[BOLT] Detect Linux kernel version if the binary is a Linux kernel

Use struct instead of tuple to represent Linux kernel version

Author: FLZ101

bolt/include/bolt/Core/BinaryContext.h

@@ -180,6 +180,34 @@ struct JournalingStreams {
 Error createNonFatalBOLTError(const Twine &S);
 Error createFatalBOLTError(const Twine &S);
 
+/// Linux kernel version
+struct LKVersion {
+  LKVersion() {}
+  LKVersion(unsigned Major, unsigned Minor, unsigned Rev)
+      : Major(Major), Minor(Minor), Rev(Rev) {}
+
+  bool operator<(const LKVersion &Other) const {
+    return std::make_tuple(Major, Minor, Rev) <
+           std::make_tuple(Other.Major, Other.Minor, Other.Rev);
+  }
+
+  bool operator>(const LKVersion &Other) const { return Other < *this; }
+
+  bool operator<=(const LKVersion &Other) const { return !(*this > Other); }
+
+  bool operator>=(const LKVersion &Other) const { return !(*this < Other); }
+
+  bool operator==(const LKVersion &Other) const {
+    return Major == Other.Major && Minor == Other.Minor && Rev == Other.Rev;
+  }
+
+  bool operator!=(const LKVersion &Other) const { return !(*this == Other); }
+
+  unsigned Major{0};
+  unsigned Minor{0};
+  unsigned Rev{0};
+};
+
 class BinaryContext {
   BinaryContext() = delete;
 
@@ -670,8 +698,7 @@ class BinaryContext {
   /// Indicates if the binary is Linux kernel.
   bool IsLinuxKernel{false};
 
-  /// Linux kernel version (major, minor, reversion)
-  std::tuple<unsigned, unsigned, unsigned> LinuxKernelVersion;
+  LKVersion LinuxKernelVersion;
 
   /// Indicates if relocations are available for usage.
   bool HasRelocations{false};

bolt/lib/Rewrite/RewriteInstance.cpp

@@ -1045,7 +1045,7 @@ void RewriteInstance::discoverFileObjects() {
         unsigned Major = std::stoi(Match[2].str());
         unsigned Minor = std::stoi(Match[3].str());
         unsigned Rev = Match.size() > 5 ? std::stoi(Match[5].str()) : 0;
-        BC->LinuxKernelVersion = std::make_tuple(Major, Minor, Rev);
+        BC->LinuxKernelVersion = LKVersion(Major, Minor, Rev);
         BC->outs() << "BOLT-INFO: Linux kernel version is " << Match[1].str();
       }
     }
@@ -1225,7 +1225,7 @@ void RewriteInstance::discoverFileObjects() {
     PreviousFunction = BF;
   }
 
-  if (BC->IsLinuxKernel && !std::get<0>(BC->LinuxKernelVersion))
+  if (BC->IsLinuxKernel && !BC->LinuxKernelVersion.Major)
     BC->errs() << "BOLT-WARNING: Linux kernel version is unknown\n";
 
   // Read dynamic relocation first as their presence affects the way we process

bolt/unittests/Core/BinaryContext.cpp

@@ -218,3 +218,17 @@ TEST_P(BinaryContextTester, BaseAddressSegmentsSmallerThanAlignment) {
   ASSERT_TRUE(BaseAddress.has_value());
   ASSERT_EQ(*BaseAddress, 0xaaaaaaaa0000ULL);
 }
+
+TEST(BinaryContextTester, LKVersion) {
+  LKVersion V1;
+  LKVersion V2(5, 9, 15);
+  LKVersion V3(6, 12, 1);
+
+  V1 = V3;
+  ASSERT_TRUE(V1 == V3);
+  ASSERT_TRUE(V2 != V3);
+  ASSERT_TRUE(V2 < V3);
+  ASSERT_TRUE(V2 <= V3);
+  ASSERT_TRUE(V3 > V2);
+  ASSERT_TRUE(V3 >= V2);
+}