[BOLT][CSSPGO] Pseudo probe decoding

Summary:
Make bolt decode pseudo probe section in binary

For more detail of pseudo probe, check https://reviews.llvm.org/D86490.

(cherry picked from FBD28856316)

bolt/src/BinaryContext.h

@@ -31,6 +31,7 @@
 #include "llvm/MC/MCInstrInfo.h"
 #include "llvm/MC/MCObjectFileInfo.h"
 #include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCPseudoProbe.h"
 #include "llvm/MC/MCSectionELF.h"
 #include "llvm/MC/MCSectionMachO.h"
 #include "llvm/MC/MCSymbol.h"
@@ -591,6 +592,9 @@ public:
   /// special linux kernel sections
   std::unordered_map<uint64_t, std::vector<LKInstructionMarkerInfo>> LKMarkers;
 
+  /// PseudoProbe decoder
+  MCPseudoProbeDecoder ProbeDecoder;
+
   /// DWARF encoding. Available encoding types defined in BinaryFormat/Dwarf.h
   /// enum Constants, e.g. DW_EH_PE_omit.
   unsigned TTypeEncoding = dwarf::DW_EH_PE_omit;

bolt/src/RewriteInstance.cpp

@@ -272,6 +272,11 @@ PrintSDTMarkers("print-sdt",
   cl::Hidden,
   cl::cat(BoltCategory));
 
+static cl::opt<bool>
+    PrintPseudoProbe("print-pseudo-probe",
+                     cl::desc("print pseudo probe related info"),
+                     cl::ZeroOrMore, cl::Hidden, cl::cat(BoltCategory));
+
 static cl::opt<cl::boolOrDefault>
 RelocationMode("relocs",
   cl::desc("use relocations in the binary (default=autodetect)"),
@@ -684,6 +689,40 @@ void RewriteInstance::parseSDTNotes() {
     printSDTMarkers();
 }
 
+void RewriteInstance::parsePseudoProbe() {
+  if (!PseudoProbeDescSection && !PseudoProbeSection)
+    // pesudo probe is not added to binary. It is normal and no warning needed.
+    return;
+  // If only one section is found, it might mean the ELF is corrupted.
+  if (!PseudoProbeDescSection) {
+    errs() << "BOLT-WARNING: fail in reading .pseudo_probe_desc binary\n";
+    return;
+  } else if (!PseudoProbeSection) {
+    errs() << "BOLT-WARNING: fail in reading .pseudo_probe binary\n";
+    return;
+  }
+
+  StringRef Contents = PseudoProbeDescSection->getContents();
+  if (!BC->ProbeDecoder.buildGUID2FuncDescMap(
+          reinterpret_cast<const uint8_t *>(Contents.data()),
+          Contents.size())) {
+    errs() << "BOLT-WARNING: fail in building GUID2FuncDescMap\n";
+    return;
+  }
+  Contents = PseudoProbeSection->getContents();
+  if (!BC->ProbeDecoder.buildAddress2ProbeMap(
+          reinterpret_cast<const uint8_t *>(Contents.data()),
+          Contents.size())) {
+    errs() << "BOLT-WARNING: fail in building Address2ProbeMap\n";
+    return;
+  }
+
+  if (opts::PrintPseudoProbe) {
+    BC->ProbeDecoder.printGUID2FuncDescMap(outs());
+    BC->ProbeDecoder.printProbesForAllAddresses(outs());
+  }
+}
+
 void RewriteInstance::printSDTMarkers() {
   outs() << "BOLT-INFO: Number of SDT markers is " << BC->SDTMarkers.size()
          << "\n";
@@ -1546,6 +1585,8 @@ void RewriteInstance::readSpecialSections() {
   RelaDynSection = BC->getUniqueSectionByName(".rela.dyn");
   BuildIDSection = BC->getUniqueSectionByName(".note.gnu.build-id");
   SDTSection = BC->getUniqueSectionByName(".note.stapsdt");
+  PseudoProbeDescSection = BC->getUniqueSectionByName(".pseudo_probe_desc");
+  PseudoProbeSection = BC->getUniqueSectionByName(".pseudo_probe");
 
   if (ErrorOr<BinarySection &> BATSec =
           BC->getUniqueSectionByName(BoltAddressTranslation::SECTION_NAME)) {
@@ -1597,6 +1638,8 @@ void RewriteInstance::readSpecialSections() {
 
   parseSDTNotes();
 
+  parsePseudoProbe();
+
   // Read .dynamic/PT_DYNAMIC.
   readELFDynamic();
 }

bolt/src/RewriteInstance.h

@@ -331,6 +331,10 @@ private:
   /// Parse .note.stapsdt section
   void parseSDTNotes();
 
+  /// Parse .pseudo_probe_desc section and .pseudo_probe section
+  /// Setup Pseudo probe decoder
+  void parsePseudoProbe();
+
   /// Print all SDT markers
   void printSDTMarkers();
 
@@ -461,6 +465,15 @@ private:
   /// Contains information about statically defined tracing points
   ErrorOr<BinarySection &> SDTSection{std::errc::bad_address};
 
+  /// .pseudo_probe_desc section.
+  /// Contains information about pseudo probe description, like its related
+  /// function
+  ErrorOr<BinarySection &> PseudoProbeDescSection{std::errc::bad_address};
+
+  /// .pseudo_probe section.
+  /// Contains information about pseudo probe details, like its address
+  ErrorOr<BinarySection &> PseudoProbeSection{std::errc::bad_address};
+
   /// A reference to the build-id bytes in the original binary
   StringRef BuildID;