[BOLT][heatmap] Produce zoomed-out heatmaps (#140153)

Add a capability to produce multiple heatmaps with given bucket sizes.

The default heatmap block size (64B) could be too fine-grained for
large binaries. Extend the option `block-size` to accept a list of
bucket sizes for additional heatmaps with coarser granularity. The
heatmap is simply rescaled so provided sizes should be multiples of
each other. Human-readable suffixes can be used, e.g. 4K, 16kb, 1MiB.

New defaults: 64B (base bucket size), 4KB (default page size),
256KB (for large binaries).

Test Plan: updated heatmap-preagg.test

bolt/lib/Profile/DataAggregator.cpp

@@ -1314,8 +1314,9 @@ std::error_code DataAggregator::printLBRHeatMap() {
     opts::HeatmapMaxAddress = 0xffffffffffffffff;
     opts::HeatmapMinAddress = KernelBaseAddr;
   }
-  Heatmap HM(opts::HeatmapBlock, opts::HeatmapMinAddress,
-             opts::HeatmapMaxAddress, getTextSections(BC));
+  opts::HeatmapBlockSizes &HMBS = opts::HeatmapBlock;
+  Heatmap HM(HMBS[0], opts::HeatmapMinAddress, opts::HeatmapMaxAddress,
+             getTextSections(BC));
   auto getSymbolValue = [&](const MCSymbol *Symbol) -> uint64_t {
     if (Symbol)
       if (ErrorOr<uint64_t> SymValue = BC->getSymbolValue(*Symbol))
@@ -1365,6 +1366,14 @@ std::error_code DataAggregator::printLBRHeatMap() {
     HM.printCDF(opts::HeatmapOutput + ".csv");
     HM.printSectionHotness(opts::HeatmapOutput + "-section-hotness.csv");
   }
+  // Provide coarse-grained heatmaps if requested via zoom-out scales
+  for (const uint64_t NewBucketSize : ArrayRef(HMBS).drop_front()) {
+    HM.resizeBucket(NewBucketSize);
+    if (opts::HeatmapOutput == "-")
+      HM.print(opts::HeatmapOutput);
+    else
+      HM.print(formatv("{0}-{1}", opts::HeatmapOutput, NewBucketSize).str());
+  }
 
   return std::error_code();
 }