[wasm] remove faux code objects

src/compiler/wasm-compiler.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/wasm-compiler.h"
 
 #include "src/isolate-inl.h"
 
 #include "src/base/platform/elapsed-timer.h"
 #include "src/base/platform/platform.h"
@@ skipping 1890 matching lines @@
 
   *effect_ = call;
   return call;
 }
 
 Node* WasmGraphBuilder::CallDirect(uint32_t index, Node** args,
                                    wasm::WasmCodePosition position) {
   DCHECK_NULL(args[0]);
 
   // Add code object as constant.
-  args[0] = HeapConstant(module_->GetCodeOrPlaceholder(index));
+  args[0] =
+      jsgraph()->RelocatableInt32Constant(index, RelocInfo::WASM_DIRECT_CALL);
   wasm::FunctionSig* sig = module_->GetFunctionSignature(index);
 
   return BuildWasmCall(sig, args, position);
 }
 
 Node* WasmGraphBuilder::CallImport(uint32_t index, Node** args,
                                    wasm::WasmCodePosition position) {
   DCHECK_NULL(args[0]);
 
   // Add code object as constant.
@@ skipping 1380 matching lines @@
     double compile_ms = compile_timer.Elapsed().InMillisecondsF();
     PrintF("wasm-code-generation ok: %d bytes, %0.3f ms code generation\n",
            static_cast<int>(function_->code_end_offset -
                             function_->code_start_offset),
            compile_ms);
   }
 
   return code;
 }
 
+void Link(Isolate* isolate, std::vector<Handle<Code>>& functions) {

[ahaas, 2016/06/02 13:48:27]

What's the reason why you move the code for linking to wasm-compiler.cc? In my
understanding, wasm-compiler.cc contains code to compile a single wasm function,
and wasm-module.cc contains code to compile a set of functions, i.e. a whole
module. As linking processes a set of functions, I think that linking belongs to
wasm-module.cc.

[Mircea Trofin, 2016/06/02 14:46:21]

I didn't realize that was the separation. I thought module had to do with
instantiation (the term "module" is heavily overloaded through code :))

I'll move it back.

+  // On architectures supporting constant pools, if a function A calls another
+  // function B in a number of places, then the same slot in the constant pool
+  // would be used for the call to B. We can't update eagerly the location,
+  // because that would mean that the next time we look at the location to find
+  // the index of the function being called, we'd find the actual address
+  // instead. So we keep a worklist. To keep the code simple, we maintain the
+  // worklist even on architectures that do not support constant pools.
+  std::vector<std::pair<RelocInfo, Address>> worklist;
+  for (Handle<Code> code : functions) {
+    int mode_mask = RelocInfo::kWasmDirectCallMask;
+    AllowDeferredHandleDereference embedding_raw_address;
+    for (RelocIterator it(*code, mode_mask); !it.done(); it.next()) {
+      size_t f_index = it.rinfo()->wasm_function_index();
+      Handle<Code> code = functions[f_index];
+      worklist.push_back(
+          std::make_pair(*it.rinfo(), code->instruction_start()));
+    }
+    for (auto pair : worklist) {
+      pair.first.set_target_address(pair.second, SKIP_WRITE_BARRIER,
+                                    SKIP_ICACHE_FLUSH);
+    }
+    if (!worklist.empty()) {
+      worklist.clear();
+      Assembler::FlushICache(isolate, code->instruction_start(),
+                             code->instruction_size());
+    }
+  }
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8