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-rw-r--r--llvm/include/llvm/CodeGen/CallingConvLower.h7
-rw-r--r--llvm/include/llvm/Target/TargetLowering.h12
-rw-r--r--llvm/lib/CodeGen/SelectionDAG/CallingConvLower.cpp15
-rw-r--r--llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp60
-rw-r--r--llvm/lib/Target/X86/X86ISelLowering.cpp11
-rw-r--r--llvm/lib/Target/X86/X86ISelLowering.h6
6 files changed, 111 insertions, 0 deletions
diff --git a/llvm/include/llvm/CodeGen/CallingConvLower.h b/llvm/include/llvm/CodeGen/CallingConvLower.h
index 5e730fc12cc..45a2757d378 100644
--- a/llvm/include/llvm/CodeGen/CallingConvLower.h
+++ b/llvm/include/llvm/CodeGen/CallingConvLower.h
@@ -183,6 +183,13 @@ public:
void AnalyzeReturn(const SmallVectorImpl<ISD::OutputArg> &Outs,
CCAssignFn Fn);
+ /// CheckReturn - Analyze the return values of a function, returning
+ /// true if the return can be performed without sret-demotion, and
+ /// false otherwise.
+ bool CheckReturn(const SmallVectorImpl<EVT> &OutTys,
+ const SmallVectorImpl<ISD::ArgFlagsTy> &ArgsFlags,
+ CCAssignFn Fn);
+
/// AnalyzeCallOperands - Analyze the outgoing arguments to a call,
/// incorporating info about the passed values into this state.
void AnalyzeCallOperands(const SmallVectorImpl<ISD::OutputArg> &Outs,
diff --git a/llvm/include/llvm/Target/TargetLowering.h b/llvm/include/llvm/Target/TargetLowering.h
index 8bc39d0b2ce..1526a0de0c5 100644
--- a/llvm/include/llvm/Target/TargetLowering.h
+++ b/llvm/include/llvm/Target/TargetLowering.h
@@ -1167,6 +1167,18 @@ public:
return SDValue(); // this is here to silence compiler errors
}
+ /// CanLowerReturn - This hook should be implemented to check whether the
+ /// return values described by the Outs array can fit into the return
+ /// registers. If false is returned, an sret-demotion is performed.
+ ///
+ virtual bool CanLowerReturn(CallingConv::ID CallConv, bool isVarArg,
+ const SmallVectorImpl<EVT> &OutTys,
+ const SmallVectorImpl<ISD::ArgFlagsTy> &ArgsFlags,
+ SelectionDAG &DAG)
+ {
+ // Return true by default to get preexisting behavior.
+ return true;
+ }
/// LowerReturn - This hook must be implemented to lower outgoing
/// return values, described by the Outs array, into the specified
/// DAG. The implementation should return the resulting token chain
diff --git a/llvm/lib/CodeGen/SelectionDAG/CallingConvLower.cpp b/llvm/lib/CodeGen/SelectionDAG/CallingConvLower.cpp
index fbe40b67863..38839c44131 100644
--- a/llvm/lib/CodeGen/SelectionDAG/CallingConvLower.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/CallingConvLower.cpp
@@ -77,6 +77,21 @@ CCState::AnalyzeFormalArguments(const SmallVectorImpl<ISD::InputArg> &Ins,
}
}
+/// CheckReturn - Analyze the return values of a function, returning true if
+/// the return can be performed without sret-demotion, and false otherwise.
+bool CCState::CheckReturn(const SmallVectorImpl<EVT> &OutTys,
+ const SmallVectorImpl<ISD::ArgFlagsTy> &ArgsFlags,
+ CCAssignFn Fn) {
+ // Determine which register each value should be copied into.
+ for (unsigned i = 0, e = OutTys.size(); i != e; ++i) {
+ EVT VT = OutTys[i];
+ ISD::ArgFlagsTy ArgFlags = ArgsFlags[i];
+ if (Fn(i, VT, VT, CCValAssign::Full, ArgFlags, *this))
+ return false;
+ }
+ return true;
+}
+
/// AnalyzeReturn - Analyze the returned values of a return,
/// incorporating info about the result values into this state.
void CCState::AnalyzeReturn(const SmallVectorImpl<ISD::OutputArg> &Outs,
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
index c0d2a4d39a3..1ff1cd30f24 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
@@ -947,6 +947,58 @@ SDValue SelectionDAGLowering::getValue(const Value *V) {
return RFV.getCopyFromRegs(DAG, getCurDebugLoc(), Chain, NULL);
}
+/// Get the EVTs and ArgFlags collections that represent the return type
+/// of the given function. This does not require a DAG or a return value, and
+/// is suitable for use before any DAGs for the function are constructed.
+static void getReturnInfo(const Function* F, SmallVectorImpl<EVT> &OutVTs,
+ SmallVectorImpl<ISD::ArgFlagsTy> &OutFlags,
+ TargetLowering &TLI) {
+ const Type* ReturnType = F->getReturnType();
+
+ SmallVector<EVT, 4> ValueVTs;
+ ComputeValueVTs(TLI, ReturnType, ValueVTs);
+ unsigned NumValues = ValueVTs.size();
+ if ( NumValues == 0 ) return;
+
+ for (unsigned j = 0, f = NumValues; j != f; ++j) {
+ EVT VT = ValueVTs[j];
+ ISD::NodeType ExtendKind = ISD::ANY_EXTEND;
+
+ if (F->paramHasAttr(0, Attribute::SExt))
+ ExtendKind = ISD::SIGN_EXTEND;
+ else if (F->paramHasAttr(0, Attribute::ZExt))
+ ExtendKind = ISD::ZERO_EXTEND;
+
+ // FIXME: C calling convention requires the return type to be promoted to
+ // at least 32-bit. But this is not necessary for non-C calling
+ // conventions. The frontend should mark functions whose return values
+ // require promoting with signext or zeroext attributes.
+ if (ExtendKind != ISD::ANY_EXTEND && VT.isInteger()) {
+ EVT MinVT = TLI.getRegisterType(F->getContext(), MVT::i32);
+ if (VT.bitsLT(MinVT))
+ VT = MinVT;
+ }
+
+ unsigned NumParts = TLI.getNumRegisters(F->getContext(), VT);
+ EVT PartVT = TLI.getRegisterType(F->getContext(), VT);
+ // 'inreg' on function refers to return value
+ ISD::ArgFlagsTy Flags = ISD::ArgFlagsTy();
+ if (F->paramHasAttr(0, Attribute::InReg))
+ Flags.setInReg();
+
+ // Propagate extension type if any
+ if (F->paramHasAttr(0, Attribute::SExt))
+ Flags.setSExt();
+ else if (F->paramHasAttr(0, Attribute::ZExt))
+ Flags.setZExt();
+
+ for (unsigned i = 0; i < NumParts; ++i)
+ {
+ OutVTs.push_back(PartVT);
+ OutFlags.push_back(Flags);
+ }
+ }
+}
void SelectionDAGLowering::visitRet(ReturnInst &I) {
SDValue Chain = getControlRoot();
@@ -5758,6 +5810,14 @@ void SelectionDAGISel::LowerArguments(BasicBlock *LLVMBB) {
DebugLoc dl = SDL->getCurDebugLoc();
const TargetData *TD = TLI.getTargetData();
+ // Check whether the function can return without sret-demotion.
+ SmallVector<EVT, 4> OutVTs;
+ SmallVector<ISD::ArgFlagsTy, 4> OutsFlags;
+ getReturnInfo(&F, OutVTs, OutsFlags, TLI);
+ // For now, assert and bail out if it can't.
+ assert(TLI.CanLowerReturn(F.getCallingConv(), F.isVarArg(), OutVTs, OutsFlags,
+ DAG) && "Cannot fit return value in registers!");
+
// Set up the incoming argument description vector.
SmallVector<ISD::InputArg, 16> Ins;
unsigned Idx = 1;
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 86ec9f2f17a..3b11ef4e369 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -1087,6 +1087,17 @@ unsigned X86TargetLowering::getFunctionAlignment(const Function *F) const {
#include "X86GenCallingConv.inc"
+bool
+X86TargetLowering::CanLowerReturn(CallingConv::ID CallConv, bool isVarArg,
+ const SmallVectorImpl<EVT> &OutTys,
+ const SmallVectorImpl<ISD::ArgFlagsTy> &ArgsFlags,
+ SelectionDAG &DAG) {
+ SmallVector<CCValAssign, 16> RVLocs;
+ CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
+ RVLocs, *DAG.getContext());
+ return CCInfo.CheckReturn(OutTys, ArgsFlags, RetCC_X86);
+}
+
SDValue
X86TargetLowering::LowerReturn(SDValue Chain,
CallingConv::ID CallConv, bool isVarArg,
diff --git a/llvm/lib/Target/X86/X86ISelLowering.h b/llvm/lib/Target/X86/X86ISelLowering.h
index 7b59b81f81a..0755284a9e2 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.h
+++ b/llvm/lib/Target/X86/X86ISelLowering.h
@@ -699,6 +699,12 @@ namespace llvm {
const SmallVectorImpl<ISD::OutputArg> &Outs,
DebugLoc dl, SelectionDAG &DAG);
+ virtual bool
+ CanLowerReturn(CallingConv::ID CallConv, bool isVarArg,
+ const SmallVectorImpl<EVT> &OutTys,
+ const SmallVectorImpl<ISD::ArgFlagsTy> &ArgsFlags,
+ SelectionDAG &DAG);
+
void ReplaceATOMIC_BINARY_64(SDNode *N, SmallVectorImpl<SDValue> &Results,
SelectionDAG &DAG, unsigned NewOp);
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