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Port refprune pass to NewPassManager #1057

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Sep 24, 2024
Merged

Port refprune pass to NewPassManager #1057

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6b21b2a
Port refprune to NewPassManager
yashssh May 21, 2024
2d9f8e6
clang format
yashssh Jul 10, 2024
4554776
Revert "clang format"
yashssh Jul 18, 2024
1e85a8b
Port refprune pass tests to npm
yashssh Jul 19, 2024
2203726
clang-format 14 based formatting
yashssh Jul 19, 2024
a619eb8
Doc for add_refprune_pass()
yashssh Aug 19, 2024
5e5b5c6
Add back tests for legacy version of refprune_pass
yashssh Aug 19, 2024
13cb543
Merge branch 'main' into npm-refprune
yashssh Aug 19, 2024
0251e46
Merge branch 'main' into npm-refprune
yashssh Sep 19, 2024
0b99743
Fix corrupted test after merge
yashssh Sep 19, 2024
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10 changes: 10 additions & 0 deletions docs/source/user-guide/binding/optimization-passes.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -169,6 +169,11 @@ The ``add_*`` methods supported by both pass manager classes are:
Add the `Simplify CFG
<https://llvm.org/docs/Passes.html#simplifycfg-simplify-the-cfg>`_ pass.

.. method:: add_refprune_pass()

Add the `Reference pruning
<https://github.com/numba/llvmlite/blob/main/ffi/custom_passes.cpp>`_ pass.

.. currentmodule:: llvmlite.binding

Legacy Pass Manager APIs
Expand Down Expand Up @@ -301,6 +306,11 @@ create and configure a :class:`PassManagerBuilder`.

See `instnamer pass documentation <http://llvm.org/docs/Passes.html#instnamer-assign-names-to-anonymous-instructions>`_.

* .. function:: add_refprune_pass()

Add the `Reference pruning
<https://github.com/numba/llvmlite/blob/main/ffi/custom_passes.cpp>`_ pass.

.. class:: ModulePassManager()
:no-index:

Expand Down
220 changes: 157 additions & 63 deletions ffi/custom_passes.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -26,10 +26,22 @@
using namespace llvm;

namespace llvm {
void initializeRefNormalizePassPass(PassRegistry &Registry);
void initializeRefPrunePassPass(PassRegistry &Registry);
void initializeRefNormalizeLegacyPassPass(PassRegistry &Registry);
void initializeRefPruneLegacyPassPass(PassRegistry &Registry);
Comment on lines +29 to +30
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Prefix the pass name with "Legacy" to be used with legacy pass manager

} // namespace llvm

namespace llvm {
struct OpaqueModulePassManager;
typedef OpaqueModulePassManager *LLVMModulePassManagerRef;
DEFINE_SIMPLE_CONVERSION_FUNCTIONS(ModulePassManager, LLVMModulePassManagerRef)

struct OpaqueFunctionPassManager;
typedef OpaqueFunctionPassManager *LLVMFunctionPassManagerRef;
DEFINE_SIMPLE_CONVERSION_FUNCTIONS(FunctionPassManager,
LLVMFunctionPassManagerRef)
} // namespace llvm

namespace {
/**
* Checks if a call instruction is an incref
*
Expand Down Expand Up @@ -104,13 +116,9 @@ template <class Tstack> struct raiiStack {
* A FunctionPass to reorder incref/decref instructions such that decrefs occur
* logically after increfs. This is a pre-requisite pass to the pruner passes.
*/
struct RefNormalizePass : public FunctionPass {
static char ID;
RefNormalizePass() : FunctionPass(ID) {
initializeRefNormalizePassPass(*PassRegistry::getPassRegistry());
}
struct RefNormalize {

bool runOnFunction(Function &F) override {
bool runOnFunction(Function &F) {
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This is the core of the RefNormalize pass, we will call this function from legacy and new version of RefNormalize pass.

bool mutated = false;
// For each basic block in F
for (BasicBlock &bb : F) {
Expand Down Expand Up @@ -158,7 +166,16 @@ struct RefNormalizePass : public FunctionPass {
}
};

struct RefPrunePass : public FunctionPass {
typedef enum {
None = 0b0000,
PerBasicBlock = 0b0001,
Diamond = 0b0010,
Fanout = 0b0100,
FanoutRaise = 0b1000,
All = PerBasicBlock | Diamond | Fanout | FanoutRaise
} Subpasses;

struct RefPrune {
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We have moved all the computation related functions from inside struct RefPrunePass : public FunctionPass to struct RefPrune so that we can re-use these functions from both the Legacy pass and the new pass.

static char ID;
static size_t stats_per_bb;
static size_t stats_diamond;
Expand All @@ -175,25 +192,21 @@ struct RefPrunePass : public FunctionPass {
/**
* Enum for setting which subpasses to run, there is no interdependence.
*/
enum Subpasses {
None = 0b0000,
PerBasicBlock = 0b0001,
Diamond = 0b0010,
Fanout = 0b0100,
FanoutRaise = 0b1000,
All = PerBasicBlock | Diamond | Fanout | FanoutRaise
} flags;

RefPrunePass(Subpasses flags = Subpasses::All, size_t subgraph_limit = -1)
: FunctionPass(ID), flags(flags), subgraph_limit(subgraph_limit) {
initializeRefPrunePassPass(*PassRegistry::getPassRegistry());
}
Subpasses flags;

DominatorTree &DT;
PostDominatorTree &PDT;

RefPrune(DominatorTree &DT, PostDominatorTree &PDT,
Subpasses flags = Subpasses::All, size_t subgraph_limit = -1)
: DT(DT), PDT(PDT), flags(flags), subgraph_limit(subgraph_limit) {}

bool isSubpassEnabledFor(Subpasses expected) {
return (flags & expected) == expected;
}

bool runOnFunction(Function &F) override {
bool runOnFunction(Function &F) {
// state for LLVM function pass mutated IR
bool mutated = false;

Expand Down Expand Up @@ -361,11 +374,6 @@ struct RefPrunePass : public FunctionPass {
*/
bool runDiamondPrune(Function &F) {
bool mutated = false;
// gets the dominator tree
auto &domtree = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
// gets the post-dominator tree
auto &postdomtree =
getAnalysis<PostDominatorTreeWrapperPass>().getPostDomTree();

// Find all increfs and decrefs in the Function and store them in
// incref_list and decref_list respectively.
Expand Down Expand Up @@ -394,8 +402,8 @@ struct RefPrunePass : public FunctionPass {
continue;

// incref DOM decref && decref POSTDOM incref
if (domtree.dominates(incref, decref) &&
postdomtree.dominates(decref, incref)) {
if (DT.dominates(incref, decref) &&
PDT.dominates(decref, incref)) {
// check that the decref cannot be executed multiple times
SmallBBSet tail_nodes;
tail_nodes.insert(decref->getParent());
Expand Down Expand Up @@ -1028,14 +1036,6 @@ struct RefPrunePass : public FunctionPass {
return NULL;
}

/**
* getAnalysisUsage() LLVM plumbing for the pass
*/
void getAnalysisUsage(AnalysisUsage &Info) const override {
Info.addRequired<DominatorTreeWrapperPass>();
Info.addRequired<PostDominatorTreeWrapperPass>();
}

/**
* Checks if the first argument to the supplied call_inst is NULL and
* returns true if so, false otherwise.
Expand Down Expand Up @@ -1163,34 +1163,128 @@ struct RefPrunePass : public FunctionPass {
}
}
}
}; // end of struct RefPrunePass
}; // end of struct RefPrune

} // namespace

class RefPrunePass : public PassInfoMixin<RefPrunePass> {

public:
Subpasses flags;
size_t subgraph_limit;
RefPrunePass(Subpasses flags = Subpasses::All, size_t subgraph_limit = -1)
: flags(flags), subgraph_limit(subgraph_limit) {}

PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM) {
auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
auto &PDT = AM.getResult<PostDominatorTreeAnalysis>(F);
if (RefPrune(DT, PDT, flags, subgraph_limit).runOnFunction(F)) {
return PreservedAnalyses::none();
}

return PreservedAnalyses::all();
}
};
Comment on lines +1170 to +1187
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Now that we have renamed the pass with "Legacy" keyword, we are free to create another pass with the name RefPrunePass, we will call this pass from NewPassManager . The passes for new pass manager follow this template mixin inheritance syntax that's visible here. There's also a difference in how we get the Analysis results needed for the pass to run, instead of explicitly specifying dependencies in getAnalysisUsage function we can directly query the NPM analysis manager for the result.

Note that wrapped in all this new pass manager syntax we are calling runOnFunction(F) which actually does the computation for this pass and is also used by legacy version of this pass.


char RefNormalizePass::ID = 0;
char RefPrunePass::ID = 0;
class RefNormalizePass : public PassInfoMixin<RefNormalizePass> {

size_t RefPrunePass::stats_per_bb = 0;
size_t RefPrunePass::stats_diamond = 0;
size_t RefPrunePass::stats_fanout = 0;
size_t RefPrunePass::stats_fanout_raise = 0;
public:
RefNormalizePass() = default;

INITIALIZE_PASS(RefNormalizePass, "nrtrefnormalizepass", "Normalize NRT refops",
false, false)
PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM) {
RefNormalize().runOnFunction(F);

INITIALIZE_PASS_BEGIN(RefPrunePass, "nrtrefprunepass", "Prune NRT refops",
false, false)
return PreservedAnalyses::all();
}
};

class RefNormalizeLegacyPass : public FunctionPass {
public:
static char ID;
RefNormalizeLegacyPass() : FunctionPass(ID) {
initializeRefNormalizeLegacyPassPass(*PassRegistry::getPassRegistry());
}

bool runOnFunction(Function &F) override {
return RefNormalize().runOnFunction(F);
};
};

class RefPruneLegacyPass : public FunctionPass {

public:
static char ID; // Pass identification, replacement for typeid
// The maximum number of nodes that the fanout pruners will look at.
size_t subgraph_limit;
Subpasses flags;
RefPruneLegacyPass(Subpasses flags = Subpasses::All,
size_t subgraph_limit = -1)
: FunctionPass(ID), flags(flags), subgraph_limit(subgraph_limit) {
initializeRefPruneLegacyPassPass(*PassRegistry::getPassRegistry());
}

bool runOnFunction(Function &F) override {
auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();

auto &PDT =
getAnalysis<PostDominatorTreeWrapperPass>().getPostDomTree();

return RefPrune(DT, PDT, flags, subgraph_limit).runOnFunction(F);
};

/**
* getAnalysisUsage() LLVM plumbing for the pass
*/
void getAnalysisUsage(AnalysisUsage &Info) const override {
Info.addRequired<DominatorTreeWrapperPass>();
Info.addRequired<PostDominatorTreeWrapperPass>();
}
};

char RefNormalizeLegacyPass::ID = 0;
char RefPruneLegacyPass::ID = 0;

size_t RefPrune::stats_per_bb = 0;
size_t RefPrune::stats_diamond = 0;
size_t RefPrune::stats_fanout = 0;
size_t RefPrune::stats_fanout_raise = 0;

INITIALIZE_PASS(RefNormalizeLegacyPass, "nrtRefNormalize",
"Normalize NRT refops", false, false)

INITIALIZE_PASS_BEGIN(RefPruneLegacyPass, "nrtRefPruneLegacyPass",
"Prune NRT refops", false, false)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass)

INITIALIZE_PASS_END(RefPrunePass, "refprunepass", "Prune NRT refops", false,
false)
INITIALIZE_PASS_END(RefPruneLegacyPass, "RefPruneLegacyPass",
"Prune NRT refops", false, false)

extern "C" {

API_EXPORT(void)
LLVMPY_AddRefPrunePass(LLVMPassManagerRef PM, int subpasses,
size_t subgraph_limit) {
unwrap(PM)->add(new RefNormalizePass());
LLVMPY_AddLegacyRefPrunePass(LLVMPassManagerRef PM, int subpasses,
size_t subgraph_limit) {
unwrap(PM)->add(new RefNormalizeLegacyPass());
unwrap(PM)->add(
new RefPrunePass((RefPrunePass::Subpasses)subpasses, subgraph_limit));
new RefPruneLegacyPass((Subpasses)subpasses, subgraph_limit));
}

API_EXPORT(void)
LLVMPY_AddRefPrunePass_module(LLVMModulePassManagerRef MPM, int subpasses,
size_t subgraph_limit) {
llvm::unwrap(MPM)->addPass(
createModuleToFunctionPassAdaptor(RefNormalizePass()));
llvm::unwrap(MPM)->addPass(createModuleToFunctionPassAdaptor(
RefPrunePass((Subpasses)subpasses, subgraph_limit)));
}

API_EXPORT(void)
LLVMPY_AddRefPrunePass_function(LLVMFunctionPassManagerRef FPM, int subpasses,
size_t subgraph_limit) {
llvm::unwrap(FPM)->addPass(RefNormalizePass());
llvm::unwrap(FPM)->addPass(
RefPrunePass((Subpasses)subpasses, subgraph_limit));
Comment on lines +1273 to +1287
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API to register new passes in MPM and FPM respectively.

}

/**
Expand All @@ -1207,24 +1301,24 @@ typedef struct PruneStats {
API_EXPORT(void)
LLVMPY_DumpRefPruneStats(PRUNESTATS *buf, bool do_print) {
/* PRUNESTATS is updated with the statistics about what has been pruned from
* the RefPrunePass static state vars. This isn't threadsafe but neither is
* the RefPrune static state vars. This isn't threadsafe but neither is
* the LLVM pass infrastructure so it's all done under a python thread lock.
*
* do_print if set will print the stats to stderr.
*/
if (do_print) {
errs() << "refprune stats "
<< "per-BB " << RefPrunePass::stats_per_bb << " "
<< "diamond " << RefPrunePass::stats_diamond << " "
<< "fanout " << RefPrunePass::stats_fanout << " "
<< "fanout+raise " << RefPrunePass::stats_fanout_raise << " "
<< "per-BB " << RefPrune::stats_per_bb << " "
<< "diamond " << RefPrune::stats_diamond << " "
<< "fanout " << RefPrune::stats_fanout << " "
<< "fanout+raise " << RefPrune::stats_fanout_raise << " "
<< "\n";
};

buf->basicblock = RefPrunePass::stats_per_bb;
buf->diamond = RefPrunePass::stats_diamond;
buf->fanout = RefPrunePass::stats_fanout;
buf->fanout_raise = RefPrunePass::stats_fanout_raise;
buf->basicblock = RefPrune::stats_per_bb;
buf->diamond = RefPrune::stats_diamond;
buf->fanout = RefPrune::stats_fanout;
buf->fanout_raise = RefPrune::stats_fanout_raise;
}

} // extern "C"
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