11 files changed, 451 insertions, 0 deletions
diff --git a/willow/tools/willowc/BUILD.bazel b/willow/tools/willowc/BUILD.bazel
index e69de29..708de13 100644
--- a/willow/tools/willowc/BUILD.bazel
+++ b/willow/tools/willowc/BUILD.bazel
@@ -0,0 +1,27 @@
+load("@rules_cc//cc:defs.bzl", "cc_library", "cc_binary")
+
+cc_library(
+    name = "willowc_lib",
+    srcs = glob([
+        "lib/*.cpp",
+    ]),
+    hdrs = glob([
+        "include/*.hpp",
+    ]),
+    copts = [
+        "-std=c++23",
+        "-Wall",
+    ],
+    deps = ["//willow"],
+    strip_include_prefix = "include",
+    visibility = ["//visibility:public"],
+)
+
+cc_binary(
+    name = "willowc",
+    srcs = [
+        "main.cpp",
+    ],
+    deps = [":willowc_lib"],
+    visibility = ["//visibility:public"],
+)
diff --git a/willow/tools/willowc/include/ast.hpp b/willow/tools/willowc/include/ast.hpp
new file mode 100644
index 0000000..8c59067
--- /dev/null
+++ b/willow/tools/willowc/include/ast.hpp
@@ -0,0 +1,62 @@
+#ifndef WILLOWC_INCLUDE_AST_HPP
+#define WILLOWC_INCLUDE_AST_HPP
+
+#include <cstdint>
+#include <memory>
+#include <vector>
+
+#include <willow/IR/Instructions.h>
+#include <willow/IR/Types.h>
+
+#include <tokenizer.hpp>
+
+namespace willowc {
+
+using Opcode = willow::Instruction::Opcode;
+using TokenIndex = std::size_t;
+
+// this is like willow::ValueKind, but treats groups all ssa values into 'Value'
+// (because they can't be differentiated by syntax alone)
+enum class ExprKind { Constant, BasicBlock, Function, Value };
+
+struct ExprAST {
+  ExprKind kind;
+
+  std::string name;
+  // token??
+};
+
+struct InstAST {
+  Opcode op;
+  std::string name;
+
+  std::vector<std::unique_ptr<ExprAST>> args;
+};
+
+struct BlockAST {
+  std::string label;
+  std::vector<std::unique_ptr<InstAST>> body;
+};
+
+struct ParameterAST {
+  std::string name;
+  willow::Type type;
+};
+
+struct FunctionDeclAST {
+  std::string name;
+  std::vector<std::unique_ptr<ParameterAST>> parameters;
+  std::string returntype;
+
+  std::vector<std::unique_ptr<BlockAST>> body;
+  // TODO: movable symbol table
+};
+
+struct ModuleAST {
+  std::vector<std::unique_ptr<FunctionDeclAST>> Functions;
+  // TODO: imports, symbol table
+};
+
+}; // namespace willowc
+
+#endif // WILLOWC_INCLUDE_AST_HPP
diff --git a/willow/tools/willowc/include/expr.hpp b/willow/tools/willowc/include/expr.hpp
new file mode 100644
index 0000000..15d2985
--- /dev/null
+++ b/willow/tools/willowc/include/expr.hpp
@@ -0,0 +1,4 @@
+#ifndef WILLOWC_INCLUDE_EXPR_HPP
+#define WILLOWC_INCLUDE_EXPR_HPP
+
+#endif // WILLOWC_INCLUDE_EXPR_HPP
diff --git a/willow/tools/willowc/include/parser.hpp b/willow/tools/willowc/include/parser.hpp
new file mode 100644
index 0000000..825dfdd
--- /dev/null
+++ b/willow/tools/willowc/include/parser.hpp
@@ -0,0 +1,33 @@
+#ifndef WILLOWC_INCLUDE_PARSER_HPP
+#define WILLOWC_INCLUDE_PARSER_HPP
+
+#include <tokenizer.hpp>
+#include <ast.hpp>
+
+#include <optional>
+#include <memory>
+#include <vector>
+
+namespace willowc {
+
+class Parser {
+  std::string_view buf;
+
+  std::vector<TokenKind> kinds;
+  std::vector<std::size_t> starts;
+  Tokenizer tokenizer;
+
+  std::size_t pos;
+
+public:
+  Parser(std::string_view buf) : buf(buf), tokenizer(buf) {}
+
+  std::optional<std::unique_ptr<ModuleAST>> parse();
+
+  TokenKind kind() const { return kinds[pos]; }
+  std::size_t start() const { return starts[pos]; }
+};
+
+} // namespace willowc
+
+#endif // WILLOWC_INCLUDE_PARSER_HPP
diff --git a/willow/tools/willowc/include/sourcemanager.hpp b/willow/tools/willowc/include/sourcemanager.hpp
new file mode 100644
index 0000000..a526e48
--- /dev/null
+++ b/willow/tools/willowc/include/sourcemanager.hpp
@@ -0,0 +1,26 @@
+#ifndef WILLOWC_INCLUDE_SOURCEMANAGER_HPP
+#define WILLOWC_INCLUDE_SOURCEMANAGER_HPP
+
+#include <filesystem>
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace willowc {
+
+using FileID = std::uint32_t;
+
+class SourceManager {
+struct File {
+  std::string path;
+  std::unique_ptr<char[]> buf;
+};
+public:
+  std::optional<FileID> addFile(std::string_view path);
+private:
+  std::vector<File> file_table;
+};
+
+} // namespace willowc
+
+#endif // WILLOWC_INCLUDE_SOURCEMANAGER_HPP
diff --git a/willow/tools/willowc/include/tokenizer.hpp b/willow/tools/willowc/include/tokenizer.hpp
new file mode 100644
index 0000000..3de9d32
--- /dev/null
+++ b/willow/tools/willowc/include/tokenizer.hpp
@@ -0,0 +1,72 @@
+#ifndef WILLOWC_INCLUDE_TOKENIZER_HPP
+#define WILLOWC_INCLUDE_TOKENIZER_HPP
+
+#include <willow/IR/Location.h>
+
+namespace willowc {
+
+enum class TokenKind {
+  Function,
+  Variable,
+  Constant,
+  Type,
+  Label,
+  Inst,
+
+  Comma,
+  Semicolon,
+  LParen,
+  RParen,
+  LCurly,
+  RCurly,
+  Equals,
+  RArrow,
+  Comment,
+
+  FuncKW,
+  Eof,
+  Invalid,
+};
+
+struct Token {
+  std::size_t start, end;
+  TokenKind kind;
+};
+
+class Tokenizer {
+  std::string_view buf;
+  std::size_t offset;
+
+  void skip(std::size_t idx = 1) { offset += idx; }
+
+  char eat(std::size_t num = 1) {
+    if (offset >= buf.length())
+      return '\0';
+
+    char c = buf[offset];
+    offset += num;
+    return c;
+  }
+
+  char peek(std::size_t idx = 0) {
+    if (offset + idx >= buf.length())
+      return '\0';
+
+    return buf[offset + idx];
+  }
+
+  bool scan_id(bool accept_digits);
+  bool scan_dec();
+  bool scan_hex();
+  bool scan_constant();
+public:
+  explicit Tokenizer(std::string_view buf, std::size_t offset = 0)
+      : buf{buf}, offset{offset} {}
+
+  Token scan();
+  void seek(uint64_t offset);
+};
+
+} // namespace willowc
+
+#endif // WILLOWC_INCLUDE_TOKENIZER_HPP
diff --git a/willow/tools/willowc/lib/driver.cpp b/willow/tools/willowc/lib/driver.cpp
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/willow/tools/willowc/lib/driver.cpp
diff --git a/willow/tools/willowc/lib/parser.cpp b/willow/tools/willowc/lib/parser.cpp
new file mode 100644
index 0000000..becc171
--- /dev/null
+++ b/willow/tools/willowc/lib/parser.cpp
@@ -0,0 +1,9 @@
+#include <parser.hpp>
+
+namespace willowc {
+
+std::optional<std::unique_ptr<ModuleAST>> parse() {
+
+}
+
+}
diff --git a/willow/tools/willowc/lib/sourcemanager.cpp b/willow/tools/willowc/lib/sourcemanager.cpp
new file mode 100644
index 0000000..e2a8e72
--- /dev/null
+++ b/willow/tools/willowc/lib/sourcemanager.cpp
@@ -0,0 +1,41 @@
+#include <filesystem>
+
+#include <fstream>
+#include <sourcemanager.hpp>
+
+namespace willowc {
+
+std::optional<FileID> SourceManager::addFile(std::string_view _path) {
+  std::error_code ec;
+
+  std::filesystem::path uncanonical_path{_path};
+  auto path = std::filesystem::weakly_canonical(uncanonical_path, ec);
+  if (ec) {
+    return false;
+  }
+  std::string display_path = path.make_preferred();
+
+  if (!std::filesystem::exists(path, ec) || ec)
+    return std::nullopt;
+
+  if (!std::filesystem::is_regular_file(path, ec) || ec)
+    return std::nullopt;
+
+  std::size_t filesize = std::filesystem::file_size(path, ec);
+  if (ec)
+    return std::nullopt;
+
+  std::ifstream f{display_path, std::ios::binary};
+  if (!f)
+    return std::nullopt;
+
+  auto buf = std::make_unique<char[]>(filesize);
+  f.read(buf.get(), filesize);
+
+  const FileID id = file_table.size();
+  file_table.push_back(File{std::move(display_path), std::move(buf)});
+
+  return id;
+}
+
+} // namespace willowc
diff --git a/willow/tools/willowc/lib/tokenizer.cpp b/willow/tools/willowc/lib/tokenizer.cpp
new file mode 100644
index 0000000..0c1f917
--- /dev/null
+++ b/willow/tools/willowc/lib/tokenizer.cpp
@@ -0,0 +1,176 @@
+#include <tokenizer.hpp>
+
+namespace willowc {
+
+static inline bool is_space(unsigned char c) {
+  return c == ' ' || c == '\t' || c == '\n' || c == '\r';
+}
+static inline bool is_digit(unsigned char c) { return c >= '0' && c <= '9'; }
+static inline bool is_xdigit(unsigned char c) {
+  return is_digit(c) || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F');
+}
+static inline bool is_alpha(unsigned char c) {
+  unsigned char x = static_cast<unsigned char>(c | 0x20);
+  return x >= 'a' && x <= 'z';
+}
+
+static inline bool valid_id_start(int c) {
+  return is_alpha(c) || c == '$' || c == '.' || c == '_' || c == '-';
+}
+
+bool Tokenizer::scan_id(bool accept_digits = true) {
+  char c = peek();
+
+  if (accept_digits && is_digit(c)) {
+    // if it starts with a digit, must be all digits
+    while (is_digit(peek()))
+      skip();
+    return true;
+  }
+
+  if (!valid_id_start(c))
+    return false;
+
+  while (valid_id_start(peek()) || isdigit(peek()))
+    skip();
+
+  return true;
+}
+
+Token Tokenizer::scan() {
+  std::size_t start = this->offset;
+
+  while (isspace(peek()))
+    skip();
+
+  TokenKind k = [&] {
+    switch (peek()) {
+    case '@':
+      skip();
+      if (scan_id(false))
+        return TokenKind::Function;
+      return TokenKind::Invalid;
+    case '%':
+      skip();
+      if (scan_id())
+        return TokenKind::Variable;
+      return TokenKind::Invalid;
+    case '^':
+      skip();
+      if (scan_id())
+        return TokenKind::Label;
+      return TokenKind::Invalid;
+    case ',':
+      skip();
+      return TokenKind::Comma;
+    case ';':
+      skip();
+      return TokenKind::Semicolon;
+    case '(':
+      skip();
+      return TokenKind::LParen;
+    case ')':
+      skip();
+      return TokenKind::RParen;
+    case '{':
+      skip();
+      return TokenKind::LCurly;
+    case '}':
+      skip();
+      return TokenKind::RCurly;
+    case '=':
+      skip();
+      return TokenKind::Equals;
+    case '-': {
+      if (peek(1) == '>') {
+        skip(2);
+        return TokenKind::RArrow;
+      }
+      if (isdigit(peek(1))) {
+        skip();
+        if (scan_dec())
+          return TokenKind::Constant;
+      }
+      return TokenKind::Invalid;
+    }
+    case '/': {
+      skip();
+      if (peek() != '/')
+        return TokenKind::Invalid;
+
+      skip();
+      char c = eat();
+      while (c != '\0' && c != '\n')
+        c = eat();
+
+      return TokenKind::Comment;
+    }
+    case '\0':
+      return TokenKind::Eof;
+    default: {
+      if (is_digit(peek()))
+        return scan_constant() ? TokenKind::Constant : TokenKind::Invalid;
+
+      if (peek() == 'i') {
+        skip();
+        if (scan_dec())
+          return TokenKind::Type;
+      }
+
+      if (isalpha(peek())) {
+        skip();
+        while (isalnum(peek()) || peek() == '.')
+          skip();
+        return TokenKind::Inst;
+      }
+
+      return TokenKind::Invalid;
+    }
+    }
+  }();
+
+  return Token{start, offset, k};
+}
+
+bool Tokenizer::scan_dec() {
+  if (!is_digit(peek()))
+    return false;
+  skip();
+  while (is_digit(peek()))
+    skip();
+
+  return true;
+}
+
+bool Tokenizer::scan_hex() {
+  if (!is_xdigit(peek()))
+    return false;
+  skip();
+  while (is_xdigit(peek()))
+    skip();
+
+  return true;
+}
+
+bool Tokenizer::scan_constant() {
+  if (peek() == '-')
+    skip();
+
+  if (peek() == '0') {
+    skip();
+    if (is_digit(peek()))
+      return false;
+    if (peek() == 'x') {
+      skip();
+      return scan_hex();
+    } else {
+      return true; // 0
+    }
+  } else if (is_digit(peek())) {
+    return scan_dec();
+  }
+
+  return false;
+}
+
+} // namespace willowc
diff --git a/willow/tools/willowc/main.cpp b/willow/tools/willowc/main.cpp
new file mode 100644
index 0000000..237c8ce
--- /dev/null
+++ b/willow/tools/willowc/main.cpp
@@ -0,0 +1 @@
+int main() {}