp_t)(void *args, size_t addr, bp_type_t type);
+  set_bp_t set_bp;
+
+  typedef bool (*del_bp_t)(void *args, size_t addr, bp_type_t type);
+  del_bp_t del_bp;
+
+  typedef void (*on_interrupt_t)(void *args);
+  on_interrupt_t on_interrupt;
+
+  typedef void (*init_t)(void *args);
+  init_t init;
+};
+
+struct TargetMeta {
+  std::string name;
+  std::filesystem::path libpath;
+  void *dlhandle;
+};
+
+class Target {
+public:
+  TargetOps ops;
+  TargetMeta meta;
+  arch_info_t arch;
+  size_t argsize;
+  std::vector<uint8_t> args; // used as a buffer to store target specific values
+
+  gdb_action_t last_res;
+
+  Target(){};
+  Target(const std::string &name, const std::string &prefix,
+         const std::filesystem::path &path);
+  ~Target();
+
+  bool is_on_breakpoint() const;
+  bool is_on_breakpoint(const gdb_action_t &res) const;
+};
+
+#endif

include/config.hpp

@@ -0,0 +1,14 @@
+#include <CLI/App.hpp>
+#include <CLI/CLI.hpp>
+#include <CLI/Validators.hpp>
+#include <filesystem>
+#include <vector>
+
+struct Config {
+  std::filesystem::path memory_file;
+  std::vector<std::filesystem::path> refs;
+  std::filesystem::path dut;
+  int cli_parse(int argc, char **argv);
+};
+
+extern Config config;

include/difftest.hpp

@@ -1,4 +1,73 @@
 #ifndef _DIFFTEST_DIFFTEST_H_
 #define _DIFFTEST_DIFFTEST_H_
+#include "api.hpp"
+#include <filesystem>
+#include <gdbstub.h>
+#include <stdexcept>
+#include <vector>
+
+#include <iostream>
+class Difftest {
+private:
+  Target dut;
+  std::vector<Target> refs;
+
+public:
+  Difftest(Target &&dut, std::vector<Target> &&refs);
+
+  void setup(const std::filesystem::path &memory_file);
+  gdb_action_t stepi();
+  gdb_action_t cont();
+  static bool check(Target &dut, Target &ref) {
+    for (int r = 0; r < dut.arch.reg_num; r++) {
+      size_t regdut = 0, regref = 0;
+      dut.ops.read_reg(dut.args.data(), r, &regdut);
+      ref.ops.read_reg(ref.args.data(), r, &regref);
+      if (regdut != regref) {
+        std::cout << "reg: " << r << " dut: " << regdut << " ref: " << regref
+                  << std::endl;
+        throw std::runtime_error("Difftest failed");
+      }
+    }
+    return true;
+  };
+  bool check_all();
+
+  class Iterator {
+  private:
+    Difftest &difftest;
+    size_t index;
+    bool on_dut;
+
+  public:
+    Iterator(Difftest &difftest, size_t index, bool on_dut)
+        : difftest(difftest), index(index), on_dut(on_dut) {}
+
+    Iterator &operator++() {
+      if (on_dut) {
+        on_dut = false;
+      } else {
+        ++index;
+      }
+      return *this;
+    }
+
+    bool operator!=(const Iterator &other) const {
+      return index != other.index || on_dut != other.on_dut;
+    }
+
+    Target &operator*() {
+      if (on_dut) {
+        return difftest.dut;
+      } else {
+        return difftest.refs.at(index);
+      }
+    }
+  };
+
+  Iterator begin() { return Iterator(*this, 0, true); }
+
+  Iterator end() { return Iterator(*this, refs.size(), false); }
+};
 
 #endif

src/CMakeLists.txt

@@ -1,2 +1,3 @@
-add_executable(test main.cpp)
-
+add_executable(diffu cli.cpp difftest.cpp loader.cpp main.cpp)
+target_link_libraries(diffu PRIVATE gdbstub)
+set_target_properties(diffu PROPERTIES ENABLE_EXPORTS 1)

src/cli.cpp

@@ -0,0 +1,25 @@
+#include "config.hpp"
+#include <CLI/App.hpp>
+#include <CLI/Validators.hpp>
+
+int Config::cli_parse(int argc, char **argv) {
+  CLI::App app;
+  app.add_option("-m,--memory", memory_file, "Content of memory")
+      ->required()
+      ->check(CLI::ExistingFile);
+
+  app.add_option("--ref", refs, "Reference dynamic library")
+      ->required()
+      ->check(CLI::ExistingFile);
+
+  app.add_option("--dut", dut, "Design under test")
+      ->required()
+      ->check(CLI::ExistingFile);
+
+  app.set_config("-c,--config")
+      ->transform(CLI::FileOnDefaultPath("./difftest.toml"));
+
+  CLI11_PARSE(app, argc, argv);
+
+  return 0;
+}

src/difftest.cpp

@@ -0,0 +1,98 @@
+#include "api.hpp"
+#include <difftest.hpp>
+#include <fstream>
+#include <stdexcept>
+
+#include <cstdio>
+
+Difftest::Difftest(Target &&dut, std::vector<Target> &&refs) {
+  this->dut = std::move(dut);
+  this->refs = std::move(refs);
+
+  for (const auto &ref : refs) {
+    if (dut.arch.reg_byte != ref.arch.reg_byte ||
+        dut.arch.reg_num != ref.arch.reg_num) {
+      throw std::runtime_error("Ref and dut must have the same architecture");
+    }
+  }
+}
+
+void Difftest::setup(const std::filesystem::path &memory_file) {
+  std::ifstream is = std::ifstream(memory_file, std::ios::binary);
+
+  // Seek to the end to determine the file size
+  is.seekg(0, std::ios::end);
+  std::streampos memsize = is.tellg();
+  is.seekg(0, std::ios::beg);
+
+  std::vector<char> membuf(memsize);
+  is.read(membuf.data(), memsize);
+  is.close();
+
+  // Initialize memory
+  // TODO: reset vector should not be hardcoded
+  // for(auto target : *this) {
+  for (auto it = this->begin(); it != this->end(); ++it) {
+    auto &target = *it;
+    printf("init addr: %p\n", target.ops.init);
+    target.ops.init(target.args.data());
+    target.ops.write_mem(target.args.data(), 0x80000000UL, membuf.size(),
+                         membuf.data());
+    target.ops.write_reg(target.args.data(), 32, 0x80000000UL);
+  }
+}
+
+bool Difftest::check_all() {
+  for (auto &ref : refs) {
+    check(dut, ref);
+  }
+  return true;
+}
+
+gdb_action_t Difftest::stepi() {
+  bool breakflag = false;
+  Target *pbreak;
+  for (auto it = this->begin(); it != this->end(); ++it) {
+    auto &target = *it;
+    target.ops.stepi(target.args.data(), &target.last_res);
+    if (target.is_on_breakpoint()) {
+      breakflag = true;
+      pbreak = &target;
+    }
+  }
+
+  if (breakflag) {
+    gdb_action_t ret = {.reason = gdb_action_t::ACT_BREAKPOINT};
+    pbreak->ops.read_reg(pbreak->args.data(), 32, &ret.data);
+    return ret;
+  }
+  return {gdb_action_t::ACT_NONE, 0};
+}
+
+gdb_action_t Difftest::cont() {
+  bool breakflag = false;
+  Target *pbreak;
+  check_all();
+  std::cerr << "setup finished." << std::endl;
+  while (true) {
+    // for(auto &target : *this) {
+    for (auto it = this->begin(); it != this->end(); ++it) {
+      auto &target = *it;
+      target.ops.stepi(target.args.data(), &target.last_res);
+
+      if (target.is_on_breakpoint()) {
+        breakflag = true;
+        pbreak = &target;
+      }
+    }
+
+    check_all();
+
+    if (breakflag) {
+      gdb_action_t ret = {.reason = gdb_action_t::ACT_BREAKPOINT};
+      pbreak->ops.read_reg(pbreak->args.data(), 32, &ret.data);
+      return ret;
+    }
+  }
+  return {gdb_action_t::ACT_NONE, 0};
+}

src/loader.cpp

@@ -0,0 +1,76 @@
+#include "api.hpp"
+#include <cstdint>
+#include <dlfcn.h>
+#include <iostream>
+#include <stdexcept>
+
+Target::Target(const std::string &name, const std::string &func_prefix,
+               const std::filesystem::path &path) {
+
+  std::cout << path.c_str() << std::endl;
+  meta = {.name = name,
+          .libpath = path,
+          .dlhandle = dlopen(path.c_str(), RTLD_LAZY)};
+
+  if (!meta.dlhandle) {
+    throw std::runtime_error(dlerror());
+  }
+
+#define LOAD_SYMBOL(ops, handle, prefix, name)                                 \
+  do {                                                                         \
+    ops.name = reinterpret_cast<decltype(TargetOps::name)>(                    \
+        dlsym(handle, (prefix + #name).c_str()));                              \
+    if (!ops.name)                                                             \
+      goto load_error;                                                         \
+  } while (0);
+
+  LOAD_SYMBOL(ops, meta.dlhandle, func_prefix, cont);
+  LOAD_SYMBOL(ops, meta.dlhandle, func_prefix, stepi);
+  LOAD_SYMBOL(ops, meta.dlhandle, func_prefix, read_reg);
+  LOAD_SYMBOL(ops, meta.dlhandle, func_prefix, write_reg);
+  LOAD_SYMBOL(ops, meta.dlhandle, func_prefix, read_mem);
+  LOAD_SYMBOL(ops, meta.dlhandle, func_prefix, write_mem);
+  LOAD_SYMBOL(ops, meta.dlhandle, func_prefix, set_bp);
+  LOAD_SYMBOL(ops, meta.dlhandle, func_prefix, del_bp);
+  LOAD_SYMBOL(ops, meta.dlhandle, func_prefix, on_interrupt);
+  LOAD_SYMBOL(ops, meta.dlhandle, func_prefix, init);
+
+#undef LOAD_SYMBOL
+
+  size_t *argsize_sym;
+  argsize_sym = reinterpret_cast<size_t *>(dlsym(meta.dlhandle, "argsize"));
+  if (!argsize_sym)
+    goto load_error;
+
+  argsize = *argsize_sym;
+  args = std::vector<uint8_t>(argsize);
+
+  arch_info_t *arch_sym;
+  arch_sym =
+      reinterpret_cast<arch_info_t *>(dlsym(meta.dlhandle, "isa_arch_info"));
+  if (!arch_sym)
+    goto load_error;
+  return;
+
+load_error:
+  std::string err = std::string(dlerror());
+  dlclose(meta.dlhandle);
+  throw std::runtime_error(err);
+}
+
+Target::~Target() {
+  std::cout << "Destruct target " << meta.name << std::endl;
+  dlclose(meta.dlhandle);
+}
+
+bool Target::is_on_breakpoint() const { return is_on_breakpoint(last_res); }
+
+bool Target::is_on_breakpoint(const gdb_action_t &res) const {
+  if (res.reason == gdb_action_t::ACT_BREAKPOINT ||
+      res.reason == gdb_action_t::ACT_RWATCH ||
+      res.reason == gdb_action_t::ACT_WATCH ||
+      res.reason == gdb_action_t::ACT_WWATCH) {
+    return true;
+  }
+  return false;
+}

src/main.cpp

@@ -1,5 +1,23 @@
-#include <difftest.hpp>
+#include "api.hpp"
+#include "config.hpp"
+#include "difftest.hpp"
 
-using reg_t = uint32_t;
+int main(int argc, char **argv) {
+  Config config;
+  int ret = 0;
+  ret = config.cli_parse(argc, argv);
+  if (ret)
+    return ret;
 
-int main() { return 0; }
+  std::vector<Target> refs;
+  Target dut = Target{"dut", "nemu_", config.dut};
+  for (const auto &ref_libpath : config.refs) {
+    refs.emplace_back(ref_libpath.string(), "nemu_", ref_libpath);
+  }
+
+  Difftest difftest{std::move(dut), std::move(refs)};
+  difftest.setup(config.memory_file);
+  difftest.cont();
+
+  return 0;
+}