1 files changed, 218 insertions, 0 deletions
diff --git a/src/s2wasm.h b/src/s2wasm.h
new file mode 100644
index 000000000..e6782a284
--- /dev/null
+++ b/src/s2wasm.h
@@ -0,0 +1,218 @@
+
+//
+// .s to WebAssembly translator.
+//
+
+#include "wasm.h"
+#include "parsing.h"
+
+namespace wasm {
+
+extern int debug; // wasm::debug is set in main(), typically from an env var
+
+//
+// S2WasmBuilder - parses a .s file into WebAssembly
+//
+
+class S2WasmBuilder {
+  AllocatingModule& wasm;
+  MixedArena& allocator;
+  char *s;
+
+public:
+  S2WasmBuilder(AllocatingModule& wasm, char *s) : wasm(wasm), allocator(wasm.allocator), s(s) {
+    process();
+  }
+
+private:
+  // utilities
+
+  void skipWhitespace() {
+    while (1) {
+      while (*s && isspace(*s)) s++;
+      if (*s != '#') break;
+      while (*s != '\n') s++;
+    }
+  }
+
+  void findComma() {
+    while (*s && *s != ',') s++;
+    s++;
+    skipWhitespace();
+  }
+
+  // match and skip the pattern, if matched
+  bool match(const char *pattern) {
+    size_t size = strlen(pattern);
+    if (strncmp(s, pattern, size) == 0) {
+      s += size;
+      skipWhitespace();
+      return true;
+    }
+    return false;
+  }
+
+  void mustMatch(const char *pattern) {
+    bool matched = match(pattern);
+    assert(matched);
+  }
+
+  #define abort_on(why) {          \
+    printf("%s : %20s\n", why, s); \
+    abort();                       \
+  }
+
+  void dump(const char *text) {
+    std::cerr << text << "\n==========\n" << s << "\n==========\n";
+  }
+
+  Name getStr() {
+    std::string str;
+    while (*s && !isspace(*s)) {
+      str += *s;
+      s++;
+    }
+    return cashew::IString(str.c_str(), false);
+  }
+
+  WasmType getType() {
+    if (match("i32")) return i32;
+    if (match("i64")) return i64;
+    if (match("f32")) return f32;
+    if (match("f64")) return f64;
+    abort_on("getType");
+  }
+
+  // state
+
+  typedef std::pair<Const*, Name> Addressing;
+  std::vector<Addressing> addressings;
+
+  // processors
+
+  void process() {
+    while (*s) {
+      skipWhitespace();
+      if (!*s) break;
+      if (*s != '.') break;
+      s++;
+      if (match("text")) parseText();
+      else if (match("data")) parseData();
+      else abort_on(s);
+    }
+  }
+
+  void parseText() {
+    while (*s) {
+      skipWhitespace();
+      if (!*s) break;
+      if (*s != '.') break;
+      s++;
+      if (match("file")) parseFile();
+      else if (match("globl")) parseGlobl();
+      else abort_on(s);
+    }
+  }
+
+  void parseFile() {
+    assert(*s == '"');
+    s++;
+    std::string filename;
+    while (*s != '"') {
+      filename += *s;
+      s++;
+    }
+    s++;
+    // TODO: use the filename?
+  }
+
+  void parseGlobl() {
+    unsigned nextId = 0;
+    auto getNextId = [&nextId]() {
+      return cashew::IString(('$' + std::to_string(nextId++)).c_str(), false);
+    };
+
+    Name name = getStr();
+    skipWhitespace();
+    mustMatch(".type");
+    mustMatch(name.str);
+    mustMatch(",@function");
+    mustMatch(name.str);
+    mustMatch(":");
+    auto func = allocator.alloc<Function>();
+    // params and result
+    while (1) {
+      if (match(".param")) {
+        while (1) {
+          func->params.emplace_back(getNextId(), getType());
+          skipWhitespace();
+          if (!match(",")) break;
+        }
+      } else if (match(".result")) {
+        func->result = getType();
+      } else break;
+    }
+    // parse body
+    auto currBlock = allocator.alloc<Block>();
+    func->body = currBlock;
+    std::vector<Expression*> stack;
+    auto push = [&](Expression* curr) {
+      stack.push_back(curr);
+    };
+    auto pop = [&]() {
+      Expression* ret = stack.back();
+      stack.pop_back();
+      return ret;
+    };
+    while (1) {
+      skipWhitespace();
+      if (match("i32.")) {
+        if (match("const")) {
+          mustMatch("$push");
+          findComma();
+          if (*s == '.') {
+            // global address
+            auto curr = allocator.alloc<Const>();
+            curr->type = i32;
+            addressings.emplace_back(curr, getStr());
+            push(curr);
+          } else {
+            // constant
+            push(parseConst(getStr(), i32, allocator));
+          }
+        }
+      } else if (match("return")) {
+        Block *temp;
+        if (!(func->body && (temp = func->body->dyn_cast<Block>()) && temp->name == FAKE_RETURN)) {
+          Expression* old = func->body;
+          temp = allocator.alloc<Block>();
+          temp->name = FAKE_RETURN;
+          if (old) temp->list.push_back(old);
+          func->body = temp;
+        }
+        auto curr = allocator.alloc<Break>();
+        curr->name = FAKE_RETURN;
+        if (*s == '$') {
+          getStr();
+          curr->value = pop();
+        }
+        currBlock->list.push_back(curr);
+      } else if (match("func_end0:")) {
+        mustMatch(".size");
+        mustMatch("main,");
+        mustMatch("func_end0-main");
+        wasm.addFunction(func);
+        return; // the function is done
+      } else {
+        break;
+      }
+    }
+  }
+
+  void parseData() {
+    abort();
+  }
+};
+
+} // namespace wasm
+