SPIRV-Tools/source/opt/inline_opaque_pass.cpp
Steven Perron 2d2a512691
Don't inline recursive functions. (#2130)
* Move ProcessFunction* function from pass to the context.

There are a few functions that are used to traverse the call tree.
They currently live in the Pass class, but they have nothing to do with
a pass, and may be needed outside of a pass.  They would be better in
the ir context, or in a specific call tree class if we ever have a need
for it.

* Don't inline recursive functions.

Inlining does not check if a function is recursive or not.  This has
been fine as long as the shader was a Vulkan shader, which forbid
recursive functions.  However, not all shaders are vulkan, so either
we limit inlining to Vulkan shaders or we teach it to look for recursive
functions.

I prefer to keep the passes as general as is reasonable.  The change
does not require much new code in inlining and gives a reason to refactor
some other code.

The changes are to add a member function to the Function class that
checks if that function is recursive or not.

Then this is used in inlining to not inlining a function call if it calls
a recursive function.

* Add id to function analysis

There are a few places that build a map from ids to Function whose
result is that id.  I decided to add an analysis to the context for this
to reduce that code, and simplify some of the functions.

* Add missing file.
2018-11-29 14:24:58 -05:00

114 lines
3.7 KiB
C++

// Copyright (c) 2017 The Khronos Group Inc.
// Copyright (c) 2017 Valve Corporation
// Copyright (c) 2017 LunarG Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "source/opt/inline_opaque_pass.h"
#include <utility>
namespace spvtools {
namespace opt {
namespace {
const uint32_t kTypePointerTypeIdInIdx = 1;
} // anonymous namespace
bool InlineOpaquePass::IsOpaqueType(uint32_t typeId) {
const Instruction* typeInst = get_def_use_mgr()->GetDef(typeId);
switch (typeInst->opcode()) {
case SpvOpTypeSampler:
case SpvOpTypeImage:
case SpvOpTypeSampledImage:
return true;
case SpvOpTypePointer:
return IsOpaqueType(
typeInst->GetSingleWordInOperand(kTypePointerTypeIdInIdx));
default:
break;
}
// TODO(greg-lunarg): Handle arrays containing opaque type
if (typeInst->opcode() != SpvOpTypeStruct) return false;
// Return true if any member is opaque
return !typeInst->WhileEachInId([this](const uint32_t* tid) {
if (IsOpaqueType(*tid)) return false;
return true;
});
}
bool InlineOpaquePass::HasOpaqueArgsOrReturn(const Instruction* callInst) {
// Check return type
if (IsOpaqueType(callInst->type_id())) return true;
// Check args
int icnt = 0;
return !callInst->WhileEachInId([&icnt, this](const uint32_t* iid) {
if (icnt > 0) {
const Instruction* argInst = get_def_use_mgr()->GetDef(*iid);
if (IsOpaqueType(argInst->type_id())) return false;
}
++icnt;
return true;
});
}
bool InlineOpaquePass::InlineOpaque(Function* func) {
bool modified = false;
// Using block iterators here because of block erasures and insertions.
for (auto bi = func->begin(); bi != func->end(); ++bi) {
for (auto ii = bi->begin(); ii != bi->end();) {
if (IsInlinableFunctionCall(&*ii) && HasOpaqueArgsOrReturn(&*ii)) {
// Inline call.
std::vector<std::unique_ptr<BasicBlock>> newBlocks;
std::vector<std::unique_ptr<Instruction>> newVars;
GenInlineCode(&newBlocks, &newVars, ii, bi);
// If call block is replaced with more than one block, point
// succeeding phis at new last block.
if (newBlocks.size() > 1) UpdateSucceedingPhis(newBlocks);
// Replace old calling block with new block(s).
bi = bi.Erase();
bi = bi.InsertBefore(&newBlocks);
// Insert new function variables.
if (newVars.size() > 0)
func->begin()->begin().InsertBefore(std::move(newVars));
// Restart inlining at beginning of calling block.
ii = bi->begin();
modified = true;
} else {
++ii;
}
}
}
return modified;
}
void InlineOpaquePass::Initialize() { InitializeInline(); }
Pass::Status InlineOpaquePass::ProcessImpl() {
// Do opaque inlining on each function in entry point call tree
ProcessFunction pfn = [this](Function* fp) { return InlineOpaque(fp); };
bool modified = context()->ProcessEntryPointCallTree(pfn);
return modified ? Status::SuccessWithChange : Status::SuccessWithoutChange;
}
InlineOpaquePass::InlineOpaquePass() = default;
Pass::Status InlineOpaquePass::Process() {
Initialize();
return ProcessImpl();
}
} // namespace opt
} // namespace spvtools