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#include "slang-ir-specialize-stage-switch.h"
#include "slang-capability.h"
#include "slang-compiler.h"
#include "slang-ir-call-graph.h"
#include "slang-ir-insts.h"
#include "slang-ir-util.h"
#include "slang-ir.h"
namespace Slang
{
bool funcHasGetCurrentStageInst(IRGlobalValueWithCode* func)
{
for (auto block : func->getBlocks())
{
for (auto inst : block->getChildren())
{
if (inst->getOp() == kIROp_GetCurrentStage)
{
return true;
}
}
}
return false;
}
void discoverStageSpecificFunctions(HashSet<IRInst*>& stageSpecificFunctions, IRModule* module)
{
List<IRInst*> workList;
for (auto inst : module->getGlobalInsts())
{
if (auto func = as<IRGlobalValueWithCode>(inst))
{
if (funcHasGetCurrentStageInst(func))
{
workList.add(inst);
stageSpecificFunctions.add(func);
}
}
}
for (Index i = 0; i < workList.getCount(); i++)
{
auto callee = workList[i];
traverseUses(
callee,
[&](IRUse* use)
{
if (use->getUser()->getOp() == kIROp_Call)
{
auto parentFunc = getParentFunc(use->getUser());
if (parentFunc && stageSpecificFunctions.add(parentFunc))
{
workList.add(parentFunc);
}
}
});
}
}
// Given a func, replace all `GetCurrentStage` insts with the given stage, and rewrite all calls to
// stage specific functions to the specialized function for the given stage.
//
void specializeFuncToStage(
Stage stage,
IRGlobalValueWithCode* func,
Dictionary<IRInst*, Dictionary<Stage, IRInst*>>& mapFuncToStageSpecializedFunc)
{
// Collect all insts that may need to be modified.
List<IRInst*> instsToModify;
for (auto block : func->getBlocks())
{
for (auto inst : block->getChildren())
{
switch (inst->getOp())
{
case kIROp_GetCurrentStage:
case kIROp_Call:
instsToModify.add(inst);
break;
}
}
}
IRInst* stageVal = nullptr;
IRBuilder builder(func);
for (auto inst : instsToModify)
{
builder.setInsertBefore(inst);
switch (inst->getOp())
{
case kIROp_GetCurrentStage:
{
// Replace `GetCurrentStage` with the stage it is specialized to.
if (!stageVal)
{
stageVal = builder.getIntValue((IRIntegerValue)stage);
}
inst->replaceUsesWith(stageVal);
inst->removeAndDeallocate();
break;
}
case kIROp_Call:
{
// Replace calls to stage specific functions with the specialized function for the
// given stage.
auto callInst = static_cast<IRCall*>(inst);
auto callee = callInst->getCallee();
auto specializedFuncs = mapFuncToStageSpecializedFunc.tryGetValue(callee);
if (specializedFuncs)
{
auto specializedFunc = specializedFuncs->tryGetValue(stage);
if (specializedFunc)
{
builder.replaceOperand(callInst->getCalleeUse(), *specializedFunc);
}
}
break;
}
}
}
}
void specializeStageSwitch(IRModule* module)
{
Dictionary<IRInst*, HashSet<IRFunc*>> mapInstToReferencingEntryPoints;
buildEntryPointReferenceGraph(mapInstToReferencingEntryPoints, module);
HashSet<IRInst*> stageSpecificFunctions;
discoverStageSpecificFunctions(stageSpecificFunctions, module);
// Clone all stage specific functions for each stage they are used in.
Dictionary<IRInst*, Dictionary<Stage, IRInst*>> mapFuncToStageSpecializedFunc;
for (auto func : stageSpecificFunctions)
{
auto referencingEntryPoints = mapInstToReferencingEntryPoints.tryGetValue(func);
if (!referencingEntryPoints)
continue;
if (func->findDecoration<IREntryPointDecoration>())
continue;
Dictionary<Stage, IRInst*> specializedFuncs;
for (auto entryPoint : *referencingEntryPoints)
{
auto entryPointDecor = entryPoint->findDecoration<IREntryPointDecoration>();
if (!entryPointDecor)
continue;
auto stage = entryPointDecor->getProfile().getStage();
auto stageSpecializedFunc = specializedFuncs.tryGetValue(stage);
if (stageSpecializedFunc)
continue;
IRCloneEnv cloneEnv;
IRBuilder builder(func);
builder.setInsertBefore(func);
auto clonedFunc = cloneInst(&cloneEnv, &builder, func);
specializedFuncs[stage] = clonedFunc;
}
mapFuncToStageSpecializedFunc.add(func, _Move(specializedFuncs));
}
// Rewrite entrypoint and cloned functions to replace `GetCurrentStage` with the stage they are
// specialized to.
for (auto func : stageSpecificFunctions)
{
// Is this an entrypoint?
if (auto entryPointDecor = func->findDecoration<IREntryPointDecoration>())
{
auto stage = entryPointDecor->getProfile().getStage();
specializeFuncToStage(
stage,
as<IRGlobalValueWithCode>(func),
mapFuncToStageSpecializedFunc);
}
else
{
// Is this a cloned function?
auto specializedFuncs = mapFuncToStageSpecializedFunc.tryGetValue(func);
if (!specializedFuncs)
continue;
for (auto pair : *specializedFuncs)
{
auto stage = pair.first;
auto specializedFunc = pair.second;
specializeFuncToStage(
stage,
as<IRGlobalValueWithCode>(specializedFunc),
mapFuncToStageSpecializedFunc);
}
}
}
// Remove all original stage specific functions.
for (auto f : mapFuncToStageSpecializedFunc)
{
f.first->removeAndDeallocate();
}
}
} // namespace Slang
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