Subzero, Wasm: Dynamically reallocate read buffer. Runtime improvements.

runtime/wasm-runtime.cpp

 //===- subzero/runtime/wasm-runtime.cpp - 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 <cassert>
 #include <cmath>
-// TODO (eholk): change to cstdint
+#include <errno.h>
+#include <fcntl.h>
+#include <iostream>
+#include <math.h>
 #include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <termios.h>
+#include <time.h>
+#include <unistd.h>
+
+#ifdef WASM_TRACE_RUNTIME
+#define TRACE_ENTRY()                                                          \
+  { std::cerr << __func__ << "(...) = "; }
+template <typename T> T trace(T x) {
+  std::cerr << x << std::endl;
+  return x;
+}
+void trace() { std::cerr << "(void)" << std::endl; }
+#else
+#define TRACE_ENTRY()
+template <typename T> T trace(T x) { return x; }
+void trace() {}
+#endif // WASM_TRACE_RUNTIME
+
+extern "C" {
+extern char WASM_MEMORY[];
+extern uint32_t WASM_DATA_SIZE;
+extern uint32_t WASM_NUM_PAGES;
+} // end of extern "C"
 
 namespace {
 uint32_t HeapBreak;
 
 // TODO (eholk): make all of these constexpr.
 const uint32_t PageSizeLog2 = 16;
 const uint32_t PageSize = 1 << PageSizeLog2; // 64KB
 const uint32_t StackPtrLoc = 1024;           // defined by emscripten
 
 uint32_t pageNum(uint32_t Index) { return Index >> PageSizeLog2; }
 } // end of anonymous namespace
 
 namespace env {
 double floor(double X) { return std::floor(X); }
 
 float floor(float X) { return std::floor(X); }
 } // end of namespace env
 
 // TODO (eholk): move the C parts outside and use C++ name mangling.
+
+namespace {
+
+/// Some runtime functions need to return pointers. The WasmData struct is used
+/// to preallocate space for these on the heap.
+struct WasmData {
+
+  /// StrBuf is returned by functions that return strings.
+  char StrBuf[256];
+};
+
+WasmData *GlobalData = NULL;
+
+int toWasm(void *Ptr) {
+  return reinterpret_cast<int>(reinterpret_cast<char *>(Ptr) - WASM_MEMORY);
+}
+
+template <typename T> T *wasmPtr(int Index) {
+  if (pageNum(Index) < WASM_NUM_PAGES) {
+    return reinterpret_cast<T *>(WASM_MEMORY + Index);
+  }
+  abort();
+}
+
+template <typename T> class WasmPtr {
+  int Ptr;
+
+public:
+  WasmPtr(int Ptr) : Ptr(Ptr) {
+    // TODO (eholk): make this a static_assert once we have C++11
+    assert(sizeof(*this) == sizeof(int));
+  }
+
+  WasmPtr(T *Ptr) : Ptr(toWasm(Ptr)) {}
+
+  T &operator*() const { return *asPtr(); }
+
+  T *asPtr() const { return wasmPtr<T>(Ptr); }
+
+  int asInt() const { return Ptr; }
+};
+
+template <typename T> class WasmArray {
+  int Ptr;
+
+public:
+  WasmArray(int Ptr) : Ptr(Ptr) {
+    // TODO (eholk): make this a static_assert once we have C++11.
+    assert(sizeof(*this) == sizeof(int));
+  }
+
+  T &operator[](unsigned int Index) const { return wasmPtr<T>(Ptr)[Index]; }
+};
+} // end of anonymous namespace
+
+// TODO (eholk): move the C parts outside and use C++ name mangling.
 extern "C" {
-#include <errno.h>
-#include <fcntl.h>
-#include <math.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
 
-extern char WASM_MEMORY[];
-extern uint32_t WASM_DATA_SIZE;
-extern uint32_t WASM_NUM_PAGES;
+void __Sz_bounds_fail() {
+  std::cerr << "Bounds check failure" << std::endl;
+  abort();
+}
+
+void __Sz_indirect_fail() {
+  std::cerr << "Invalid indirect call target" << std::endl;
+  abort();
+}
 
 void env$$abort() {
   fprintf(stderr, "Aborting...\n");
   abort();
 }
 
 void env$$_abort() { env$$abort(); }
 
-double env$$floor_f(float X) { return env::floor(X); }
-double env$$floor_d(double X) { return env::floor(X); }
+double env$$floor_f(float X) {
+  TRACE_ENTRY();
+  return env::floor(X);
+}
+double env$$floor_d(double X) {
+  TRACE_ENTRY();
+  return env::floor(X);
+}
 
-void env$$exit(int Status) { exit(Status); }
-void env$$_exit(int Status) { env$$exit(Status); }
+void env$$exit(int Status) {
+  TRACE_ENTRY();
+  exit(Status);
+}
+void env$$_exit(int Status) {
+  TRACE_ENTRY();
+  env$$exit(Status);
+}
 
 #define UNIMPLEMENTED(f)                                                       \
   void env$$##f() {                                                            \
     fprintf(stderr, "Unimplemented: " #f "\n");                                \
     abort();                                                                   \
   }
 
 int32_t env$$sbrk(int32_t Increment) {
+  TRACE_ENTRY();
+  uint32_t OldBreak = HeapBreak;
   HeapBreak += Increment;
-  return HeapBreak;
-}
-
-UNIMPLEMENTED(setjmp)
-UNIMPLEMENTED(longjmp)
+  return trace(OldBreak);
+}
+
+UNIMPLEMENTED(__addtf3)
 UNIMPLEMENTED(__assert_fail)
-UNIMPLEMENTED(__builtin_malloc)
+UNIMPLEMENTED(__builtin_apply)
+UNIMPLEMENTED(__builtin_apply_args)
 UNIMPLEMENTED(__builtin_isinff)
 UNIMPLEMENTED(__builtin_isinfl)
-UNIMPLEMENTED(__builtin_apply)
-UNIMPLEMENTED(__builtin_apply_args)
-UNIMPLEMENTED(pthread_cleanup_push)
-UNIMPLEMENTED(pthread_cleanup_pop)
-UNIMPLEMENTED(pthread_self)
+UNIMPLEMENTED(__builtin_malloc)
+UNIMPLEMENTED(__divtf3)
+UNIMPLEMENTED(__eqtf2)
+UNIMPLEMENTED(__extenddftf2)
+UNIMPLEMENTED(__extendsftf2)
+UNIMPLEMENTED(__fixsfti)
+UNIMPLEMENTED(__fixtfdi)
+UNIMPLEMENTED(__fixtfsi)
+UNIMPLEMENTED(__fixunstfsi)
 UNIMPLEMENTED(__floatditf)
 UNIMPLEMENTED(__floatsitf)
-UNIMPLEMENTED(__fixtfdi)
-UNIMPLEMENTED(__fixtfsi)
-UNIMPLEMENTED(__fixsfti)
-UNIMPLEMENTED(__netf2)
+UNIMPLEMENTED(__floatunsitf)
 UNIMPLEMENTED(__getf2)
-UNIMPLEMENTED(__eqtf2)
+UNIMPLEMENTED(__letf2)
 UNIMPLEMENTED(__lttf2)
-UNIMPLEMENTED(__addtf3)
-UNIMPLEMENTED(__subtf3)
-UNIMPLEMENTED(__divtf3)
 UNIMPLEMENTED(__multf3)
 UNIMPLEMENTED(__multi3)
-UNIMPLEMENTED(__lock)
-UNIMPLEMENTED(__unlock)
-UNIMPLEMENTED(__syscall6)   // sys_close
+UNIMPLEMENTED(__netf2)
+UNIMPLEMENTED(__subtf3)
 UNIMPLEMENTED(__syscall140) // sys_llseek
+UNIMPLEMENTED(__syscall221) // sys_fcntl64
+UNIMPLEMENTED(__trunctfdf2)
+UNIMPLEMENTED(__trunctfsf2)
 UNIMPLEMENTED(__unordtf2)
-UNIMPLEMENTED(__fixunstfsi)
-UNIMPLEMENTED(__floatunsitf)
-UNIMPLEMENTED(__extenddftf2)
-
-void *wasmPtr(uint32_t Index) {
-  if (pageNum(Index) < WASM_NUM_PAGES) {
-    return WASM_MEMORY + Index;
-  }
-  abort();
-}
-
-extern int __szwasm_main(int, const char **);
-
-#define WASM_REF(Type, Index) ((Type *)wasmPtr(Index))
+UNIMPLEMENTED(longjmp)
+UNIMPLEMENTED(pthread_cleanup_pop)
+UNIMPLEMENTED(pthread_cleanup_push)
+UNIMPLEMENTED(pthread_self)
+UNIMPLEMENTED(setjmp)
+
+// The empty comment is to keep clang-fmt from breaking this pre-C++11 code.

[Jim Stichnoth, 2016/04/29 20:57:38]

lol

+extern int __szwasm_main(int, WasmPtr<WasmPtr<char> /**/>);
+
+#define WASM_REF(Type, Index) (WasmPtr<Type>(Index).asPtr())
 #define WASM_DEREF(Type, Index) (*WASM_REF(Type, Index))
 
 int main(int argc, const char **argv) {
+  // fprintf(stderr, "main(%d)\n", argc);

[Jim Stichnoth, 2016/04/29 20:57:38]

remove?

[Eric Holk, 2016/04/29 21:42:55]

Done.

+
+  // TODO (eholk): align these allocations correctly.
+
+  // Allocate space for the global data.
+  HeapBreak = WASM_DATA_SIZE;
+  GlobalData = WASM_REF(WasmData, HeapBreak);
+  HeapBreak += sizeof(WasmData);
+
+  // copy the command line arguments.
+  // The empty comment is to keep clang-fmt from breaking this pre-C++11 code.
+  WasmPtr<WasmPtr<char> /**/> WasmArgV = HeapBreak;

[Jim Stichnoth, 2016/04/29 20:57:38]

You could also consider making WasmPtr<char> into a typedef.

[Eric Holk, 2016/04/29 21:42:55]

Good idea. Done.

+  WasmPtr<char> *WasmArgVPtr = WasmArgV.asPtr();
+  HeapBreak += argc * sizeof(*WasmArgVPtr);
+
+  for (int i = 0; i < argc; ++i) {
+    WasmArgVPtr[i] = HeapBreak;
+    strcpy(WASM_REF(char, HeapBreak), argv[i]);
+    HeapBreak += strlen(argv[i]) + 1;
+  }
+
   // Initialize the break to the nearest page boundary after the data segment
   HeapBreak = (WASM_DATA_SIZE + PageSize - 1) & ~(PageSize - 1);
 
   // Initialize the stack pointer.
   WASM_DEREF(int32_t, StackPtrLoc) = WASM_NUM_PAGES << PageSizeLog2;
 
-  return __szwasm_main(argc, argv);
-}
-
-int env$$abs(int a) { return abs(a); }
-
-double env$$pow(double x, double y) { return pow(x, y); }
+  return __szwasm_main(argc, WasmArgV);
+}
+
+int env$$abs(int a) {
+  TRACE_ENTRY();
+  return trace(abs(a));
+}
+
+clock_t env$$clock() {
+  TRACE_ENTRY();
+  return trace(clock());
+}
+
+int env$$ctime(WasmPtr<time_t> Time) {
+  TRACE_ENTRY();
+  char *CTime = ctime(Time.asPtr());
+  strncpy(GlobalData->StrBuf, CTime, sizeof(GlobalData->StrBuf));
+  GlobalData->StrBuf[sizeof(GlobalData->StrBuf) - 1] = '\0';
+  return trace(WasmPtr<char>(GlobalData->StrBuf).asInt());
+}
+
+double env$$pow(double x, double y) {
+  TRACE_ENTRY();
+  return trace(pow(x, y));
+}
+
+time_t env$$time(WasmPtr<time_t> Time) {
+  TRACE_ENTRY();
+  time_t *TimePtr = WASM_REF(time_t, Time);
+  return trace(time(TimePtr));
+}
+
+// lock and unlock are no-ops in wasm.js, so we mimic that behavior.
+void env$$__lock(int32_t _) {
+  TRACE_ENTRY();
+  (void)_;

[Jim Stichnoth, 2016/04/29 20:57:38]

Can you just omit the argument name in the declaration above, and then remove
this void cast?

[Eric Holk, 2016/04/29 21:42:55]

Ah, that seems to work. I seem to remember that not working the last time I
tried, so I'm not sure what happened.

Done.

+  trace();
+}
+
+void env$$__unlock(int32_t _) {
+  TRACE_ENTRY();
+  (void)_;
+  trace();
+}
+
+/// sys_read
+int env$$__syscall3(int Which, WasmArray<int> VarArgs) {
+  TRACE_ENTRY();
+  int Fd = VarArgs[0];
+  int Buffer = VarArgs[1];
+  int Length = VarArgs[2];
+
+  return trace(read(Fd, WASM_REF(char *, Buffer), Length));
+}
 
 /// sys_write
-int env$$__syscall4(int Which, int VarArgs) {
-  int Fd = WASM_DEREF(int, VarArgs + 0 * sizeof(int));
-  int Buffer = WASM_DEREF(int, VarArgs + 1 * sizeof(int));
-  int Length = WASM_DEREF(int, VarArgs + 2 * sizeof(int));
-
-  return write(Fd, WASM_REF(char *, Buffer), Length);
+int env$$__syscall4(int Which, WasmArray<int> VarArgs) {
+  TRACE_ENTRY();
+  int Fd = VarArgs[0];
+  int Buffer = VarArgs[1];
+  int Length = VarArgs[2];
+
+  return trace(write(Fd, WASM_REF(char *, Buffer), Length));
 }
 
 /// sys_open
-int env$$__syscall5(int Which, int VarArgs) {
-  int WasmPath = WASM_DEREF(int, VarArgs);
-  int Flags = WASM_DEREF(int, VarArgs + 4);
-  int Mode = WASM_DEREF(int, VarArgs + 8);
+int env$$__syscall5(int Which, WasmArray<int> VarArgs) {
+  TRACE_ENTRY();
+  int WasmPath = VarArgs[0];
+  int Flags = VarArgs[1];
+  int Mode = VarArgs[2];
   const char *Path = WASM_REF(char, WasmPath);
 
-  fprintf(stderr, "sys_open(%s, %d, %d)\n", Path, Flags, Mode);
-
-  return open(Path, Flags, Mode);
+  return trace(open(Path, Flags, Mode));
+}
+
+/// sys_close
+int env$$__syscall6(int Which, WasmArray<int> VarArgs) {
+  TRACE_ENTRY();
+  int Fd = VarArgs[0];
+
+  return trace(close(Fd));
+}
+
+/// sys_unlink
+int env$$__syscall10(int Which, WasmArray<int> VarArgs) {
+  TRACE_ENTRY();
+  int WasmPath = VarArgs[0];
+  const char *Path = WASM_REF(char, WasmPath);
+
+  return trace(unlink(Path));
 }
 
 /// sys_getpid
-int env$$__syscall20(int Which, int VarArgs) {
+int env$$__syscall20(int Which, WasmArray<int> VarArgs) {
+  TRACE_ENTRY();
   (void)Which;
   (void)VarArgs;
 
-  return getpid();
+  return trace(getpid());
+}
+
+/// sys_rmdir
+int env$$__syscall40(int Which, WasmArray<int> VarArgs) {
+  TRACE_ENTRY();
+  int WasmPath = VarArgs[0];
+  const char *Path = WASM_REF(char, WasmPath);
+
+  return trace(rmdir(Path));
 }
 
 /// sys_ioctl
-int env$$__syscall54(int A, int B) {
-  int Fd = WASM_DEREF(int, B + 0 * sizeof(int));
-  int Op = WASM_DEREF(int, B + 1 * sizeof(int));
-  int ArgP = WASM_DEREF(int, B + 2 * sizeof(int));
-  // TODO (eholk): implement sys_ioctl
-  return -ENOTTY;
-}
-
-/// sys_write
-int env$$__syscall146(int Which, int VarArgs) {
-
-  int Fd = WASM_DEREF(int, VarArgs);
-  int Iov = WASM_DEREF(int, VarArgs + sizeof(int));
-  int Iovcnt = WASM_DEREF(int, VarArgs + 2 * sizeof(int));
+int env$$__syscall54(int Which, WasmArray<int> VarArgs) {
+  TRACE_ENTRY();
+  int Fd = VarArgs[0];
+  int Op = VarArgs[1];
+  int ArgP = VarArgs[2];
+
+  switch (Op) {
+  case TCGETS: {
+    // struct termios has no pointers. Otherwise, we'd have to rewrite them.
+    struct termios *TermIOS = WASM_REF(struct termios, ArgP);
+    return trace(ioctl(Fd, TCGETS, TermIOS));
+  }
+  default:
+    // TODO (eholk): implement more ioctls
+    return trace(-ENOTTY);
+  }
+}
+
+struct IoVec {
+  WasmPtr<char> Ptr;
+  int Length;
+};
+
+/// sys_readv
+int env$$__syscall145(int Which, WasmArray<int> VarArgs) {
+  TRACE_ENTRY();
+  int Fd = VarArgs[0];
+  WasmArray<IoVec> Iov = VarArgs[1];
+  int Iovcnt = VarArgs[2];
 
   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);
-
-    int Curr = write(Fd, Ptr, Length);
+    int Curr = read(Fd, Iov[I].Ptr.asPtr(), Iov[I].Length);
 
     if (Curr < 0) {
-      return -1;
+      return trace(-1);
     }
     Count += Curr;
   }
-  return Count;
+  return trace(Count);
+}
+
+/// sys_writev
+int env$$__syscall146(int Which, WasmArray<int> VarArgs) {
+  TRACE_ENTRY();
+  int Fd = VarArgs[0];
+  WasmArray<IoVec> Iov = VarArgs[1];
+  int Iovcnt = VarArgs[2];
+
+  int Count = 0;
+
+  for (int I = 0; I < Iovcnt; ++I) {
+    int Curr = write(Fd, Iov[I].Ptr.asPtr(), Iov[I].Length);
+
+    if (Curr < 0) {
+      return trace(-1);
+    }
+    Count += Curr;
+  }
+  return trace(Count);
 }
 
 /// sys_mmap_pgoff
-int env$$__syscall192(int Which, int VarArgs) {
+int env$$__syscall192(int Which, WasmArray<int> VarArgs) {
+  TRACE_ENTRY();
   (void)Which;
   (void)VarArgs;
 
   // TODO (eholk): figure out how to implement this.
 
-  return -ENOMEM;
+  return trace(-ENOMEM);
 }
 } // end of extern "C"