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/IntrinsicLowering.cpp b/llvm/lib/CodeGen/IntrinsicLowering.cpp
index 5b895ff..47a9f64 100644
--- a/llvm/lib/CodeGen/IntrinsicLowering.cpp
+++ b/llvm/lib/CodeGen/IntrinsicLowering.cpp
@@ -424,6 +424,13 @@
break;
}
+ case Intrinsic::get_dynamic_area_offset:
+ errs() << "WARNING: this target does not support the custom llvm.get."
+ "dynamic.area.offset. It is being lowered to a constant 0\n";
+ // Just lower it to a constant 0 because for most targets
+ // @llvm.get.dynamic.area.offset is lowered to zero.
+ CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 0));
+ break;
case Intrinsic::returnaddress:
case Intrinsic::frameaddress:
errs() << "WARNING: this target does not support the llvm."
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;
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index d880bcf..38b8bce 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -4928,6 +4928,21 @@
DAG.setRoot(DAG.getNode(ISD::STACKRESTORE, sdl, MVT::Other, getRoot(), Res));
return nullptr;
}
+ case Intrinsic::get_dynamic_area_offset: {
+ SDValue Op = getRoot();
+ EVT PtrTy = TLI.getPointerTy(DAG.getDataLayout());
+ EVT ResTy = TLI.getValueType(DAG.getDataLayout(), I.getType());
+ // Result type for @llvm.get.dynamic.area.offset should match PtrTy for
+ // target.
+ if (PtrTy != ResTy)
+ report_fatal_error("Wrong result type for @llvm.get.dynamic.area.offset"
+ " intrinsic!");
+ Res = DAG.getNode(ISD::GET_DYNAMIC_AREA_OFFSET, sdl, DAG.getVTList(ResTy),
+ Op);
+ DAG.setRoot(Op);
+ setValue(&I, Res);
+ return nullptr;
+ }
case Intrinsic::stackprotector: {
// Emit code into the DAG to store the stack guard onto the stack.
MachineFunction &MF = DAG.getMachineFunction();
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
index 195b484..a6f9699 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
@@ -310,6 +310,7 @@
case ISD::LIFETIME_END: return "lifetime.end";
case ISD::GC_TRANSITION_START: return "gc_transition.start";
case ISD::GC_TRANSITION_END: return "gc_transition.end";
+ case ISD::GET_DYNAMIC_AREA_OFFSET: return "get.dynamic.area.offset";
// Bit manipulation
case ISD::BITREVERSE: return "bitreverse";
diff --git a/llvm/lib/CodeGen/TargetLoweringBase.cpp b/llvm/lib/CodeGen/TargetLoweringBase.cpp
index e348095..69c1308 100644
--- a/llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -840,6 +840,9 @@
setOperationAction(ISD::SIGN_EXTEND_VECTOR_INREG, VT, Expand);
setOperationAction(ISD::ZERO_EXTEND_VECTOR_INREG, VT, Expand);
}
+
+ // For most targets @llvm.get.dynamic.area.offest just returns 0.
+ setOperationAction(ISD::GET_DYNAMIC_AREA_OFFSET, VT, Expand);
}
// Most targets ignore the @llvm.prefetch intrinsic.