Introduce new @llvm.get.dynamic.area.offset.i{32, 64} intrinsics.
The @llvm.get.dynamic.area.offset.* intrinsic family is used to get the offset
from native stack pointer to the address of the most recent dynamic alloca on
the caller's stack. These intrinsics are intendend for use in combination with
@llvm.stacksave and @llvm.restore to get a pointer to the most recent dynamic
alloca. This is useful, for example, for AddressSanitizer's stack unpoisoning
routines.
Patch by Max Ostapenko.
Differential Revision: http://reviews.llvm.org/D14983
llvm-svn: 254404
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index c581052..8238cde 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -1213,6 +1213,10 @@
case ISD::STACKSAVE:
Action = TLI.getOperationAction(Node->getOpcode(), MVT::Other);
break;
+ case ISD::GET_DYNAMIC_AREA_OFFSET:
+ Action = TLI.getOperationAction(Node->getOpcode(),
+ Node->getValueType(0));
+ break;
case ISD::VAARG:
Action = TLI.getOperationAction(Node->getOpcode(),
Node->getValueType(0));
@@ -3295,6 +3299,10 @@
Results.push_back(Node->getOperand(0));
}
break;
+ case ISD::GET_DYNAMIC_AREA_OFFSET:
+ Results.push_back(DAG.getConstant(0, dl, Node->getValueType(0)));
+ Results.push_back(Results[0].getValue(0));
+ break;
case ISD::FCOPYSIGN:
Results.push_back(ExpandFCOPYSIGN(Node));
break;