[DebugInfo] Exclude memory location values as parameter entry values

Abandon describing of loaded values due to safety concerns. Loaded
values are described as derefed memory location at caller point.
At callee we can unintentionally change that memory location which
would lead to different entry being printed value before and after
the memory location clobbering. This problem is described in
llvm.org/PR43343.

Patch by Nikola Prica

Differential Revision: https://reviews.llvm.org/D67717

llvm-svn: 373089

1 files changed, 0 insertions, 12 deletions

diff --git a/llvm/lib/CodeGen/TargetInstrInfo.cpp b/llvm/lib/CodeGen/TargetInstrInfo.cpp
index 0e9eb77ea26..2108fc6fecf 100644
--- a/llvm/lib/CodeGen/TargetInstrInfo.cpp
+++ b/llvm/lib/CodeGen/TargetInstrInfo.cpp
@@ -1133,18 +1133,6 @@ TargetInstrInfo::describeLoadedValue(const MachineInstr &MI) const {
   } else if (MI.isMoveImmediate()) {
     Op = &MI.getOperand(1);
     return ParamLoadedValue(*Op, Expr);
-  } else if (MI.hasOneMemOperand()) {
-    int64_t Offset;
-    const auto &TRI = MF->getSubtarget().getRegisterInfo();
-    const auto &TII = MF->getSubtarget().getInstrInfo();
-    const MachineOperand *BaseOp;
-
-    if (!TII->getMemOperandWithOffset(MI, BaseOp, Offset, TRI))
-      return None;
-
-    Expr = DIExpression::prepend(Expr, DIExpression::DerefAfter, Offset);
-    Op = BaseOp;
-    return ParamLoadedValue(*Op, Expr);
   }
 
   return None;