[Syzygy Instrumenter] Add FillerTransform.

syzygy/instrument/transforms/filler_transform_unittest.cc

+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "syzygy/instrument/transforms/filler_transform.h"
+
+#include <set>
+
+#include "base/memory/scoped_ptr.h"
+#include "gtest/gtest.h"
+#include "syzygy/assm/assembler_base.h"
+#include "syzygy/block_graph/basic_block.h"
+#include "syzygy/block_graph/basic_block_assembler.h"
+#include "syzygy/block_graph/basic_block_subgraph.h"
+#include "syzygy/block_graph/basic_block_test_util.h"
+#include "syzygy/block_graph/block_graph.h"
+#include "syzygy/instrument/transforms/unittest_util.h"
+
+namespace instrument {
+namespace transforms {
+namespace {
+
+using block_graph::BasicBlock;
+using block_graph::BlockGraph;
+using block_graph::BasicCodeBlock;
+
+const char kNopName[] = "NOP";
+
+// Finds instruction indices and sizes of every NOP in @p instructions and
+// stores the result in @p nop_indices. Returns the @p instructions count.
+size_t FindAllNops(BasicBlock::Instructions* instructions,
+                   std::map<size_t, int>* nop_indices) {
+  size_t index = 0LL;
+  BasicBlock::Instructions::iterator inst_it = instructions->begin();
+  for (; inst_it != instructions->end(); ++inst_it, ++index) {
+    if (!::strcmp(inst_it->GetName(), kNopName))
+      (*nop_indices)[index] = inst_it->size();
+  }
+  return index;
+}
+
+class FillerBasicBlockTransformTest : public testing::Test {
+ public:
+  typedef testing::Test Super;
+  typedef FillerBasicBlockTransform::NopSizes NopSizes;
+  typedef FillerBasicBlockTransform::NopSpec NopSpec;
+
+  // Creates a new length @p n instruction list for testing.
+  void CreateInstructions(int n) {
+    using assm::eax;
+    using assm::ebp;
+    using assm::esp;
+    using assm::kSize32Bit;
+
+    instructions_.reset(new BasicBlock::Instructions);
+    if (n == 0)
+      return;
+
+    block_graph::BasicBlockAssembler
+        assm(instructions_->begin(), instructions_.get());
+    bool setup_stack = false;
+    --n;  // Reserve for ret.
+    if (n > 3) {
+      setup_stack = true;
+      n -= 3;  // Reserve for stack frame setup.
+    }
+    if (setup_stack) {
+      assm.push(ebp);
+      assm.mov(ebp, esp);
+    }
+    for (; n > 0; --n)
+      assm.mov(eax, block_graph::Immediate(n, kSize32Bit));
+    if (setup_stack)
+      assm.pop(ebp);
+    assm.ret(0);
+  }
+
+ protected:
+  scoped_ptr<BasicBlock::Instructions> instructions_;
+};
+
+class TestFillerTransform : public FillerTransform {
+ public:
+  explicit TestFillerTransform(const std::vector<std::string>& target_list)
+      : FillerTransform(target_list) { }
+};
+
+class FillerTransformTest : public testing::TestDllTransformTest {
+ public:
+  typedef testing::TestDllTransformTest Super;
+  typedef BlockGraph::Block::SourceRange SourceRange;
+
+  // Finds all blocks whose names appear in @p target_list, and writes the
+  // mapping fron name to block in @p result. Returns true iff all names in
+  // @p target_list are found.
+  static bool FindAllBlocks(
+      BlockGraph* block_graph,
+      const std::vector<std::string>& target_list,
+      std::map<std::string, BlockGraph::Block*>* result) {
+    DCHECK(result && result->empty());
+    std::set<std::string> name_set(target_list.begin(), target_list.end());
+    for (auto& it : block_graph->blocks_mutable()) {
+      std::string block_name = it.second.name();
+      if (name_set.find(block_name) != name_set.end()) {
+        (*result)[block_name] = &it.second;
+        name_set.erase(block_name);
+      }
+    }
+    return name_set.empty();
+  }
+
+  // Verifies that @p instructions contains all expected NOPs except for NOPs
+  // that would be inserted beyond the last instruction.
+  static void CheckNops(BasicBlock::Instructions* instructions) {
+    std::map<size_t, int> nop_indices;
+    size_t num_inst = FindAllNops(instructions, &nop_indices);
+    // The checks here depend on how NopSpec is initialized in
+    // FillerBasicBlockTransform.
+    EXPECT_TRUE(1 >= num_inst || nop_indices[1] == 1);
+  }
+
+  // Verifies that all contiguous NOPs in @p instuctions are followed by a
+  // non-NOP instruction, which shares the same source range as the NOP run.
+  static void CheckNopSourceRange(BasicBlock::Instructions* instructions) {
+    std::vector<SourceRange> range_queue;
+    BasicBlock::Instructions::iterator inst_it = instructions->begin();
+    for (; inst_it != instructions->end(); ++inst_it) {
+      if (!::strcmp(inst_it->GetName(), kNopName)) {
+        // Found NOP: add to queue.
+        range_queue.push_back(inst_it->source_range());
+      } else {
+        // Found non-NOP: verify stored ranges in the queue and then clear it.
+        for (SourceRange& nop_source_range : range_queue) {
+          EXPECT_EQ(inst_it->source_range(), nop_source_range);
+        }
+        range_queue.clear();
+      }
+    }
+    // Expect there's no trailing NOP.
+    EXPECT_TRUE(range_queue.empty());
+  }
+};
+
+}  // namespace
+
+// Sanity check for helper CreateInstructions().
+TEST_F(FillerBasicBlockTransformTest, CreateInstructions) {
+  for (int i = 0; i < 10; ++i) {
+    CreateInstructions(i);
+    size_t count = 0;
+    for (auto inst : *instructions_.get())
+      ++count;
+    EXPECT_EQ(i, count);
+  }
+}
+
+TEST_F(FillerBasicBlockTransformTest, InjectRegular) {
+  CreateInstructions(8);
+  NopSpec nop_spec = {
+    {1, NopSizes::NOP3},
+    {2, NopSizes::NOP1},
+    {3, NopSizes::NOP4},
+    {6, NopSizes::NOP1},
+    {8, NopSizes::NOP5},
+    {9, NopSizes::NOP9}};
+  FillerBasicBlockTransform::InjectNop(nop_spec, false, instructions_.get());
+  std::map<size_t, int> nop_indices;
+  EXPECT_EQ(8U + 6U, FindAllNops(instructions_.get(), &nop_indices));
+  EXPECT_EQ(6U, nop_indices.size());
+  EXPECT_EQ(3U, nop_indices[1]);
+  EXPECT_EQ(1U, nop_indices[2]);
+  EXPECT_EQ(4U, nop_indices[3]);
+  EXPECT_EQ(1U, nop_indices[6]);
+  EXPECT_EQ(5U, nop_indices[8]);
+  EXPECT_EQ(9U, nop_indices[9]);
+}
+
+TEST_F(FillerBasicBlockTransformTest, InjectToStart) {
+  CreateInstructions(5);
+  NopSpec nop_spec1 = {{0, NopSizes::NOP4}};
+  FillerBasicBlockTransform::InjectNop(nop_spec1, false, instructions_.get());
+  std::map<size_t, int> nop_indices1;
+  EXPECT_EQ(5U + 1U, FindAllNops(instructions_.get(), &nop_indices1));
+  EXPECT_EQ(1U, nop_indices1.size());
+  EXPECT_EQ(4U, nop_indices1[0]);
+
+  // Inject another NOP, when a NOP already exists.
+  NopSpec nop_spec2 = {{0, NopSizes::NOP1}};
+  FillerBasicBlockTransform::InjectNop(nop_spec2, false, instructions_.get());
+  std::map<size_t, int> nop_indices2;
+  EXPECT_EQ(5U + 1U + 1U, FindAllNops(instructions_.get(), &nop_indices2));
+  EXPECT_EQ(2U, nop_indices2.size());  // New + existing.
+  EXPECT_EQ(1U, nop_indices2[0]);  // From |nop_spec2|.
+  EXPECT_EQ(4U, nop_indices2[1]);  // From |nop_spec1|.
+}
+
+TEST_F(FillerBasicBlockTransformTest, InjectToBeforeEnd) {
+  CreateInstructions(7);
+  NopSpec nop_spec = {{6, NopSizes::NOP2}};
+  FillerBasicBlockTransform::InjectNop(nop_spec, false, instructions_.get());
+  std::map<size_t, int> nop_indices;
+  EXPECT_EQ(7U + 1U, FindAllNops(instructions_.get(), &nop_indices));
+  EXPECT_EQ(1U, nop_indices.size());
+  EXPECT_EQ(2U, nop_indices[6]);
+}
+
+TEST_F(FillerBasicBlockTransformTest, CannotInjectBeyondEnd) {
+  CreateInstructions(7);
+  NopSpec nop_spec = {{7, NopSizes::NOP1}, {17, NopSizes::NOP1}};
+  FillerBasicBlockTransform::InjectNop(nop_spec, false, instructions_.get());
+  std::map<size_t, int> nop_indices;
+  EXPECT_EQ(7U, FindAllNops(instructions_.get(), &nop_indices));
+  EXPECT_EQ(0U, nop_indices.size());
+}
+
+TEST_F(FillerBasicBlockTransformTest, InjectToEmpty) {
+  CreateInstructions(0);
+  NopSpec nop_spec = {{0, NopSizes::NOP1}, {1, NopSizes::NOP2}};
+  FillerBasicBlockTransform::InjectNop(nop_spec, false, instructions_.get());
+  std::map<size_t, int> nop_indices;
+  EXPECT_EQ(0U, FindAllNops(instructions_.get(), &nop_indices));
+  EXPECT_EQ(0U, nop_indices.size());
+}
+
+TEST_F(FillerBasicBlockTransformTest, InjectToSingle) {
+  CreateInstructions(1);
+  NopSpec nop_spec = {
+    {0, NopSizes::NOP5},
+    {1, NopSizes::NOP8},
+    {3, NopSizes::NOP2}};  // Gets ignored.
+  FillerBasicBlockTransform::InjectNop(nop_spec, false, instructions_.get());
+  std::map<size_t, int> nop_indices;
+  EXPECT_EQ(1U + 2U, FindAllNops(instructions_.get(), &nop_indices));
+  EXPECT_EQ(2U, nop_indices.size());
+  EXPECT_EQ(5U, nop_indices[0]);
+  EXPECT_EQ(8U, nop_indices[1]);
+}
+
+TEST_F(FillerBasicBlockTransformTest, InjectNone) {
+  CreateInstructions(7);
+  NopSpec nop_spec = {};
+  FillerBasicBlockTransform::InjectNop(nop_spec, false, instructions_.get());
+  std::map<size_t, int> nop_indices;
+  EXPECT_EQ(7U, FindAllNops(instructions_.get(), &nop_indices));
+  EXPECT_EQ(0U, nop_indices.size());
+}
+
+TEST_F(FillerBasicBlockTransformTest, InjectConsecutive) {
+  CreateInstructions(4);
+  NopSpec nop_spec = {
+      {0, NopSizes::NOP1},
+      {1, NopSizes::NOP2},
+      {2, NopSizes::NOP3},
+      {3, NopSizes::NOP5},
+      {4, NopSizes::NOP7},
+      {5, NopSizes::NOP11}};
+  FillerBasicBlockTransform::InjectNop(nop_spec, false, instructions_.get());
+  std::map<size_t, int> nop_indices;
+  EXPECT_EQ(4U + 6U, FindAllNops(instructions_.get(), &nop_indices));
+  EXPECT_EQ(6U, nop_indices.size());
+  EXPECT_EQ(1U, nop_indices[0]);
+  EXPECT_EQ(2U, nop_indices[1]);
+  EXPECT_EQ(3U, nop_indices[2]);
+  EXPECT_EQ(5U, nop_indices[3]);
+  EXPECT_EQ(7U, nop_indices[4]);
+  EXPECT_EQ(11U, nop_indices[5]);
+}
+
+TEST_F(FillerBasicBlockTransformTest, InjectAlternate) {
+  CreateInstructions(4);
+  NopSpec nop_spec = {
+      {0, NopSizes::NOP10},
+      {2, NopSizes::NOP9},
+      {4, NopSizes::NOP8},
+      {6, NopSizes::NOP7},
+      {8, NopSizes::NOP6},  // Gets ignored.
+      {10, NopSizes::NOP5}};  // Gets ignored.
+  FillerBasicBlockTransform::InjectNop(nop_spec, false, instructions_.get());
+  std::map<size_t, int> nop_indices;
+  EXPECT_EQ(4U + 4U, FindAllNops(instructions_.get(), &nop_indices));
+  EXPECT_EQ(4U, nop_indices.size());
+  EXPECT_EQ(10U, nop_indices[0]);
+  EXPECT_EQ(9U, nop_indices[2]);
+  EXPECT_EQ(8U, nop_indices[4]);
+  EXPECT_EQ(7U, nop_indices[6]);
+}
+
+TEST_F(FillerTransformTest, Apply) {
+  std::vector<std::string> target_list = {
+    "Used::M",
+    "TestUnusedFuncs"
+  };
+
+  ASSERT_NO_FATAL_FAILURE(DecomposeTestDll());
+
+  // Apply the transform.
+  TestFillerTransform tx(target_list);
+  tx.set_debug_friendly(true);  // Copy source ranges to injected NOPs.
+  ASSERT_TRUE(block_graph::ApplyBlockGraphTransform(
+      &tx, policy_, &block_graph_, header_block_));
+
+  // Check results. First find and store target blocks.
+  EXPECT_EQ(2U, tx.num_targets_updated());
+  std::map<std::string, BlockGraph::Block*> target_map;
+  ASSERT_TRUE(FindAllBlocks(&block_graph_, target_list, &target_map));
+  ASSERT_TRUE(target_map.size() == target_list.size());
+
+  // Check the block for each target.
+  for (auto& it : target_map) {
+    BlockGraph::Block* target_block = it.second;
+
+    // Decompose target block to subgraph.
+    block_graph::BasicBlockSubGraph subgraph;
+    block_graph::BasicBlockDecomposer bb_decomposer(target_block, &subgraph);
+    ASSERT_TRUE(bb_decomposer.Decompose());
+
+    // Examine each basic code block.
+    block_graph::BasicBlockSubGraph::BBCollection& basic_blocks =
+        subgraph.basic_blocks();
+    for (auto bb = basic_blocks.begin(); bb != basic_blocks.end(); ++bb) {
+      BasicCodeBlock* bc_block = BasicCodeBlock::Cast(*bb);
+      if (bc_block != nullptr) {
+        CheckNops(&bc_block->instructions());
+        CheckNopSourceRange(&bc_block->instructions());
+      }
+    }
+  }
+}
+
+}  // namespace transforms
+}  // namespace instrument