1 // Copyright (c) 2019 Google LLC
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //     http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #ifndef SOURCE_FUZZ_FUZZER_PASS_DONATE_MODULES_H_
16 #define SOURCE_FUZZ_FUZZER_PASS_DONATE_MODULES_H_
17 
18 #include <vector>
19 
20 #include "source/fuzz/fuzzer_pass.h"
21 #include "source/fuzz/fuzzer_util.h"
22 
23 namespace spvtools {
24 namespace fuzz {
25 
26 // A fuzzer pass that randomly adds code from other SPIR-V modules to the module
27 // being transformed.
28 class FuzzerPassDonateModules : public FuzzerPass {
29  public:
30   FuzzerPassDonateModules(
31       opt::IRContext* ir_context, TransformationContext* transformation_context,
32       FuzzerContext* fuzzer_context,
33       protobufs::TransformationSequence* transformations,
34       const std::vector<fuzzerutil::ModuleSupplier>& donor_suppliers);
35 
36   ~FuzzerPassDonateModules();
37 
38   void Apply() override;
39 
40   // Donates the global declarations and functions of |donor_ir_context| into
41   // the fuzzer pass's IR context.  |make_livesafe| dictates whether the
42   // functions of the donated module will be made livesafe (see
43   // FactFunctionIsLivesafe).
44   void DonateSingleModule(opt::IRContext* donor_ir_context, bool make_livesafe);
45 
46  private:
47   // Adapts a storage class coming from a donor module so that it will work
48   // in a recipient module, e.g. by changing Uniform to Private.
49   static SpvStorageClass AdaptStorageClass(SpvStorageClass donor_storage_class);
50 
51   // Identifies all external instruction set imports in |donor_ir_context| and
52   // populates |original_id_to_donated_id| with a mapping from the donor's id
53   // for such an import to a corresponding import in the recipient.  Aborts if
54   // no such corresponding import is available.
55   void HandleExternalInstructionImports(
56       opt::IRContext* donor_ir_context,
57       std::map<uint32_t, uint32_t>* original_id_to_donated_id);
58 
59   // Considers all types, globals, constants and undefs in |donor_ir_context|.
60   // For each instruction, uses |original_to_donated_id| to map its result id to
61   // either (1) the id of an existing identical instruction in the recipient, or
62   // (2) to a fresh id, in which case the instruction is also added to the
63   // recipient (with any operand ids that it uses being remapped via
64   // |original_id_to_donated_id|).
65   void HandleTypesAndValues(
66       opt::IRContext* donor_ir_context,
67       std::map<uint32_t, uint32_t>* original_id_to_donated_id);
68 
69   // Helper method for HandleTypesAndValues, to handle a single type/value.
70   void HandleTypeOrValue(
71       const opt::Instruction& type_or_value,
72       std::map<uint32_t, uint32_t>* original_id_to_donated_id);
73 
74   // Assumes that |donor_ir_context| does not exhibit recursion.  Considers the
75   // functions in |donor_ir_context|'s call graph in a reverse-topologically-
76   // sorted order (leaves-to-root), adding each function to the recipient
77   // module, rewritten to use fresh ids and using |original_id_to_donated_id| to
78   // remap ids.  The |make_livesafe| argument captures whether the functions in
79   // the module are required to be made livesafe before being added to the
80   // recipient.
81   void HandleFunctions(opt::IRContext* donor_ir_context,
82                        std::map<uint32_t, uint32_t>* original_id_to_donated_id,
83                        bool make_livesafe);
84 
85   // During donation we will have to ignore some instructions, e.g. because they
86   // use opcodes that we cannot support or because they reference the ids of
87   // instructions that have not been donated.  This function encapsulates the
88   // logic for deciding which whether instruction |instruction| from
89   // |donor_ir_context| can be donated.
90   bool CanDonateInstruction(
91       opt::IRContext* donor_ir_context, const opt::Instruction& instruction,
92       const std::map<uint32_t, uint32_t>& original_id_to_donated_id,
93       const std::set<uint32_t>& skipped_instructions) const;
94 
95   // We treat the OpArrayLength instruction specially.  In the donor shader this
96   // instruction yields the length of a runtime array that is the final member
97   // of a struct.  During donation, we will have converted the runtime array
98   // type, and the associated struct field, into a fixed-size array.
99   //
100   // Instead of donating this instruction, we turn it into an OpCopyObject
101   // instruction that copies the size of the fixed-size array.
102   void HandleOpArrayLength(
103       const opt::Instruction& instruction,
104       std::map<uint32_t, uint32_t>* original_id_to_donated_id,
105       std::vector<protobufs::Instruction>* donated_instructions) const;
106 
107   // The instruction |instruction| is required to be an instruction that cannot
108   // be easily donated, either because it uses an unsupported opcode, has an
109   // unsupported result type, or uses id operands that could not be donated.
110   //
111   // If |instruction| generates a result id, the function attempts to add a
112   // substitute for |instruction| to |donated_instructions| that has the correct
113   // result type.  If this cannot be done, the instruction's result id is added
114   // to |skipped_instructions|.  The mapping from donor ids to recipient ids is
115   // managed by |original_id_to_donated_id|.
116   void HandleDifficultInstruction(
117       const opt::Instruction& instruction,
118       std::map<uint32_t, uint32_t>* original_id_to_donated_id,
119       std::vector<protobufs::Instruction>* donated_instructions,
120       std::set<uint32_t>* skipped_instructions);
121 
122   // Adds an instruction based in |instruction| to |donated_instructions| in a
123   // form ready for donation.  The original instruction comes from
124   // |donor_ir_context|, and |original_id_to_donated_id| maps ids from
125   // |donor_ir_context| to corresponding ids in the recipient module.
126   void PrepareInstructionForDonation(
127       const opt::Instruction& instruction, opt::IRContext* donor_ir_context,
128       std::map<uint32_t, uint32_t>* original_id_to_donated_id,
129       std::vector<protobufs::Instruction>* donated_instructions);
130 
131   // Tries to create a protobufs::LoopLimiterInfo given a loop header basic
132   // block. Returns true if successful and outputs loop limiter into the |out|
133   // variable. Otherwise, returns false. |out| contains an undefined value when
134   // this function returns false.
135   bool CreateLoopLimiterInfo(
136       opt::IRContext* donor_ir_context, const opt::BasicBlock& loop_header,
137       const std::map<uint32_t, uint32_t>& original_id_to_donated_id,
138       protobufs::LoopLimiterInfo* out);
139 
140   // Requires that |donated_instructions| represents a prepared version of the
141   // instructions of |function_to_donate| (which comes from |donor_ir_context|)
142   // ready for donation, and |original_id_to_donated_id| maps ids from
143   // |donor_ir_context| to their corresponding ids in the recipient module.
144   //
145   // Attempts to add a livesafe version of the function, based on
146   // |donated_instructions|, to the recipient module. Returns true if the
147   // donation was successful, false otherwise.
148   bool MaybeAddLivesafeFunction(
149       const opt::Function& function_to_donate, opt::IRContext* donor_ir_context,
150       const std::map<uint32_t, uint32_t>& original_id_to_donated_id,
151       const std::vector<protobufs::Instruction>& donated_instructions);
152 
153   // Returns true if and only if |instruction| is a scalar, vector, matrix,
154   // array or struct; i.e. it is not an opaque type.
155   bool IsBasicType(const opt::Instruction& instruction) const;
156 
157   // Functions that supply SPIR-V modules
158   std::vector<fuzzerutil::ModuleSupplier> donor_suppliers_;
159 };
160 
161 }  // namespace fuzz
162 }  // namespace spvtools
163 
164 #endif  // SOURCE_FUZZ_FUZZER_PASS_DONATE_MODULES_H_
165