Subzero. WASM. Additional progress.
This change includes a number of improvements since the last WASM
CL. It compiles against a newer version of V8 that matches the current
WASM binary format. Many more WASM instructions are supported, as well
as global variable initializers.
There is also the beginning of a runtime library that implements some
system calls required by the WASM C library. The c2wasm-exe.sh script
can be used to compile a C program to a .wasm module, which is then
compiled by Subzero into a native executable.
This change includes a new Breakpoint instruction, which inserts an
unconditional breakpoint into the executable. This has been helpful in
debugging code generation for some WASM instructions. The Breakpoint
instruction is only completely implemented on X86.
BUG= https://bugs.chromium.org/p/nativeclient/issues/detail?id=4369
R=stichnot@chromium.org
Review URL: https://codereview.chromium.org/1876413002 .
diff --git a/runtime/wasm-runtime.c b/runtime/wasm-runtime.c
new file mode 100644
index 0000000..0ffb6ca
--- /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$$__syscall4(int Which, int VarArgs) {
+ int Fd = WASM_DEREF(int, VarArgs + 0 * sizeof(int));
+ int Buffer = WASM_DEREF(int, VarArgs + 1 * sizeof(int));
+ int Length = WASM_DEREF(int, VarArgs + 2 * sizeof(int));
+
+ return write(Fd, WASM_REF(char *, Buffer), Length);
+}
+
+/// sys_ioctl
+int env$$__syscall54(int A, int B) {
+ int Fd = WASM_DEREF(int, B + 0 * sizeof(int));
+ int Op = WASM_DEREF(int, B + 1 * 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;
+}
