[llvm] [Bolt] Add a new hidden option to perf2bolt for testing purpose (PR #163785)

[Amir Ayupov via llvm-commits]

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@@ -372,6 +379,80 @@ void DataAggregator::parsePreAggregated() {
   }
 }
 
+bool DataAggregator::isMMapEvent(StringRef Line) {
+  // Short cut to avoid string find is possible.
+  if (Line.empty() || Line.size() < 50)
+    return false;
+
+  // Check that PERF_RECORD_MMAP2 or PERF_RECORD_MMAP appear in the line.
+  return Line.contains("PERF_RECORD_MMAP");
+}
+
+void DataAggregator::parsePerfScriptEvents() {
+  outs() << "PERF2BOLT: parsing a hybrid perf-script events...\n";
+  NamedRegionTimer T("parsePerfScriptEvents", "Parsing perf-script events",
+                     TimerGroupName, TimerGroupDesc, opts::TimeAggregator);
+
+  ErrorOr<std::unique_ptr<MemoryBuffer>> MB =
+      MemoryBuffer::getFileOrSTDIN(Filename);
+  if (std::error_code EC = MB.getError()) {
+    errs() << "PERF2BOLT-ERROR: cannot open " << Filename << ": "
+           << EC.message() << "\n";
+    exit(1);
+  }
+
+  FileBuf = std::move(*MB);
+  ParsingBuf = FileBuf->getBuffer();
+  Col = 0;
+  Line = 1;
+  std::string MMapEvents = "";
+  std::string BranchEvents = "";
----------------
aaupov wrote:

Constructing these strings might be really expensive for large perf script inputs. Did you check if running `parseMMapEvents` and `parseBranchEvents` directly on the parsing buffer works? `parseMMapEvents` is supposed to parse as much lines as it (advancing Line/Col), returning with an error code when parsing error occurs. We can consume the error and invoke parseBranchEvents on the buffer.

https://github.com/llvm/llvm-project/pull/163785