[PATCH] D157734: [x86][harden-sls] insert int3 trap after __x86_return_thunk jump

[Nick Desaulniers via Phabricator via llvm-commits]

nickdesaulniers created this revision.
Herald added subscribers: pengfei, hiraditya.
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nickdesaulniers requested review of this revision.
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This ensures that -mharden-sls=all -mfunction-return=thunk-extern
compose well.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D157734

Files:
  llvm/lib/Target/X86/X86AsmPrinter.cpp


Index: llvm/lib/Target/X86/X86AsmPrinter.cpp
===================================================================
--- llvm/lib/Target/X86/X86AsmPrinter.cpp
+++ llvm/lib/Target/X86/X86AsmPrinter.cpp
@@ -441,7 +441,11 @@
   if (Subtarget->hardenSlsRet() || Subtarget->hardenSlsIJmp()) {
     auto I = MBB.getLastNonDebugInstr();
     if (I != MBB.end()) {
-      if ((Subtarget->hardenSlsRet() && isSimpleReturn(*I)) ||
+      if ((Subtarget->hardenSlsRet() &&
+           (isSimpleReturn(*I) ||
+            (I->getOpcode() == X86::TAILJMPd && I->getOperand(0).isSymbol() &&
+             !strcmp(I->getOperand(0).getSymbolName(),
+                     "__x86_return_thunk")))) ||
           (Subtarget->hardenSlsIJmp() && isIndirectBranchOrTailCall(*I))) {
         MCInst TmpInst;
         TmpInst.setOpcode(X86::INT3);


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