1// Copyright (c) 2016 Google Inc.
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#include "source/opt/strip_debug_info_pass.h"
16#include "source/opt/ir_context.h"
17
18namespace spvtools {
19namespace opt {
20
21Pass::Status StripDebugInfoPass::Process() {
22 bool uses_non_semantic_info = false;
23 for (auto& inst : context()->module()->extensions()) {
24 const char* ext_name =
25 reinterpret_cast<const char*>(&inst.GetInOperand(0).words[0]);
26 if (0 == std::strcmp(ext_name, "SPV_KHR_non_semantic_info")) {
27 uses_non_semantic_info = true;
28 }
29 }
30
31 std::vector<Instruction*> to_kill;
32
33 // if we use non-semantic info, it may reference OpString. Do a more
34 // expensive pass checking the uses of the OpString to see if any are
35 // OpExtInst on a non-semantic instruction set. If we're not using the
36 // extension then we can do a simpler pass and kill all debug1 instructions
37 if (uses_non_semantic_info) {
38 for (auto& inst : context()->module()->debugs1()) {
39 switch (inst.opcode()) {
40 case SpvOpString: {
41 analysis::DefUseManager* def_use = context()->get_def_use_mgr();
42
43 // see if this string is used anywhere by a non-semantic instruction
44 bool no_nonsemantic_use =
45 def_use->WhileEachUser(&inst, [def_use](Instruction* use) {
46 if (use->opcode() == SpvOpExtInst) {
47 auto ext_inst_set =
48 def_use->GetDef(use->GetSingleWordInOperand(0u));
49 const char* extension_name = reinterpret_cast<const char*>(
50 &ext_inst_set->GetInOperand(0).words[0]);
51 if (0 == std::strncmp(extension_name, "NonSemantic.", 12)) {
52 // found a non-semantic use, return false as we cannot
53 // remove this OpString
54 return false;
55 }
56 }
57
58 // other instructions can't be a non-semantic use
59 return true;
60 });
61
62 if (no_nonsemantic_use) to_kill.push_back(&inst);
63
64 break;
65 }
66
67 default:
68 to_kill.push_back(&inst);
69 break;
70 }
71 }
72 } else {
73 for (auto& dbg : context()->debugs1()) to_kill.push_back(&dbg);
74 }
75
76 for (auto& dbg : context()->debugs2()) to_kill.push_back(&dbg);
77 for (auto& dbg : context()->debugs3()) to_kill.push_back(&dbg);
78 for (auto& dbg : context()->ext_inst_debuginfo()) to_kill.push_back(&dbg);
79
80 // OpName must come first, since they may refer to other debug instructions.
81 // If they are after the instructions that refer to, then they will be killed
82 // when that instruction is killed, which will lead to a double kill.
83 std::sort(to_kill.begin(), to_kill.end(),
84 [](Instruction* lhs, Instruction* rhs) -> bool {
85 if (lhs->opcode() == SpvOpName && rhs->opcode() != SpvOpName)
86 return true;
87 return false;
88 });
89
90 bool modified = !to_kill.empty();
91
92 for (auto* inst : to_kill) context()->KillInst(inst);
93
94 // clear OpLine information
95 context()->module()->ForEachInst([&modified](Instruction* inst) {
96 modified |= !inst->dbg_line_insts().empty();
97 inst->dbg_line_insts().clear();
98 });
99
100 if (!get_module()->trailing_dbg_line_info().empty()) {
101 modified = true;
102 get_module()->trailing_dbg_line_info().clear();
103 }
104
105 return modified ? Status::SuccessWithChange : Status::SuccessWithoutChange;
106}
107
108} // namespace opt
109} // namespace spvtools
110