Subzero. WASM. Additional progress.

runtime/wasm-runtime.c

Index: runtime/wasm-runtime.c
diff --git a/runtime/wasm-runtime.c b/runtime/wasm-runtime.c
new file mode 100644
index 0000000000000000000000000000000000000000..283a094091429350d5eb08b91e79e82d5c43a60c
--- /dev/null
+++ b/runtime/wasm-runtime.c
@@ -0,0 +1,106 @@
+//===- subzero/runtime/wasm-runtime.c - Subzero WASM runtime source -------===//
+//
+//                        The Subzero Code Generator
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the system calls required by the libc that is included
+// in WebAssembly programs.
+//
+//===----------------------------------------------------------------------===//
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+extern char WASM_MEMORY[];
+
+void env$$abort() {
+  fprintf(stderr, "Aborting...\n");
+  abort();
+}
+
+void env$$_abort() { env$$abort(); }
+
+#define UNIMPLEMENTED(f)                                                       \
+  void env$$##f() {                                                            \
+    fprintf(stderr, "Unimplemented: " #f "\n");                                \
+    abort();                                                                   \
+  }
+
+UNIMPLEMENTED(sbrk)
+UNIMPLEMENTED(pthread_cleanup_push)
+UNIMPLEMENTED(pthread_cleanup_pop)
+UNIMPLEMENTED(pthread_self)
+UNIMPLEMENTED(__lock)
+UNIMPLEMENTED(__unlock)
+UNIMPLEMENTED(__syscall6)
+UNIMPLEMENTED(__syscall140)
+
+void *wasmPtr(int Index) {
+  // TODO (eholk): get the mask from the WASM file.
+  const int MASK = 0x3fffff;
+  Index &= MASK;
+
+  return WASM_MEMORY + Index;
+}
+
+extern int __szwasm_main(int, char **);
+
+#define WASM_REF(Type, Index) ((Type *)wasmPtr(Index))
+#define WASM_DEREF(Type, Index) (*WASM_REF(Type, Index))
+
+int main(int argc, char **argv) { return __szwasm_main(argc, argv); }
+
+/// sys_write
+int env$$__syscall4(int Which, int VarArgs) {
+  int Fd = WASM_DEREF(int, VarArgs);

[Jim Stichnoth, 2016/04/15 19:47:26]

Totally optional, but my OCD or whatever would have me writing it more like
this:

int xx = WASM_DEREF(int, VarArgs + 0 * sizeof(int));
int yy = WASM_DEREF(int, VarArgs + 1 * sizeof(int));
int zz = WASM_DEREF(int, VarArgs + 2 * sizeof(int));

[Eric Holk, 2016/04/15 20:05:16]

I agree. This is better. Done.

I think adding a WASM_ARRAY_REF(...) macro or something similar is probably the
right way to do it. I will probably add this as the runtime gets bigger.

+  int Buffer = WASM_DEREF(int, VarArgs + sizeof(int));
+  int Length = WASM_DEREF(int, VarArgs + 2 * sizeof(int));
+
+  return write(Fd, WASM_REF(char *, Buffer), Length);
+}
+
+/// sys_ioctl
+int env$$__syscall54(int A, int B) {
+  int Fd = WASM_DEREF(int, B);
+  int Op = WASM_DEREF(int, B + sizeof(int));
+  int ArgP = WASM_DEREF(int, B + 2 * sizeof(int));
+  // TODO (eholk): implement sys_ioctl
+  return -ENOTTY;
+}
+
+int env$$__syscall146(int Which, int VarArgs) {
+  fprintf(stderr, "syscall146\n");
+
+  int Fd = WASM_DEREF(int, VarArgs);
+  int Iov = WASM_DEREF(int, VarArgs + sizeof(int));
+  int Iovcnt = WASM_DEREF(int, VarArgs + 2 * sizeof(int));
+
+  fprintf(stderr, "  Fd=%d, Iov=%d (%p), Iovcnt=%d\n", Fd, Iov, wasmPtr(Iov),
+          Iovcnt);
+
+  int Count = 0;
+
+  for (int I = 0; I < Iovcnt; ++I) {
+    void *Ptr = WASM_REF(void, WASM_DEREF(int, Iov + I * 8));
+    int Length = WASM_DEREF(int, Iov + I * 8 + 4);
+
+    fprintf(stderr, "  [%d] write(%d, %p, %d) = ", I, Fd, Ptr, Length);
+    int Curr = write(Fd, Ptr, Length);
+
+    fprintf(stderr, "%d\n", Curr);
+
+    if (Curr < 0) {
+      return -1;
+    }
+    Count += Curr;
+  }
+  fprintf(stderr, "  Count = %d\n", Count);
+  return Count;
+}