S390: [wasm] Relocatable Globals.

Port 2d1f977c

Original commit message:

    Support for relocatable globals, to facilitate compilation before
    instantiation.

R=mtrofin@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com, mbrandy@us.ibm.com, bjaideep@ca.ibm.com

BUG=v8:5072
LOG=N

Review-Url: https://codereview.chromium.org/2071883002
Cr-Commit-Position: refs/heads/master@{#37041}

src/compiler/s390/code-generator-s390.cc

@@ -2001,6 +2001,7 @@ void CodeGenerator::AssembleMove(InstructionOperand* source,
           if (src.rmode() == RelocInfo::WASM_MEMORY_SIZE_REFERENCE) {
 #else
           if (src.rmode() == RelocInfo::WASM_MEMORY_REFERENCE ||
+              src.rmode() == RelocInfo::WASM_GLOBAL_REFERENCE ||
               src.rmode() == RelocInfo::WASM_MEMORY_SIZE_REFERENCE) {
 #endif
             __ mov(dst, Operand(src.ToInt32(), src.rmode()));
@@ -2010,7 +2011,8 @@ void CodeGenerator::AssembleMove(InstructionOperand* source,
           break;
         case Constant::kInt64:
 #if V8_TARGET_ARCH_S390X
-          if (src.rmode() == RelocInfo::WASM_MEMORY_REFERENCE) {
+          if (src.rmode() == RelocInfo::WASM_MEMORY_REFERENCE ||
+              src.rmode() == RelocInfo::WASM_GLOBAL_REFERENCE) {
             __ mov(dst, Operand(src.ToInt64(), src.rmode()));
           } else {
             DCHECK(src.rmode() != RelocInfo::WASM_MEMORY_SIZE_REFERENCE);

src/s390/assembler-s390.cc

@@ -228,6 +228,11 @@ uint32_t RelocInfo::wasm_memory_size_reference() {
       reinterpret_cast<intptr_t>(Assembler::target_address_at(pc_, host_)));
 }
 
+Address RelocInfo::wasm_global_reference() {
+  DCHECK(IsWasmGlobalReference(rmode_));
+  return Assembler::target_address_at(pc_, host_);
+}
+
 void RelocInfo::update_wasm_memory_reference(
     Address old_base, Address new_base, uint32_t old_size, uint32_t new_size,
     ICacheFlushMode icache_flush_mode) {
@@ -255,6 +260,17 @@ 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);
+  Assembler::set_target_address_at(isolate_, pc_, host_, updated_reference,
+                                   icache_flush_mode);
+}
+
 // -----------------------------------------------------------------------------
 // Implementation of Operand and MemOperand
 // See assembler-s390-inl.h for inlined constructors