Remove fixed contant pool entries by caching some global constants in Thread

runtime/vm/thread.cc

Index: runtime/vm/thread.cc
diff --git a/runtime/vm/thread.cc b/runtime/vm/thread.cc
index ba6db93eacd7aeb166d49bbcbba0c59c8719d911..195642a1f848c92173ab2ae39d28eea8ba720609 100644
--- a/runtime/vm/thread.cc
+++ b/runtime/vm/thread.cc
@@ -5,8 +5,10 @@
 #include "vm/thread.h"
 
 #include "vm/isolate.h"
+#include "vm/object.h"
 #include "vm/os_thread.h"
 #include "vm/profiler.h"
+#include "vm/stub_code.h"
 #include "vm/thread_interrupter.h"
 
 
@@ -23,10 +25,21 @@ static void DeleteThread(void* thread) {
 }
 
 
-void Thread::InitOnce() {
+void Thread::InitOnceBeforeIsolate() {
   ASSERT(thread_key_ == OSThread::kUnsetThreadLocalKey);
   thread_key_ = OSThread::CreateThreadLocal(DeleteThread);
   ASSERT(thread_key_ != OSThread::kUnsetThreadLocalKey);
+  ASSERT(Thread::Current() == NULL);
+  // Postpone initialization of VM constants for this first thread.
+  SetCurrent(new Thread(false));
+}
+
+
+void Thread::InitOnceAfterObjectAndStubCode() {
+  Thread* thread = Thread::Current();
+  ASSERT(thread != NULL);
+  ASSERT(thread->isolate() == Dart::vm_isolate());
+  thread->InitVMConstants();
 }
 
 
@@ -53,6 +66,28 @@ void Thread::CleanUp() {
 #endif
 
 
+Thread::Thread(bool init_vm_constants)
+    : isolate_(NULL),
+      store_buffer_block_(NULL) {
+#define DEFAULT_INIT(type_name, member_name, init_expr, default_init_value)    \
+    member_name = default_init_value;

[koda, 2015/07/08 13:13:10]

Too much indentation.

[Florian Schneider, 2015/07/08 13:31:35]

Done.

+CACHED_CONSTANTS_LIST(DEFAULT_INIT)
+#undef DEFAULT_INIT
+  if (init_vm_constants) {
+    InitVMConstants();
+  }
+}
+
+
+void Thread::InitVMConstants() {
+#define INIT_VALUE(type_name, member_name, init_expr, default_init_value)      \
+  ASSERT(member_name == default_init_value);                                   \
+  member_name = init_expr;

[koda, 2015/07/08 13:13:10]

For the objects, we should probably ASSERT they are actually in the VM isolate.

Also, I suggest putting parentheses around init_expr for safety.

[Florian Schneider, 2015/07/08 13:31:35]

Done.

Asserting using IsVMHeapObject does not work because at Thread init-time the
Isolate::Current() is still NULL, and I get a segfault.

Is there any other way to check for VM isolate objects?


#0  0x00000000004273ca in dart::BaseIsolate::IncrementNoSafepointScopeDepth
(this=0x0) at runtime/vm/base_isolate.h:86
#1  0x000000000053e156 in dart::NoSafepointScope::NoSafepointScope
(this=0x7ffff5a63d48) at runtime/vm/heap.cc:747
#2  0x00000000006684dd in dart::ExclusivePageIterator::ExclusivePageIterator
(this=0x7ffff5a63d30, space=0xc1d7b0) at runtime/vm/pages.cc:443
#3  0x00000000006657ca in dart::PageSpace::Contains (this=0xc1d7b0,
addr=140737352585248) at runtime/vm/pages.cc:532
#4  0x000000000053c1f2 in dart::Heap::Contains (this=0xc1d260,
addr=140737352585248) at runtime/vm/heap.cc:197
#5  0x00000000006b0a40 in dart::RawObject::IsVMHeapObject (this=0x7ffff7e85021)
at runtime/vm/raw_object.cc:22
#6  0x0000000000724b21 in dart::Thread::InitVMConstants (this=0x7ffff00008c0) at
runtime/vm/thread.cc:85
#7  0x0000000000724b06 in dart::Thread::Thread (this=0x7ffff00008c0,
init_vm_constants=true) at runtime/vm/thread.cc:77
#8  0x0000000000724a8c in dart::Thread::EnsureInit () at runtime/vm/thread.cc:53
#9  0x0000000000727424 in dart::ThreadPool::Worker::Main (args=12777328) at
runtime/vm/thread_pool.cc:318
#10 0x0000000000662950 in dart::ThreadStart (data_ptr=0xc2f800) at
runtime/vm/os_thread_linux.cc:86
#11 0x00007ffff7bc4182 in start_thread (arg=0x7ffff5a64700) at
pthread_create.c:312
#12 0x00007ffff6edb47d in clone () at
../sysdeps/unix/sysv/linux/x86_64/clone.S:111

[koda, 2015/07/08 13:45:55]

Ah. This should go away soon, but for now you can just put the assertions in
"CanLoadFromThread" instead.

[koda, 2015/07/08 13:54:26]

... although at second thought, that might actually be too much of a slowdown
(iterating over the heap every time). At least assert that they are in old space
:)

+CACHED_CONSTANTS_LIST(INIT_VALUE)
+#undef INIT_VALUE
+}
+
+
 void Thread::EnterIsolate(Isolate* isolate) {
   Thread* thread = Thread::Current();
   ASSERT(thread != NULL);
@@ -168,4 +203,23 @@ void Thread::set_cha(CHA* value) {
   isolate_->cha_ = value;
 }
 
+
+bool Thread::CanLoadFromThread(const Object& object) {
+#define CHECK_OBJECT(type_name, member_name, expr, default_init_value)         \
+  if (object.raw() == expr) return true;
+CACHED_VM_OBJECTS_LIST(CHECK_OBJECT)
+#undef CHECK_OBJECT
+  return false;
+}
+
+
+intptr_t Thread::OffsetFromThread(const Object& object) {
+#define COMPUTE_OFFSET(type_name, member_name, expr, default_init_value)       \
+  if (object.raw() == expr) return Thread::member_name##offset();
+CACHED_VM_OBJECTS_LIST(COMPUTE_OFFSET)
+#undef COMPUTE_OFFSET
+  UNREACHABLE();
+  return -1;
+}
+
 }  // namespace dart