SamplePGO - Reduce memory utilization by 10x.

DenseMap is the wrong data structure to use for sample records and call
sites.  The keys are too large, causing massive core memory growth when
reading profiles.

Before this patch, a 21Mb input profile was causing the compiler to grow
to 3Gb in memory.  By switching to std::map, the compiler now grows to
300Mb in memory.

There still are some opportunities for memory footprint reduction. I'll
be looking at those next.

llvm-svn: 255389

llvm/include/llvm/ProfileData/SampleProf.h

@@ -15,12 +15,13 @@
 #ifndef LLVM_PROFILEDATA_SAMPLEPROF_H_
 #define LLVM_PROFILEDATA_SAMPLEPROF_H_
 
-#include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/raw_ostream.h"
+
+#include <map>
 #include <system_error>
 
 namespace llvm {
@@ -105,57 +106,6 @@ struct CallsiteLocation : public LineLocation {
 
 raw_ostream &operator<<(raw_ostream &OS, const CallsiteLocation &Loc);
 
-} // End namespace sampleprof
-
-template <> struct DenseMapInfo<sampleprof::LineLocation> {
-  typedef DenseMapInfo<uint32_t> OffsetInfo;
-  typedef DenseMapInfo<uint32_t> DiscriminatorInfo;
-  static inline sampleprof::LineLocation getEmptyKey() {
-    return sampleprof::LineLocation(OffsetInfo::getEmptyKey(),
-                                    DiscriminatorInfo::getEmptyKey());
-  }
-  static inline sampleprof::LineLocation getTombstoneKey() {
-    return sampleprof::LineLocation(OffsetInfo::getTombstoneKey(),
-                                    DiscriminatorInfo::getTombstoneKey());
-  }
-  static inline unsigned getHashValue(sampleprof::LineLocation Val) {
-    return DenseMapInfo<std::pair<uint32_t, uint32_t>>::getHashValue(
-        std::pair<uint32_t, uint32_t>(Val.LineOffset, Val.Discriminator));
-  }
-  static inline bool isEqual(sampleprof::LineLocation LHS,
-                             sampleprof::LineLocation RHS) {
-    return LHS.LineOffset == RHS.LineOffset &&
-           LHS.Discriminator == RHS.Discriminator;
-  }
-};
-
-template <> struct DenseMapInfo<sampleprof::CallsiteLocation> {
-  typedef DenseMapInfo<uint32_t> OffsetInfo;
-  typedef DenseMapInfo<uint32_t> DiscriminatorInfo;
-  typedef DenseMapInfo<StringRef> CalleeNameInfo;
-  static inline sampleprof::CallsiteLocation getEmptyKey() {
-    return sampleprof::CallsiteLocation(OffsetInfo::getEmptyKey(),
-                                        DiscriminatorInfo::getEmptyKey(), "");
-  }
-  static inline sampleprof::CallsiteLocation getTombstoneKey() {
-    return sampleprof::CallsiteLocation(OffsetInfo::getTombstoneKey(),
-                                        DiscriminatorInfo::getTombstoneKey(),
-                                        "");
-  }
-  static inline unsigned getHashValue(sampleprof::CallsiteLocation Val) {
-    return DenseMapInfo<std::pair<uint32_t, uint32_t>>::getHashValue(
-        std::pair<uint32_t, uint32_t>(Val.LineOffset, Val.Discriminator));
-  }
-  static inline bool isEqual(sampleprof::CallsiteLocation LHS,
-                             sampleprof::CallsiteLocation RHS) {
-    return LHS.LineOffset == RHS.LineOffset &&
-           LHS.Discriminator == RHS.Discriminator &&
-           LHS.CalleeName.equals(RHS.CalleeName);
-  }
-};
-
-namespace sampleprof {
-
 /// Representation of a single sample record.
 ///
 /// A sample record is represented by a positive integer value, which
@@ -176,9 +126,7 @@ class SampleRecord {
   ///
   /// Sample counts accumulate using saturating arithmetic, to avoid wrapping
   /// around unsigned integers.
-  void addSamples(uint64_t S) {
-    NumSamples = SaturatingAdd(NumSamples, S);
-  }
+  void addSamples(uint64_t S) { NumSamples = SaturatingAdd(NumSamples, S); }
 
   /// Add called function \p F with samples \p S.
   ///
@@ -212,9 +160,9 @@ class SampleRecord {
 
 raw_ostream &operator<<(raw_ostream &OS, const SampleRecord &Sample);
 
-typedef DenseMap<LineLocation, SampleRecord> BodySampleMap;
+typedef std::map<LineLocation, SampleRecord> BodySampleMap;
 class FunctionSamples;
-typedef DenseMap<CallsiteLocation, FunctionSamples> CallsiteSampleMap;
+typedef std::map<CallsiteLocation, FunctionSamples> CallsiteSampleMap;
 
 /// Representation of the samples collected for a function.
 ///
@@ -345,10 +293,10 @@ raw_ostream &operator<<(raw_ostream &OS, const FunctionSamples &FS);
 /// order of LocationT.
 template <class LocationT, class SampleT> class SampleSorter {
 public:
-  typedef detail::DenseMapPair<LocationT, SampleT> SamplesWithLoc;
+  typedef std::pair<const LocationT, SampleT> SamplesWithLoc;
   typedef SmallVector<const SamplesWithLoc *, 20> SamplesWithLocList;
 
-  SampleSorter(const DenseMap<LocationT, SampleT> &Samples) {
+  SampleSorter(const std::map<LocationT, SampleT> &Samples) {
     for (const auto &I : Samples)
       V.push_back(&I);
     std::stable_sort(V.begin(), V.end(),

llvm/include/llvm/ProfileData/SampleProfReader.h

@@ -184,7 +184,6 @@
 #ifndef LLVM_PROFILEDATA_SAMPLEPROFREADER_H
 #define LLVM_PROFILEDATA_SAMPLEPROFREADER_H
 
-#include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"

llvm/lib/Transforms/IPO/SampleProfile.cpp

@@ -223,7 +223,7 @@ class SampleCoverageTracker {
   }
 
 private:
-  typedef DenseMap<LineLocation, unsigned> BodySampleCoverageMap;
+  typedef std::map<LineLocation, unsigned> BodySampleCoverageMap;
   typedef DenseMap<const FunctionSamples *, BodySampleCoverageMap>
       FunctionSamplesCoverageMap;