Support compaction for code space pages.

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index 735466fe24e4e091484623ad9f84a7a37dc90cf3..f1c074eed687a6d3126f67065f9ffcba730c98f5 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -220,7 +220,11 @@ class RelocInfo BASE_EMBEDDED {
 
   RelocInfo() {}
   RelocInfo(byte* pc, Mode rmode, intptr_t data)
-      : pc_(pc), rmode_(rmode), data_(data) {
+      : pc_(pc), rmode_(rmode), data_(data), host_(NULL) {

[Erik Corry, 2011/09/06 14:10:31]

If you omit this function the compiler will help you find the places it was
called so you can verify that it is correct to pass NULL at this point.

[Vyacheslav Egorov (Chromium), 2011/09/06 15:01:42]

Done.

+  }
+
+  RelocInfo(byte* pc, Mode rmode, intptr_t data, Code* host)
+      : pc_(pc), rmode_(rmode), data_(data), host_(host) {
   }
 
   static inline bool IsConstructCall(Mode mode) {
@@ -261,6 +265,7 @@ class RelocInfo BASE_EMBEDDED {
   void set_pc(byte* pc) { pc_ = pc; }
   Mode rmode() const {  return rmode_; }
   intptr_t data() const { return data_; }
+  Code* host() const { return host_; }
 
   // Apply a relocation by delta bytes
   INLINE(void apply(intptr_t delta));
@@ -274,14 +279,14 @@ class RelocInfo BASE_EMBEDDED {
   // this relocation applies to;
   // can only be called if IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY
   INLINE(Address target_address());
-  INLINE(void set_target_address(Address target, Code* host));
+  INLINE(void set_target_address(Address target));
   INLINE(Object* target_object());
   INLINE(Handle<Object> target_object_handle(Assembler* origin));
   INLINE(Object** target_object_address());
-  INLINE(void set_target_object(Object* target, Code* code));
+  INLINE(void set_target_object(Object* target));
   INLINE(JSGlobalPropertyCell* target_cell());
   INLINE(Handle<JSGlobalPropertyCell> target_cell_handle());
-  INLINE(void set_target_cell(JSGlobalPropertyCell* cell, Code* code));
+  INLINE(void set_target_cell(JSGlobalPropertyCell* cell));
 
 
   // Read the address of the word containing the target_address in an
@@ -356,6 +361,7 @@ class RelocInfo BASE_EMBEDDED {
   byte* pc_;
   Mode rmode_;
   intptr_t data_;
+  Code* host_;
 #ifdef V8_TARGET_ARCH_MIPS
   // Code and Embedded Object pointers in mips are stored split
   // across two consecutive 32-bit instructions. Heap management