Fix ucontext structure for Android on x86

src/platform-linux.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 948 matching lines @@
 typedef struct ucontext {
   uint32_t uc_flags;
   struct ucontext* uc_link;
   stack_t uc_stack;
   mcontext_t uc_mcontext;
   __sigset_t uc_sigmask;
 } ucontext_t;
 
 #elif !defined(__GLIBC__) && defined(__i386__)
 // x86 version for Android.
-struct _libc_fpreg {
-  uint16_t significand[4];
-  uint16_t exponent;
+struct sigcontext {
+  uint32_t gregs[19];
+  void* fpregs;
+  uint32_t oldmask;
+  uint32_t cr2;
 };
 
-struct _libc_fpstate {
-  uint64_t cw;
-  uint64_t sw;
-  uint64_t tag;
-  uint64_t ipoff;
-  uint64_t cssel;
-  uint64_t dataoff;
-  uint64_t datasel;
-  struct _libc_fpreg _st[8];
-  uint64_t status;
-};
-
-typedef struct _libc_fpstate *fpregset_t;
-
-typedef struct mcontext {
-  int32_t gregs[19];
-  fpregset_t fpregs;
-  int64_t oldmask;
-  int64_t cr2;
-} mcontext_t;
-
-typedef uint64_t __sigset_t;
-
+typedef uint32_t __sigset_t;
+typedef struct sigcontext mcontext_t;
 typedef struct ucontext {
-  uint64_t uc_flags;
-  struct ucontext *uc_link;
+  uint32_t uc_flags;
+  struct ucontext* uc_link;
   stack_t uc_stack;
   mcontext_t uc_mcontext;
   __sigset_t uc_sigmask;
-  struct _libc_fpstate __fpregs_mem;
 } ucontext_t;
-
 enum { REG_EBP = 6, REG_ESP = 7, REG_EIP = 14 };
 #endif
 
 
 static int GetThreadID() {
   // Glibc doesn't provide a wrapper for gettid(2).
 #if defined(ANDROID)
   return syscall(__NR_gettid);
 #else
   return syscall(SYS_gettid);
@@ skipping 289 matching lines @@
 
 
 void Sampler::Stop() {
   ASSERT(IsActive());
   SignalSender::RemoveActiveSampler(this);
   SetActive(false);
 }
 
 
 } }  // namespace v8::internal