2 files changed, 14 insertions, 4 deletions
diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 1850a30a5d1..a305e3d3ab9 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -432,10 +432,13 @@ void CodeViewDebug::endModule() {
 }
 
 static void emitNullTerminatedSymbolName(MCStreamer &OS, StringRef S) {
-  // Microsoft's linker seems to have trouble with symbol names longer than
-  // 0xffd8 bytes.
-  S = S.substr(0, 0xffd8);
-  SmallString<32> NullTerminatedString(S);
+  // The maximum CV record length is 0xFF00. Most of the strings we emit appear
+  // after a fixed length portion of the record. The fixed length portion should
+  // always be less than 0xF00 (3840) bytes, so truncate the string so that the
+  // overall record size is less than the maximum allowed.
+  unsigned MaxFixedRecordLength = 0xF00;
+  SmallString<32> NullTerminatedString(
+      S.take_front(MaxRecordLength - MaxFixedRecordLength - 1));
   NullTerminatedString.push_back('\0');
   OS.EmitBytes(NullTerminatedString);
 }
diff --git a/llvm/lib/MC/MCCodeView.cpp b/llvm/lib/MC/MCCodeView.cpp
index ec5dc20a13e..ac1acc08b0c 100644
--- a/llvm/lib/MC/MCCodeView.cpp
+++ b/llvm/lib/MC/MCCodeView.cpp
@@ -358,6 +358,13 @@ void CodeViewContext::encodeInlineLineTable(MCAsmLayout &Layout,
   SmallVectorImpl<char> &Buffer = Frag.getContents();
   Buffer.clear(); // Clear old contents if we went through relaxation.
   for (const MCCVLineEntry &Loc : Locs) {
+    // Exit early if our line table would produce an oversized InlineSiteSym
+    // record. Account for the ChangeCodeLength annotation emitted after the
+    // loop ends.
+    size_t MaxBufferSize = MaxRecordLength - sizeof(InlineSiteSym::Hdr) - 8;
+    if (Buffer.size() >= MaxBufferSize)
+      break;
+
     if (Loc.getFunctionId() == Frag.SiteFuncId) {
       CurSourceLoc.File = Loc.getFileNum();
       CurSourceLoc.Line = Loc.getLine();