Spv Opt

// source/opt/my_pass.h
#ifndef SOURCE_OPT_MY_PASS_H_
#define SOURCE_OPT_MY_PASS_H_
#include "source/opt/pass.h"
namespace spvtools::opt {
class MyPass : public Pass {
 public:
  const char* name() const override { return "my-pass"; }
  Status Process() override;
  IRContext::Analysis GetPreservedAnalyses() override {
    return IRContext::kAnalysisDefUse | IRContext::kAnalysisCFG;
  }
};
}  // namespace spvtools::opt
#endif

// source/opt/my_pass.cpp
#include "source/opt/my_pass.h"
namespace spvtools::opt {
Pass::Status MyPass::Process() {
  bool modified = false;
  // Iterate functions
  for (auto& func : *get_module()) {
    for (auto& block : func) {
      for (auto& inst : block) {
        // transform inst...
        modified = true;
      }
    }
  }
  return modified ? Status::SuccessWithChange : Status::SuccessWithoutChange;
}
}  // namespace spvtools::opt

#include "source/opt/mem_pass.h"
class MyMemPass : public MemPass {
  // Inherits helpers: GetPtr(), IsTargetVar(), CollectTargetVars(),
  // HasOnlyNamesAndDecorates(), KillAllInsts(), Type2Undef(), etc.
};

Module* m = get_module();           // or context()->module()
IRContext* ctx = context();

m->ForEachInst([](Instruction* inst){ /* all insts */ }, true);
ctx->get_def_use_mgr();             // analysis::DefUseManager
ctx->get_type_mgr();                // analysis::TypeManager
ctx->get_constant_mgr();            // analysis::ConstantManager
ctx->get_decoration_mgr();          // analysis::DecorationManager
ctx->cfg();                         // CFG
ctx->GetValueNumberTable();         // ValueNumberTable
ctx->GetStructuredCFGAnalysis();    // StructuredCFGAnalysis
ctx->InvalidateAnalyses(IRContext::kAnalysisDefUse | IRContext::kAnalysisCFG);
ctx->IsConsistent();                // debug invariant check

spv::Op opcode = inst->opcode();
uint32_t rid = inst->result_id();   // 0 if none
uint32_t tid = inst->type_id();     // 0 if none

// Operands: inst->begin() .. inst->end()
for (auto& op : *inst) {
  if (spvIsIdType(op.type)) { uint32_t id = op.words[0]; }
}

uint32_t val = inst->GetSingleWordInOperand(idx);
inst->NumInOperands();
inst->SetResultId(new_id);
inst->SetResultType(new_type_id);
inst->SetInOperand(idx, {new_val});
inst->ToBinary(&words);

// Predicates
inst->IsBranch();
inst->IsBlockTerminator();
inst->IsDecoration();
inst->IsConstant();
inst->IsLoad();
inst->IsNop();
inst->ToNop();        // turns instruction into OpNop

for (auto& block : func) {  // func is a Function&
  uint32_t label = block.id();
  Instruction* label_inst = block.GetLabelInst();
  Instruction* merge = block.GetMergeInst();       // OpSelectionMerge / OpLoopMerge
  Instruction* loop_merge = block.GetLoopMergeInst();
  bool has_phi = block.HasPhiInstructions();

  // Iterate instructions (label included if you use ForEachInst)
  for (auto& inst : block) { }
  block.ForEachInst([](Instruction* i){ }, true);  // true = include debug lines

  // Terminator helpers
  block.ForEachSuccessorLabels([](uint32_t id){ });
  bool is_loop_header = block.IsLoopHeader();
  uint32_t merge_id = block.MergeBlockIdIfAny();
  uint32_t continue_id = block.ContinueBlockIdIfAny();
  Instruction* term = block.terminator();
}

for (auto& func : *get_module()) {
  uint32_t func_id = func->DefInst().result_id();
  bool is_declaration = func->IsDeclaration();
  func->ForEachParam([](Instruction* param){ });
  // iterate blocks (func is a Function& from the module loop)
  for (auto& block : func) { }
}

bool IsEntryPoint(Function* func, Module* module) {
  for (auto& entry : module->entry_points()) {
    // OpEntryPoint: operand 0 = execution model, operand 1 = function id
    if (entry.GetSingleWordInOperand(1) == func->result_id()) return true;
  }
  return false;
}

#include "source/opt/ir_builder.h"

// Insert before an instruction
InstructionBuilder b(context(), insertion_point,
  IRContext::kAnalysisInstrToBlockMapping | IRContext::kAnalysisDefUse);

// Or append to end of a block
InstructionBuilder b(context(), parent_block,
  IRContext::kAnalysisInstrToBlockMapping | IRContext::kAnalysisDefUse);

Instruction* add = b.AddBinaryOp(type_id, spv::Op::OpIAdd, lhs, rhs);
Instruction* extract = b.AddCompositeExtract(elem_type_id, composite_id, {idx0, idx1});
Instruction* construct = b.AddCompositeConstruct(type_id, {id0, id1});
Instruction* load = b.AddLoad(type_id, ptr_id);
Instruction* store = b.AddStore(ptr_id, value_id);
Instruction* branch = b.AddBranch(target_id);
Instruction* cbranch = b.AddConditionalBranch(cond_id, true_id, false_id);
Instruction* cbranch_with_merge = b.AddConditionalBranch(cond_id, true_id, false_id, merge_id);
Instruction* phi = b.AddPhi(type_id, {val0, block0, val1, block1});
Instruction* unary = b.AddUnaryOp(type_id, spv::Op::OpConvertFToS, operand);
Instruction* nullary = b.AddNullaryOp(type_id, spv::Op::OpGroupAll);
Instruction* select = b.AddSelect(type_id, cond_id, true_id, false_id);
Instruction* access = b.AddAccessChain(ptr_type_id, base_ptr_id, {idx_id0, idx_id1});
Instruction* var = b.AddVariable(ptr_type_id, static_cast<uint32_t>(spv::StorageClass::Function));

// Replace all uses of old_id with new_id
ctx->ReplaceAllUsesWith(old_id, new_id);

// Replace uses only when predicate returns true
ctx->ReplaceAllUsesWithPredicate(old_id, new_id, [](Instruction* user) {
  return user->opcode() == spv::Op::OpStore;
});

// Kill an instruction (removes from block, updates def-use)
ctx->KillInst(inst);

// Kill an id and all its uses
ctx->KillDef(id);

// Get the defining instruction for an id
Instruction* def = ctx->get_def_use_mgr()->GetDef(id);

// Get users of an id
ctx->get_def_use_mgr()->ForEachUser(id, [](Instruction* user){ });
uint32_t n = ctx->get_def_use_mgr()->NumUsers(id);

std::vector<Instruction*> to_kill;
get_module()->ForEachInst([&](Instruction* inst) {
  if (inst->IsNop()) to_kill.push_back(inst);
}, false);
for (auto* inst : to_kill) context()->KillInst(inst);

if (inst->opcode() == spv::Op::OpPhi) {
  for (uint32_t i = 0; i + 1 < inst->NumInOperands(); i += 2) {
    uint32_t value = inst->GetSingleWordInOperand(i);
    uint32_t parent = inst->GetSingleWordInOperand(i + 1);
  }
}

#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "test/opt/pass_fixture.h"
#include "test/opt/pass_utils.h"
#include "source/opt/my_pass.h"

using MyPassTest = PassTest<::testing::Test>;

TEST_F(MyPassTest, Basic) {
  const std::string before = R"(
OpCapability Shader
OpMemoryModel Logical GLSL450
%void = OpTypeVoid
%main = OpFunction %void None %void
%entry = OpLabel
OpReturn
OpFunctionEnd
)";
  const std::string after = before;
  SinglePassRunAndCheck<MyPass>(before, after, /*skip_nop=*/false, /*do_validation=*/false);
}

const std::string assembly = R"(
; CHECK: OpReturn
OpCapability Shader
OpMemoryModel Logical GLSL450
%void = OpTypeVoid
%main = OpFunction %void None %void
%entry = OpLabel
OpReturn
OpFunctionEnd
)";
SinglePassRunAndMatch<MyPass>(assembly, false);

TEST_F(MyPassTest, Pipeline) {
  const std::string before = R"(... )";
  const std::string after = R"(... )";
  AddPass<MyFirstPass>();
  AddPass<MySecondPass>();
  RunAndCheck(before, after);
}

#include "source/opt/build_module.h"

TEST(MyPass, Manual) {
  std::unique_ptr<IRContext> ctx =
    BuildModule(SPV_ENV_UNIVERSAL_1_3, nullptr, assembly,
                SPV_TEXT_TO_BINARY_OPTION_PRESERVE_NUMERIC_IDS);
  ASSERT_NE(ctx, nullptr);
  MyPass pass;
  auto status = pass.Run(ctx.get());
  EXPECT_EQ(status, Pass::Status::SuccessWithChange);
  EXPECT_TRUE(ctx->IsConsistent());
}

Optimizer::PassToken CreateMyPassPass();

Optimizer::PassToken CreateMyPassPass() {
  return MakeUnique<Optimizer::PassToken::Impl>(MakeUnique<opt::MyPass>());
}

} else if (pass_name == "my-pass") {
  RegisterPass(CreateMyPassPass());

  my_pass.h
  ...
  my_pass.cpp