[PATCH] D110365: [llvm][profile] Do not read padding when printing build IDs

[Leonard Chan via Phabricator via llvm-commits]

leonardchan updated this revision to Diff 374668.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D110365/new/

https://reviews.llvm.org/D110365

Files:
  llvm/lib/ProfileData/InstrProfReader.cpp


Index: llvm/lib/ProfileData/InstrProfReader.cpp
===================================================================
--- llvm/lib/ProfileData/InstrProfReader.cpp
+++ llvm/lib/ProfileData/InstrProfReader.cpp
@@ -527,8 +527,24 @@
 
   OS << "Binary IDs: \n";
   const uint8_t *BI = BinaryIdsStart;
-  while (BI < BinaryIdsStart + BinaryIdsSize) {
-    uint64_t BinaryIdLen = swap(*reinterpret_cast<const uint64_t *>(BI));
+  const uint8_t *BIEnd = BinaryIdsStart + BinaryIdsSize;
+  while (BI < BIEnd) {
+    uint64_t BinaryIdLen = 0;
+    auto Remaining = BIEnd - BI;
+
+    // If we do not have enough to read a uint64_t, then this remaining data
+    // must be zero-padding. If it's not padded, then the data must be corrupted
+    // somehow. In case of misalignment, we can use memcpy() for safe reads.
+    if (Remaining < sizeof(BinaryIdLen)) {
+      memcpy(&BinaryIdLen, BI, Remaining);
+      if (!BinaryIdLen)
+        return success();
+      return make_error<InstrProfError>(instrprof_error::malformed);
+    }
+
+    memcpy(&BinaryIdLen, BI, sizeof(BinaryIdLen));
+    BinaryIdLen = swap(BinaryIdLen);
+
     // Increment by binary id length data type size.
     BI += sizeof(BinaryIdLen);
     if (BI > (const uint8_t *)DataBuffer->getBufferEnd())


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