MIPS: Enable serialization for MIPS architecture.

src/serialize.cc

Index: src/serialize.cc
diff --git a/src/serialize.cc b/src/serialize.cc
index 4249d369d54a49487baccc0522f95a85fc17294e..8757d1427806a779cdb74f5a5705fbfd0ce0a45f 100644
--- a/src/serialize.cc
+++ b/src/serialize.cc
@@ -777,6 +777,14 @@ void Deserializer::ReadObject(int space_number,
 
 static const int kUnknownOffsetFromStart = -1;
 
+#ifdef V8_TARGET_ARCH_MIPS
+#define PATCH_SITE_ADJUST(addr)                                                \
+  (addr - 3 * kPointerSize)

[Erik Corry, 2012/03/17 02:49:18]

This should be kInstructionSize (and I moved the functionality into the MIPS
assembler instead of this ifdef).

+#else
+#define PATCH_SITE_ADJUST(addr)                                                \
+  (addr)
+#endif
+
 
 void Deserializer::ReadChunk(Object** current,
                              Object** limit,
@@ -849,7 +857,11 @@ void Deserializer::ReadChunk(Object** current,
           if (how == kFromCode) {                                              \
             Address location_of_branch_data =                                  \
                 reinterpret_cast<Address>(current);                            \

[Erik Corry, 2012/03/17 02:49:18]

It turns out this code can be simplified a little for all architecture, since
the kFromCode instructions are only emitted if the current_was_incremented
handling needs to be special in some way, and the PATCH_SITE_ADJUST ugliness can
be moved into the assembler.

-            Assembler::set_target_at(location_of_branch_data,                  \
+            Address patch_site = PATCH_SITE_ADJUST(location_of_branch_data);   \
+            if (patch_site != location_of_branch_data) {                       \
+              current_was_incremented = true;                                  \
+            }                                                                  \
+            Assembler::set_target_at(patch_site,                               \
                                      reinterpret_cast<Address>(new_object));   \
             if (within == kFirstInstruction) {                                 \
               location_of_branch_data += Assembler::kCallTargetSize;           \
@@ -983,6 +995,11 @@ void Deserializer::ReadChunk(Object** current,
       // Deserialize a new object and write a pointer to it to the current
       // object.
       ONE_PER_SPACE(kNewObject, kPlain, kStartOfObject)
+      // Deserialize a new object from pointer found in code and write
+      // a pointer to it to the current object. Required only for MIPS.
+#if V8_TARGET_ARCH_MIPS
+      ONE_PER_SPACE(kNewObject, kFromCode, kStartOfObject)
+#endif
       // Support for direct instruction pointers in functions
       ONE_PER_CODE_SPACE(kNewObject, kPlain, kFirstInstruction)
       // Deserialize a new code object and write a pointer to its first
@@ -992,6 +1009,10 @@ void Deserializer::ReadChunk(Object** current,
       // allocation point and write a pointer to it to the current object.
       ALL_SPACES(kBackref, kPlain, kStartOfObject)
       // Find a recently deserialized code object using its offset from the
+      // current allocation point and write a pointer to it to the current
+      // object. Required only for MIPS.
+      ALL_SPACES(kBackref, kFromCode, kStartOfObject)

[Erik Corry, 2012/03/17 02:49:18]

The order is not important here so I moved these into the ifdef above for a tiny
code size improvement without an increase in the number of ifdefs.

+      // Find a recently deserialized code object using its offset from the
       // current allocation point and write a pointer to its first instruction
       // to the current code object or the instruction pointer in a function
       // object.
@@ -1005,6 +1026,10 @@ void Deserializer::ReadChunk(Object** current,
       // start and write a pointer to its first instruction to the current code
       // object.
       ALL_SPACES(kFromStart, kFromCode, kFirstInstruction)
+      // Find an already deserialized code object using its offset from
+      // the start and write a pointer to it to the current object.
+      // Required only for MIPS.
+      ALL_SPACES(kFromStart, kFromCode, kStartOfObject)
       // Find an object in the roots array and write a pointer to it to the
       // current object.
       CASE_STATEMENT(kRootArray, kPlain, kStartOfObject, 0)