[Memprof] Adds the option to collect AccessCountHistograms for memprof. (#94264)

Adds compile time flag -mllvm -memprof-histogram and runtime flag
histogram=true|false to turn Histogram collection on and off. The
-memprof-histogram flag relies on -memprof-use-callbacks=true to work.

Updates shadow mapping logic in histogram mode from having one 8 byte
counter for 64 bytes, to 1 byte for 8 bytes, capped at 255. Only
supports this granularity as of now.

Updates the RawMemprofReader and serializing MemoryInfoBlocks to binary
format, including changing to a new version of the raw binary format
from version 3 to version 4.

Updates creating MemoryInfoBlocks with and without Histograms. When two
MemoryInfoBlocks are merged, AccessCounts are summed up and the shorter
Histogram is removed.

Adds a memprof_histogram test case.

Initial commit for adding AccessCountHistograms up until RawProfile for
memprof

1 files changed, 3 insertions, 3 deletions

diff --git a/llvm/unittests/ProfileData/MemProfTest.cpp b/llvm/unittests/ProfileData/MemProfTest.cpp
index 15eb59e..14623e18 100644
--- a/llvm/unittests/ProfileData/MemProfTest.cpp
+++ b/llvm/unittests/ProfileData/MemProfTest.cpp
@@ -247,7 +247,7 @@ TEST(MemProf, FillsValue) {
 TEST(MemProf, PortableWrapper) {
   MemInfoBlock Info(/*size=*/16, /*access_count=*/7, /*alloc_timestamp=*/1000,
                     /*dealloc_timestamp=*/2000, /*alloc_cpu=*/3,
-                    /*dealloc_cpu=*/4);
+                    /*dealloc_cpu=*/4, /*Histogram=*/0, /*HistogramSize=*/0);
 
   const auto Schema = llvm::memprof::getFullSchema();
   PortableMemInfoBlock WriteBlock(Info, Schema);
@@ -276,7 +276,7 @@ TEST(MemProf, RecordSerializationRoundTripVersion0And1) {
 
   MemInfoBlock Info(/*size=*/16, /*access_count=*/7, /*alloc_timestamp=*/1000,
                     /*dealloc_timestamp=*/2000, /*alloc_cpu=*/3,
-                    /*dealloc_cpu=*/4);
+                    /*dealloc_cpu=*/4, /*Histogram=*/0, /*HistogramSize=*/0);
 
   llvm::SmallVector<llvm::SmallVector<FrameId>> AllocCallStacks = {
       {0x123, 0x345}, {0x123, 0x567}};
@@ -310,7 +310,7 @@ TEST(MemProf, RecordSerializationRoundTripVerion2) {
 
   MemInfoBlock Info(/*size=*/16, /*access_count=*/7, /*alloc_timestamp=*/1000,
                     /*dealloc_timestamp=*/2000, /*alloc_cpu=*/3,
-                    /*dealloc_cpu=*/4);
+                    /*dealloc_cpu=*/4, /*Histogram=*/0, /*HistogramSize=*/0);
 
   llvm::SmallVector<llvm::memprof::CallStackId> CallStackIds = {0x123, 0x456};