[llvm] 18839be - [ADT] Remove StatisticBase and make NoopStatistic empty
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Mon Apr 26 16:47:42 PDT 2021
Author: Fangrui Song
Date: 2021-04-26T16:47:32-07:00
New Revision: 18839be9c5c8b9f882dd241769784035b082d4e1
URL: https://github.com/llvm/llvm-project/commit/18839be9c5c8b9f882dd241769784035b082d4e1
DIFF: https://github.com/llvm/llvm-project/commit/18839be9c5c8b9f882dd241769784035b082d4e1.diff
LOG: [ADT] Remove StatisticBase and make NoopStatistic empty
In LLVM_ENABLE_STATS=0 builds, `llvm::Statistic` maps to `llvm::NoopStatistic`
but has 3 mostly unused pointers. GlobalOpt considers that the pointers can
potentially retain allocated objects, so GlobalOpt cannot optimize out the
`NoopStatistic` variables (see D69428 for more context), wasting 23KiB for stage
2 clang.
This patch makes `NoopStatistic` empty and thus reclaims the wasted space. The
clang size is even smaller than applying D69428 (slightly smaller in both .bss and
.text).
```
# This means the D69428 optimization on clang is mostly nullified by this patch.
HEAD+D69428: size(.bss) = 0x0725a8
HEAD+D101211: size(.bss) = 0x072238
# bloaty - HEAD+D69428 vs HEAD+D101211
# With D101211, we also save a lot of string table space (.rodata).
FILE SIZE VM SIZE
-------------- --------------
-0.0% -32 -0.0% -24 .eh_frame
-0.0% -336 [ = ] 0 .symtab
-0.0% -360 [ = ] 0 .strtab
[ = ] 0 -0.2% -880 .bss
-0.0% -2.11Ki -0.0% -2.11Ki .rodata
-0.0% -2.89Ki -0.0% -2.89Ki .text
-0.0% -5.71Ki -0.0% -5.88Ki TOTAL
```
Note: LoopFuse is a disabled pass. For now this patch adds
`#if LLVM_ENABLE_STATS` so `OptimizationRemarkMissed` is skipped in
LLVM_ENABLE_STATS==0 builds. If these `OptimizationRemarkMissed` are useful in
LLVM_ENABLE_STATS==0 builds, we can replace `llvm::Statistic` with
`llvm::TrackingStatistic`, or use a different abstraction to keep track of the strings.
Similarly, skip the code in `mlir/lib/Pass/PassStatistics.cpp` which
calls `getName`/`getDesc`/`getValue`.
Reviewed By: lattner
Differential Revision: https://reviews.llvm.org/D101211
Added:
Modified:
llvm/include/llvm/ADT/Statistic.h
llvm/lib/Transforms/Scalar/LoopFuse.cpp
mlir/include/mlir/Pass/Pass.h
mlir/lib/Pass/PassStatistics.cpp
mlir/test/Pass/pipeline-stats.mlir
Removed:
################################################################################
diff --git a/llvm/include/llvm/ADT/Statistic.h b/llvm/include/llvm/ADT/Statistic.h
index aa338ccff19a6..de7dabc382c37 100644
--- a/llvm/include/llvm/ADT/Statistic.h
+++ b/llvm/include/llvm/ADT/Statistic.h
@@ -46,27 +46,22 @@ class raw_ostream;
class raw_fd_ostream;
class StringRef;
-class StatisticBase {
+class TrackingStatistic {
public:
- const char *DebugType;
- const char *Name;
- const char *Desc;
+ const char *const DebugType;
+ const char *const Name;
+ const char *const Desc;
- StatisticBase(const char *DebugType, const char *Name, const char *Desc)
- : DebugType(DebugType), Name(Name), Desc(Desc) {}
-
- const char *getDebugType() const { return DebugType; }
- const char *getName() const { return Name; }
- const char *getDesc() const { return Desc; }
-};
-
-class TrackingStatistic : public StatisticBase {
-public:
std::atomic<unsigned> Value;
std::atomic<bool> Initialized;
TrackingStatistic(const char *DebugType, const char *Name, const char *Desc)
- : StatisticBase(DebugType, Name, Desc), Value(0), Initialized(false) {}
+ : DebugType(DebugType), Name(Name), Desc(Desc), Value(0),
+ Initialized(false) {}
+
+ const char *getDebugType() const { return DebugType; }
+ const char *getName() const { return Name; }
+ const char *getDesc() const { return Desc; }
unsigned getValue() const { return Value.load(std::memory_order_relaxed); }
@@ -132,9 +127,10 @@ class TrackingStatistic : public StatisticBase {
void RegisterStatistic();
};
-class NoopStatistic : public StatisticBase {
+class NoopStatistic {
public:
- using StatisticBase::StatisticBase;
+ NoopStatistic(const char * /*DebugType*/, const char * /*Name*/,
+ const char * /*Desc*/) {}
unsigned getValue() const { return 0; }
diff --git a/llvm/lib/Transforms/Scalar/LoopFuse.cpp b/llvm/lib/Transforms/Scalar/LoopFuse.cpp
index 63f02d0269160..ca19913e37ee1 100644
--- a/llvm/lib/Transforms/Scalar/LoopFuse.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopFuse.cpp
@@ -372,11 +372,13 @@ struct FusionCandidate {
bool reportInvalidCandidate(llvm::Statistic &Stat) const {
using namespace ore;
assert(L && Preheader && "Fusion candidate not initialized properly!");
+#if LLVM_ENABLE_STATS
++Stat;
ORE.emit(OptimizationRemarkAnalysis(DEBUG_TYPE, Stat.getName(),
L->getStartLoc(), Preheader)
<< "[" << Preheader->getParent()->getName() << "]: "
<< "Loop is not a candidate for fusion: " << Stat.getDesc());
+#endif
return false;
}
};
@@ -1533,6 +1535,7 @@ struct LoopFuser {
assert(FC0.Preheader && FC1.Preheader &&
"Expecting valid fusion candidates");
using namespace ore;
+#if LLVM_ENABLE_STATS
++Stat;
ORE.emit(RemarkKind(DEBUG_TYPE, Stat.getName(), FC0.L->getStartLoc(),
FC0.Preheader)
@@ -1540,6 +1543,7 @@ struct LoopFuser {
<< "]: " << NV("Cand1", StringRef(FC0.Preheader->getName()))
<< " and " << NV("Cand2", StringRef(FC1.Preheader->getName()))
<< ": " << Stat.getDesc());
+#endif
}
/// Fuse two guarded fusion candidates, creating a new fused loop.
diff --git a/mlir/include/mlir/Pass/Pass.h b/mlir/include/mlir/Pass/Pass.h
index 10b1a5c57a816..736ad422d346c 100644
--- a/mlir/include/mlir/Pass/Pass.h
+++ b/mlir/include/mlir/Pass/Pass.h
@@ -139,10 +139,6 @@ class Pass {
/// Assign the statistic to the given value.
Statistic &operator=(unsigned value);
-
- private:
- /// Hide some of the details of llvm::Statistic that we don't use.
- using llvm::Statistic::getDebugType;
};
/// Returns the main statistics for this pass instance.
diff --git a/mlir/lib/Pass/PassStatistics.cpp b/mlir/lib/Pass/PassStatistics.cpp
index d909c98abf563..425aeae35e059 100644
--- a/mlir/lib/Pass/PassStatistics.cpp
+++ b/mlir/lib/Pass/PassStatistics.cpp
@@ -64,6 +64,7 @@ static void printResultsAsList(raw_ostream &os, OpPassManager &pm) {
// If this is not an adaptor, add the stats to the list if there are any.
if (!adaptor) {
+#if LLVM_ENABLE_STATS
auto statistics = pass->getStatistics();
if (statistics.empty())
return;
@@ -76,6 +77,7 @@ static void printResultsAsList(raw_ostream &os, OpPassManager &pm) {
for (auto &it : llvm::enumerate(pass->getStatistics()))
passEntry[it.index()].value += it.value()->getValue();
}
+#endif
return;
}
@@ -103,6 +105,7 @@ static void printResultsAsList(raw_ostream &os, OpPassManager &pm) {
/// Print the results in pipeline mode that mirrors the internal pass manager
/// structure.
static void printResultsAsPipeline(raw_ostream &os, OpPassManager &pm) {
+#if LLVM_ENABLE_STATS
std::function<void(unsigned, Pass *)> printPass = [&](unsigned indent,
Pass *pass) {
if (auto *adaptor = dyn_cast<OpToOpPassAdaptor>(pass)) {
@@ -132,6 +135,7 @@ static void printResultsAsPipeline(raw_ostream &os, OpPassManager &pm) {
};
for (Pass &pass : pm.getPasses())
printPass(/*indent=*/0, &pass);
+#endif
}
static void printStatistics(OpPassManager &pm, PassDisplayMode displayMode) {
diff --git a/mlir/test/Pass/pipeline-stats.mlir b/mlir/test/Pass/pipeline-stats.mlir
index 6aee2bfc83145..e75dfe41befca 100644
--- a/mlir/test/Pass/pipeline-stats.mlir
+++ b/mlir/test/Pass/pipeline-stats.mlir
@@ -1,3 +1,4 @@
+// REQUIRES: asserts
// RUN: mlir-opt %s -verify-each=true -pass-pipeline='func(test-stats-pass,test-stats-pass)' -pass-statistics -pass-statistics-display=list 2>&1 | FileCheck -check-prefix=LIST %s
// RUN: mlir-opt %s -verify-each=true -pass-pipeline='func(test-stats-pass,test-stats-pass)' -pass-statistics -pass-statistics-display=pipeline 2>&1 | FileCheck -check-prefix=PIPELINE %s
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