[Syzygy Instrumenter] Add FillerTransform.

syzygy/instrument/transforms/filler_transform.h

+// 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.
+//
+// Declaration of the filler instrumentation transform. This instruments a given
+// list of functions by injecting NOP fillers at various places.
+
+#ifndef SYZYGY_INSTRUMENT_TRANSFORMS_FILLER_TRANSFORM_H_
+#define SYZYGY_INSTRUMENT_TRANSFORMS_FILLER_TRANSFORM_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/files/file_path.h"
+#include "syzygy/block_graph/basic_block.h"
+#include "syzygy/block_graph/block_graph.h"
+#include "syzygy/block_graph/transforms/iterative_transform.h"
+#include "syzygy/block_graph/transforms/named_transform.h"
+
+using block_graph::TransformPolicyInterface;
+
+namespace instrument {
+namespace transforms {
+
+// A class to transform subgraph by injecting NOP fillers to basic code blocks.
+class FillerBasicBlockTransform
+    : public block_graph::transforms::NamedBasicBlockSubGraphTransformImpl<
+          FillerBasicBlockTransform> {
+ public:
+  typedef block_graph::BasicBlock BasicBlock;
+  typedef block_graph::BasicBlockSubGraph BasicBlockSubGraph;
+  typedef block_graph::BasicCodeBlock BasicCodeBlock;
+  typedef block_graph::BlockGraph BlockGraph;
+  typedef block_graph::TransformPolicyInterface TransformPolicyInterface;
+  typedef BlockGraph::Block Block;
+
+  // NOP sizes that can be realized with a single instruction. We disallow
+  // multi-instruction NOPs to ensure consistent instruction indexes after NOP
+  // injection.
+  enum NopSizes {
+    NOP1 = 1,
+    NOP2,
+    NOP3,
+    NOP4,
+    NOP5,
+    NOP6,
+    NOP7,
+    NOP8,
+    NOP9,
+    NOP10,
+    NOP11,
+  };
+
+  // A map from instruction indices to NOP sizes. For example,
+  // {1: NOP3, 3: NOP2, 4: NOP5} specifies a transformation that takes
+  // instruction sequence "ABCDE" to "AXBYZCDE", where "X" is the 3-byte NOP,
+  // "Y" is the 2-byte NOP, and "Z" is the 5-byte NOP.
+  typedef const std::map<size_t, NopSizes> NopSpec;
+
+  FillerBasicBlockTransform()
+      : debug_friendly_(false) { }
+  virtual ~FillerBasicBlockTransform() { }
+
+  // For NamedBlockGraphTransformImpl.
+  static const char kTransformName[];
+
+  // @name Accessors and mutators.
+  // @{
+  bool debug_friendly() const { return debug_friendly_; }
+  void set_debug_friendly(bool flag) { debug_friendly_ = flag; }
+  // @}
+
+  // Injects NOP into @p instruction. @p nop_spec specifies post-injection
+  // instruction indices and sizes of NOPs. We do not inject beyond the last
+  // instruction.
+  static void InjectNop(const NopSpec& nop_spec,
+                        bool debug_friendly,
+                        BasicBlock::Instructions* instructions);
+
+  // @name BasicBlockSubGraphTransformInterface implementation.
+  // @{
+  // Applies the filler transform. Specifically, visits every basic code block
+  // in @p basic_block_subgraph and injects NOP at various places.
+  bool TransformBasicBlockSubGraph(
+      const TransformPolicyInterface* policy,
+      BlockGraph* block_graph,
+      BasicBlockSubGraph* basic_block_subgraph) override;
+  // @}
+
+ private:
+  // Activate the overwriting of source range for created instructions.
+  bool debug_friendly_;
+
+  DISALLOW_COPY_AND_ASSIGN(FillerBasicBlockTransform);
+};
+
+// A class to apply filler transform, which injects NOPs to basic code blocks
+// in a given list of decorated function names.
+class FillerTransform
+    : public block_graph::transforms::IterativeTransformImpl<FillerTransform> {
+ public:
+  typedef block_graph::BasicBlockSubGraph BasicBlockSubGraph;
+  typedef block_graph::BlockGraph BlockGraph;
+  typedef BlockGraph::Block Block;
+
+  explicit FillerTransform(const std::vector<std::string>& target_list);
+  virtual ~FillerTransform() { }
+
+  // Accessors
+  // @{
+  size_t num_targets_updated() const { return num_targets_updated_; }
+  // @}
+
+  // For NamedBlockGraphTransformImpl.
+  static const char kTransformName[];
+
+  // @name Accessors and mutators.
+  // @{
+  bool debug_friendly() const { return debug_friendly_; }
+  void set_debug_friendly(bool flag) { debug_friendly_ = flag; }
+  // @}
+
+ protected:
+  // Returns whether @p block is a target.
+  bool ShouldProcessBlock(Block* block) const;
+
+  // Verifies that all targets were found, and displays warning if not.
+  void CheckAllTargetsFound() const;
+
+  // @name IterativeTransformImpl implementation.
+  // @{
+  bool PreBlockGraphIteration(const TransformPolicyInterface* policy,
+                              BlockGraph* block_graph,
+                              Block* header_block);
+  bool OnBlock(const TransformPolicyInterface* policy,
+               BlockGraph* block_graph,
+               Block* block);
+  bool PostBlockGraphIteration(const TransformPolicyInterface* policy,
+                               BlockGraph* block_graph,
+                               Block* header_block);
+  // @}
+
+ private:
+  friend NamedBlockGraphTransformImpl<FillerTransform>;
+  friend IterativeTransformImpl<FillerTransform>;
+
+  // Activate the overwriting of source range for created instructions.
+  bool debug_friendly_;
+
+  // Names of targets, maps to whether the target was seen.
+  std::map<std::string, bool> target_names_;
+
+  // Counters used by CheckAllTargetsFound.
+  // @{
+  size_t num_blocks_;
+  size_t num_code_blocks_;
+  size_t num_targets_updated_;
+  // @}
+
+  DISALLOW_COPY_AND_ASSIGN(FillerTransform);
+};
+
+}  // namespace transforms
+}  // namespace instrument
+
+#endif  // SYZYGY_INSTRUMENT_TRANSFORMS_FILLER_TRANSFORM_H_