1//===- DXContainerGlobals.cpp - DXContainer global generator pass ---------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// DXContainerGlobalsPass implementation.
10//
11//===----------------------------------------------------------------------===//
12
13#include "DXILShaderFlags.h"
14#include "DirectX.h"
15#include "llvm/ADT/StringExtras.h"
16#include "llvm/ADT/StringRef.h"
17#include "llvm/BinaryFormat/DXContainer.h"
18#include "llvm/CodeGen/Passes.h"
19#include "llvm/IR/Constants.h"
20#include "llvm/InitializePasses.h"
21#include "llvm/Pass.h"
22#include "llvm/Support/MD5.h"
23#include "llvm/Transforms/Utils/ModuleUtils.h"
24
25using namespace llvm;
26using namespace llvm::dxil;
27
28namespace {
29class DXContainerGlobals : public llvm::ModulePass {
30
31  GlobalVariable *getShaderFlags(Module &M);
32  GlobalVariable *computeShaderHash(Module &M);
33
34public:
35  static char ID; // Pass identification, replacement for typeid
36  DXContainerGlobals() : ModulePass(ID) {
37    initializeDXContainerGlobalsPass(*PassRegistry::getPassRegistry());
38  }
39
40  StringRef getPassName() const override {
41    return "DXContainer Global Emitter";
42  }
43
44  bool runOnModule(Module &M) override;
45
46  void getAnalysisUsage(AnalysisUsage &AU) const override {
47    AU.setPreservesAll();
48    AU.addRequired<ShaderFlagsAnalysisWrapper>();
49  }
50};
51
52} // namespace
53
54bool DXContainerGlobals::runOnModule(Module &M) {
55  llvm::SmallVector<GlobalValue *> Globals;
56  Globals.push_back(getShaderFlags(M));
57  Globals.push_back(computeShaderHash(M));
58
59  appendToCompilerUsed(M, Globals);
60  return true;
61}
62
63GlobalVariable *DXContainerGlobals::getShaderFlags(Module &M) {
64  const uint64_t Flags =
65      (uint64_t)(getAnalysis<ShaderFlagsAnalysisWrapper>().getShaderFlags());
66
67  Constant *FlagsConstant = ConstantInt::get(M.getContext(), APInt(64, Flags));
68  auto *GV = new llvm::GlobalVariable(M, FlagsConstant->getType(), true,
69                                      GlobalValue::PrivateLinkage,
70                                      FlagsConstant, "dx.sfi0");
71  GV->setSection("SFI0");
72  GV->setAlignment(Align(4));
73  return GV;
74}
75
76GlobalVariable *DXContainerGlobals::computeShaderHash(Module &M) {
77  auto *DXILConstant =
78      cast<ConstantDataArray>(M.getNamedGlobal("dx.dxil")->getInitializer());
79  MD5 Digest;
80  Digest.update(DXILConstant->getRawDataValues());
81  MD5::MD5Result Result = Digest.final();
82
83  dxbc::ShaderHash HashData = {0, {0}};
84  // The Hash's IncludesSource flag gets set whenever the hashed shader includes
85  // debug information.
86  if (M.debug_compile_units_begin() != M.debug_compile_units_end())
87    HashData.Flags = static_cast<uint32_t>(dxbc::HashFlags::IncludesSource);
88
89  memcpy(reinterpret_cast<void *>(&HashData.Digest), Result.data(), 16);
90  if (sys::IsBigEndianHost)
91    HashData.swapBytes();
92  StringRef Data(reinterpret_cast<char *>(&HashData), sizeof(dxbc::ShaderHash));
93
94  Constant *ModuleConstant =
95      ConstantDataArray::get(M.getContext(), arrayRefFromStringRef(Data));
96  auto *GV = new llvm::GlobalVariable(M, ModuleConstant->getType(), true,
97                                      GlobalValue::PrivateLinkage,
98                                      ModuleConstant, "dx.hash");
99  GV->setSection("HASH");
100  GV->setAlignment(Align(4));
101  return GV;
102}
103
104char DXContainerGlobals::ID = 0;
105INITIALIZE_PASS_BEGIN(DXContainerGlobals, "dxil-globals",
106                      "DXContainer Global Emitter", false, true)
107INITIALIZE_PASS_DEPENDENCY(ShaderFlagsAnalysisWrapper)
108INITIALIZE_PASS_END(DXContainerGlobals, "dxil-globals",
109                    "DXContainer Global Emitter", false, true)
110
111ModulePass *llvm::createDXContainerGlobalsPass() {
112  return new DXContainerGlobals();
113}
114