[llvm] [llvm-profgen] Handle perf mmaps with page sizes larger than 4 KiB (PR #217887)

[via llvm-commits]

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@@ -594,30 +594,48 @@ void PerfScriptReader::updateBinaryAddress(const MMapEvent &Event) {
   if (PIDFilter && Event.PID != *PIDFilter)
     return;
 
-  // Drop the event if its image is loaded at the same address
-  if (Event.Address == Binary->getBaseAddress()) {
+  auto MMapContainsFileOffset = [&](uint64_t FileOffset) {
+    return Event.Offset == FileOffset ||
+           (Event.MemProtectionFlag.contains("x") &&
+            Event.Offset < FileOffset &&
+            FileOffset - Event.Offset < Event.Size);
+  };
+  const bool MMapContainsTextSegment =
+      MMapContainsFileOffset(Binary->getTextSegmentOffset());
+
+  // For user-space ELF, subtract the mmap file offset to get the runtime
+  // address corresponding to file offset zero. Kernel and COFF retain their
+  // existing mmap address semantics.
+  const uint64_t RuntimeBaseAddress = IsKernel || Binary->isCOFF()
+                                          ? Event.Address
+                                          : Event.Address - Event.Offset;
+
+  // Drop the event if its image has the same base address.
+  if ((IsKernel || MMapContainsTextSegment) &&
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HighW4y2H3ll wrote:

why is checking `IsKernel` and `MMapContainsTextSegment` necessary? shouldn't `RuntimeBaseAddress == Binary->getBaseAddress()` strict enough? This seems to be a bit redundent just to skip the `Binary->setBaseAddress(RuntimeBaseAddress);`

https://github.com/llvm/llvm-project/pull/217887