[wasm] Fix up mips & WasmCodeManager

Corrected mips code generation for WASM_CALL and JS_TO_WASM_CALL.

The logic for fetching raw call sites needed changing, too, in light
of mips' 2-instruction calls, where using target_address_address is
incorrect. The CL adds platform-specific accessors.

Bug: chromium:793292 chromium:793282
Change-Id: I879ea6bffdad60791d88a6f5ea15087cdcd3f2e9
Reviewed-on: https://chromium-review.googlesource.com/818460Reviewed-by: Ben Titzer <titzer@chromium.org>
Reviewed-by: Ivica Bogosavljevic <ivica.bogosavljevic@mips.com>
Commit-Queue: Mircea Trofin <mtrofin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50037}

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

@@ -787,7 +787,7 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
         __ Call(wasm_code, info()->IsWasm() ? RelocInfo::WASM_CALL
                                             : RelocInfo::JS_TO_WASM_CALL);
       } else {
-        __ Call(at, i.InputRegister(0), 0);
+        __ Call(i.InputRegister(0));
       }
       RecordCallPosition(instr);
       frame_access_state()->ClearSPDelta();
@@ -816,7 +816,7 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
         __ Jump(wasm_code, info()->IsWasm() ? RelocInfo::WASM_CALL
                                             : RelocInfo::JS_TO_WASM_CALL);
       } else {
-        __ Jump(at, i.InputRegister(0), 0);
+        __ Jump(i.InputRegister(0));
       }
       frame_access_state()->ClearSPDelta();
       frame_access_state()->SetFrameAccessToDefault();

src/mips/assembler-mips-inl.h

@@ -77,15 +77,13 @@ void RelocInfo::apply(intptr_t delta) {
 
 
 Address RelocInfo::target_address() {
-  DCHECK(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_));
+  DCHECK(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_) || IsWasmCall(rmode_));
   return Assembler::target_address_at(pc_, host_);
 }
 
 Address RelocInfo::target_address_address() {
-  DCHECK(IsCodeTarget(rmode_) ||
-         IsRuntimeEntry(rmode_) ||
-         rmode_ == EMBEDDED_OBJECT ||
-         rmode_ == EXTERNAL_REFERENCE);
+  DCHECK(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_) || IsWasmCall(rmode_) ||
+         rmode_ == EMBEDDED_OBJECT || rmode_ == EXTERNAL_REFERENCE);
   // Read the address of the word containing the target_address in an
   // instruction stream.
   // The only architecture-independent user of this function is the serializer.

src/mips64/assembler-mips64-inl.h

@@ -77,7 +77,7 @@ void RelocInfo::apply(intptr_t delta) {
 
 
 Address RelocInfo::target_address() {
-  DCHECK(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_));
+  DCHECK(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_) || IsWasmCall(rmode_));
   return Assembler::target_address_at(pc_, host_);
 }
 

src/wasm/wasm-code-manager.cc

@@ -506,8 +506,7 @@ void NativeModule::Link(uint32_t index) {
   for (RelocIterator it(code->instructions(), code->reloc_info(),
                         code->constant_pool(), mode_mask);
        !it.done(); it.next()) {
-    uint32_t index =
-        *(reinterpret_cast<uint32_t*>(it.rinfo()->target_address_address()));
+    uint32_t index = GetWasmCalleeTag(it.rinfo());
     const WasmCode* target = GetCode(index);
     if (target == nullptr) continue;
     Address target_addr = target->instructions().start();
@@ -976,6 +975,29 @@ NativeModuleModificationScope::~NativeModuleModificationScope() {
   }
 }
 
+// On Intel, call sites are encoded as a displacement. For linking
+// and for serialization/deserialization, we want to store/retrieve
+// a tag (the function index). On Intel, that means accessing the
+// raw displacement. Everywhere else, that simply means accessing
+// the target address.
+void SetWasmCalleeTag(RelocInfo* rinfo, uint32_t tag) {
+#if V8_TARGET_ARCH_X64 || V8_TARGET_ARCH_IA32
+  *(reinterpret_cast<uint32_t*>(rinfo->target_address_address())) = tag;
+#else
+  rinfo->set_target_address(nullptr, reinterpret_cast<Address>(tag),
+                            SKIP_WRITE_BARRIER, SKIP_ICACHE_FLUSH);
+#endif
+}
+
+uint32_t GetWasmCalleeTag(RelocInfo* rinfo) {
+#if V8_TARGET_ARCH_X64 || V8_TARGET_ARCH_IA32
+  return *(reinterpret_cast<uint32_t*>(rinfo->target_address_address()));
+#else
+  return static_cast<uint32_t>(
+      reinterpret_cast<size_t>(rinfo->target_address()));
+#endif
+}
+
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8

src/wasm/wasm-code-manager.h

@@ -414,6 +414,13 @@ class NativeModuleModificationScope final {
   NativeModule* native_module_;
 };
 
+// Utilities specific to wasm code generation. We embed a tag for call sites -
+// the index of the called function - when serializing and when creating the
+// code, initially. These APIs offer accessors. The implementation has platform
+// specific nuances.
+void SetWasmCalleeTag(RelocInfo* rinfo, uint32_t tag);
+uint32_t GetWasmCalleeTag(RelocInfo* rinfo);
+
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8

src/wasm/wasm-serialization.cc

@@ -24,18 +24,6 @@ namespace internal {
 namespace wasm {
 
 namespace {
-void SetRawTargetData(RelocInfo* rinfo, uint32_t value) {
-  if (rinfo->target_address_size() == sizeof(uint32_t)) {
-    *(reinterpret_cast<uint32_t*>(rinfo->target_address_address())) = value;
-    return;
-  } else {
-    DCHECK_EQ(rinfo->target_address_size(), sizeof(intptr_t));
-    DCHECK_EQ(rinfo->target_address_size(), 8);
-    *(reinterpret_cast<intptr_t*>(rinfo->target_address_address())) =
-        static_cast<intptr_t>(value);
-    return;
-  }
-}
 
 class Writer {
  public:
@@ -373,17 +361,17 @@ void NativeModuleSerializer::BufferCodeInAllocatedScratch(
       case RelocInfo::CODE_TARGET: {
         Address orig_target = orig_iter.rinfo()->target_address();
         uint32_t tag = EncodeBuiltinOrStub(orig_target);
-        SetRawTargetData(iter.rinfo(), tag);
+        SetWasmCalleeTag(iter.rinfo(), tag);
       } break;
       case RelocInfo::WASM_CALL: {
         Address orig_target = orig_iter.rinfo()->wasm_call_address();
         uint32_t tag = wasm_targets_lookup_[orig_target];
-        SetRawTargetData(iter.rinfo(), tag);
+        SetWasmCalleeTag(iter.rinfo(), tag);
       } break;
       case RelocInfo::RUNTIME_ENTRY: {
         Address orig_target = orig_iter.rinfo()->target_address();
         uint32_t tag = reference_table_lookup_[orig_target];
-        SetRawTargetData(iter.rinfo(), tag);
+        SetWasmCalleeTag(iter.rinfo(), tag);
       } break;
       default:
         UNREACHABLE();
@@ -579,8 +567,7 @@ bool NativeModuleDeserializer::ReadCode() {
                                         SKIP_WRITE_BARRIER);
       }
       case RelocInfo::CODE_TARGET: {
-        uint32_t tag = *(reinterpret_cast<uint32_t*>(
-            iter.rinfo()->target_address_address()));
+        uint32_t tag = GetWasmCalleeTag(iter.rinfo());
         Address target = GetTrampolineOrStubFromTag(tag);
         iter.rinfo()->set_target_address(nullptr, target, SKIP_WRITE_BARRIER,
                                          SKIP_ICACHE_FLUSH);