X87: [wasm] Relocatable Globals.

  port 2d1f977c (r36978)

  original commit message:
  Support for relocatable globals, to facilitate compilation before
  instantiation.

BUG=

Review-Url: https://codereview.chromium.org/2096273002
Cr-Commit-Position: refs/heads/master@{#37266}

src/compiler/x87/code-generator-x87.cc

@@ -61,6 +61,7 @@ class X87OperandConverter : public InstructionOperandConverter {
     Constant constant = ToConstant(operand);
     if (constant.type() == Constant::kInt32 &&
         (constant.rmode() == RelocInfo::WASM_MEMORY_REFERENCE ||
+         constant.rmode() == RelocInfo::WASM_GLOBAL_REFERENCE ||
          constant.rmode() == RelocInfo::WASM_MEMORY_SIZE_REFERENCE)) {
       return Immediate(reinterpret_cast<Address>(constant.ToInt32()),
                        constant.rmode());

src/x87/assembler-x87.cc

@@ -106,6 +106,11 @@ Address RelocInfo::wasm_memory_reference() {
   return Memory::Address_at(pc_);
 }
 
+Address RelocInfo::wasm_global_reference() {
+  DCHECK(IsWasmGlobalReference(rmode_));
+  return Memory::Address_at(pc_);
+}
+
 uint32_t RelocInfo::wasm_memory_size_reference() {
   DCHECK(IsWasmMemorySizeReference(rmode_));
   return Memory::uint32_at(pc_);
@@ -138,6 +143,19 @@ void RelocInfo::update_wasm_memory_reference(
   }
 }
 
+void RelocInfo::update_wasm_global_reference(
+    Address old_base, Address new_base, ICacheFlushMode icache_flush_mode) {
+  DCHECK(IsWasmGlobalReference(rmode_));
+  Address updated_reference;
+  DCHECK(old_base <= wasm_global_reference());
+  updated_reference = new_base + (wasm_global_reference() - old_base);
+  DCHECK(new_base <= updated_reference);
+  Memory::Address_at(pc_) = updated_reference;
+  if (icache_flush_mode != SKIP_ICACHE_FLUSH) {
+    Assembler::FlushICache(isolate_, pc_, sizeof(int32_t));
+  }
+}
+
 // -----------------------------------------------------------------------------
 // Implementation of Operand