[Courgette] Refactor: Add and use Instruction*Receptor classes; call ParseFile() in 2 passes.

courgette/adjustment_method_unittest.cc

 // Copyright (c) 2011 The Chromium 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 <memory>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/strings/string_util.h"
@@ skipping 31 matching lines @@
     abs32_rvas.push_back(kRvaB);
     std::vector<courgette::RVA> rel32_rvas;  // Stub.
 
     courgette::TrivialRvaVisitor abs32_visitor(abs32_rvas);
     courgette::TrivialRvaVisitor rel32_visitor(rel32_rvas);
     prog->PrecomputeLabels(&abs32_visitor, &rel32_visitor);
 
     courgette::Label* labelA = prog->FindAbs32Label(kRvaA);
     courgette::Label* labelB = prog->FindAbs32Label(kRvaB);
 
-    EXPECT_TRUE(prog->EmitAbs32(labelA));
-    EXPECT_TRUE(prog->EmitAbs32(labelA));
-    EXPECT_TRUE(prog->EmitAbs32(labelB));
-    EXPECT_TRUE(prog->EmitAbs32(labelA));
-    EXPECT_TRUE(prog->EmitAbs32(labelA));
-    EXPECT_TRUE(prog->EmitAbs32(labelB));
+    auto emit_all = [](courgette::Label* labelA, courgette::Label* labelB,
+                       courgette::InstructionReceptor* receptor) {
+      EXPECT_TRUE(receptor->EmitAbs32(labelA));
+      EXPECT_TRUE(receptor->EmitAbs32(labelA));
+      EXPECT_TRUE(receptor->EmitAbs32(labelB));
+      EXPECT_TRUE(receptor->EmitAbs32(labelA));
+      EXPECT_TRUE(receptor->EmitAbs32(labelA));
+      EXPECT_TRUE(receptor->EmitAbs32(labelB));
+    };
+
+    // Pass 1: Count the space needed to store instructions.
+    courgette::InstructionCountReceptor* count_receptor = nullptr;
+    EXPECT_TRUE(prog->CreateInstructionCountReceptor(&count_receptor));
+    emit_all(labelA, labelB, count_receptor);
+
+    // Pass 2: Emit all instructions to preallocated buffer (uses Phase 1
+    // count).
+    courgette::InstructionStoreReceptor* store_receptor = nullptr;
+    EXPECT_TRUE(prog->CreateInstructionStoreReceptor(&store_receptor));
+    emit_all(labelA, labelB, store_receptor);
 
     if (kind == 0) {
       labelA->index_ = 0;
       labelB->index_ = 1;
     } else {
       labelA->index_ = 1;
       labelB->index_ = 0;
     }
     prog->AssignRemainingIndexes();
 
@@ skipping 50 matching lines @@
   std::string s5 = Serialize(std::move(prog5));
   std::string s6 = Serialize(std::move(prog6));
 
   EXPECT_TRUE(s1 == s5);  // Adjustment did not change A (prog5)
   EXPECT_TRUE(s5 == s6);  // Adjustment did change B into A
 }
 
 TEST_F(AdjustmentMethodTest, All) {
   Test1();
 }