Add more generic version of reloc info padding to ensure enough space for rel...

src/ia32/lithium-codegen-ia32.h

Index: src/ia32/lithium-codegen-ia32.h
===================================================================
--- src/ia32/lithium-codegen-ia32.h	(revision 6848)
+++ src/ia32/lithium-codegen-ia32.h	(working copy)
@@ -60,6 +60,7 @@
         status_(UNUSED),
         deferred_(8),
         osr_pc_offset_(-1),
+        deoptimization_reloc_size(),
         resolver_(this) {
     PopulateDeoptimizationLiteralsWithInlinedFunctions();
   }
@@ -102,6 +103,20 @@
   // Emit frame translation commands for an environment.
   void WriteTranslation(LEnvironment* environment, Translation* translation);
 
+  void EnsureRelocSpaceForDeoptimization() {

[Søren Thygesen Gjesse, 2011/02/22 11:58:33]

Do we want this in the .h file (I guess we have no lithium-codegen-ia32-inl.h)?

[Rico, 2011/02/22 12:06:10]

Moved to the cc file

+    // Since we patch the reloc info with RUNTIME_ENTRY calls every patch
+    // site will take up 2 bytes + any pc-jumps.
+    // We are conservative and always reserver 6 bytes in case where a
+    // simple pc-jump is not enough.
+    uint32_t pc_delta =
+        masm()->pc_offset() - deoptimization_reloc_size.last_pc_offset;
+    if (is_uintn(pc_delta, 6)) {
+      deoptimization_reloc_size.min_size += 2;
+    } else {
+      deoptimization_reloc_size.min_size += 6;
+    }
+    deoptimization_reloc_size.last_pc_offset = masm()->pc_offset();
+  }
   // Declare methods that deal with the individual node types.
 #define DECLARE_DO(type) void Do##type(L##type* node);
   LITHIUM_CONCRETE_INSTRUCTION_LIST(DECLARE_DO)
@@ -151,6 +166,9 @@
   bool GeneratePrologue();
   bool GenerateBody();
   bool GenerateDeferredCode();
+  // Pad the reloc info to ensure that we have enough space to patch during
+  // deoptimization.
+  bool GenerateRelocPadding();
   bool GenerateSafepointTable();
 
   void CallCode(Handle<Code> code, RelocInfo::Mode mode, LInstruction* instr,
@@ -251,6 +269,13 @@
   ZoneList<LDeferredCode*> deferred_;
   int osr_pc_offset_;
 
+  struct DeoptimizationRelocSize {
+    int min_size;
+    int last_pc_offset;
+  };
+
+  DeoptimizationRelocSize deoptimization_reloc_size;
+
   // Builder that keeps track of safepoints in the code. The table
   // itself is emitted at the end of the generated code.
   SafepointTableBuilder safepoints_;