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 
25 using namespace llvm;
26 using namespace llvm::dxil;
27 
28 namespace {
29 class DXContainerGlobals : public llvm::ModulePass {
30 
31   GlobalVariable *getShaderFlags(Module &M);
32   GlobalVariable *computeShaderHash(Module &M);
33 
34 public:
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 
54 bool 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 
63 GlobalVariable *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 
76 GlobalVariable *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 
104 char DXContainerGlobals::ID = 0;
105 INITIALIZE_PASS_BEGIN(DXContainerGlobals, "dxil-globals",
106                       "DXContainer Global Emitter", false, true)
107 INITIALIZE_PASS_DEPENDENCY(ShaderFlagsAnalysisWrapper)
108 INITIALIZE_PASS_END(DXContainerGlobals, "dxil-globals",
109                     "DXContainer Global Emitter", false, true)
110 
111 ModulePass *llvm::createDXContainerGlobalsPass() {
112   return new DXContainerGlobals();
113 }
114