ARM:

Removed extra stack frame object for fixed byval arguments,
VarArgsStyleRegisters invocation was reworked due to some improper usage in
past. PR14099 also demonstrates it.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166273 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 49 insertions, 12 deletions

diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index b2eb578487..8de2387234 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -2554,7 +2554,8 @@ ARMTargetLowering::VarArgStyleRegisters(CCState &CCInfo, SelectionDAG &DAG,
                                         DebugLoc dl, SDValue &Chain,
                                         const Value *OrigArg,
                                         unsigned OffsetFromOrigArg,
-                                        unsigned ArgOffset) const {
+                                        unsigned ArgOffset,
+                                        bool ForceMutable) const {
   MachineFunction &MF = DAG.getMachineFunction();
   MachineFrameInfo *MFI = MF.getFrameInfo();
   ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
@@ -2603,7 +2604,8 @@ ARMTargetLowering::VarArgStyleRegisters(CCState &CCInfo, SelectionDAG &DAG,
                           &MemOps[0], MemOps.size());
   } else
     // This will point to the next argument passed via stack.
-    AFI->setVarArgsFrameIndex(MFI->CreateFixedObject(4, ArgOffset, true));
+    AFI->setVarArgsFrameIndex(
+        MFI->CreateFixedObject(4, ArgOffset, !ForceMutable));
 }
 
 SDValue
@@ -2729,15 +2731,20 @@ ARMTargetLowering::LowerFormalArguments(SDValue Chain,
           // Since they could be overwritten by lowering of arguments in case of
           // a tail call.
           if (Flags.isByVal()) {
-            unsigned VARegSize, VARegSaveSize;
-            computeRegArea(CCInfo, MF, VARegSize, VARegSaveSize);
-            VarArgStyleRegisters(CCInfo, DAG,
-                                 dl, Chain, CurOrigArg, Ins[VA.getValNo()].PartOffset, 0);
-            unsigned Bytes = Flags.getByValSize() - VARegSize;
-            if (Bytes == 0) Bytes = 1; // Don't create zero-sized stack objects.
-            int FI = MFI->CreateFixedObject(Bytes,
-                                            VA.getLocMemOffset(), false);
-            InVals.push_back(DAG.getFrameIndex(FI, getPointerTy()));
+            ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+            if (!AFI->getVarArgsFrameIndex()) {
+              VarArgStyleRegisters(CCInfo, DAG,
+                                   dl, Chain, CurOrigArg,
+                                   Ins[VA.getValNo()].PartOffset,
+                                   VA.getLocMemOffset(),
+                                   true /*force mutable frames*/);
+              int VAFrameIndex = AFI->getVarArgsFrameIndex();
+              InVals.push_back(DAG.getFrameIndex(VAFrameIndex, getPointerTy()));
+            } else {
+              int FI = MFI->CreateFixedObject(Flags.getByValSize(),
+                                              VA.getLocMemOffset(), false);
+              InVals.push_back(DAG.getFrameIndex(FI, getPointerTy()));              
+            }
           } else {
             int FI = MFI->CreateFixedObject(VA.getLocVT().getSizeInBits()/8,
                                             VA.getLocMemOffset(), true);
diff --git a/lib/Target/ARM/ARMISelLowering.h b/lib/Target/ARM/ARMISelLowering.h
index 9acab0b083..4eb3b2cb51 100644
--- a/lib/Target/ARM/ARMISelLowering.h
+++ b/lib/Target/ARM/ARMISelLowering.h
@@ -469,7 +469,8 @@ namespace llvm {
                               DebugLoc dl, SDValue &Chain,
                               const Value *OrigArg,
                               unsigned OffsetFromOrigArg,
-                              unsigned ArgOffset)
+                              unsigned ArgOffset,
+                              bool ForceMutable = false)
       const;
 
     void computeRegArea(CCState &CCInfo, MachineFunction &MF,
diff --git a/test/CodeGen/ARM/2012-10-18-PR14099-ByvalFrameAddress.ll b/test/CodeGen/ARM/2012-10-18-PR14099-ByvalFrameAddress.ll
new file mode 100644
index 0000000000..fcc6a7f7e9
--- /dev/null
+++ b/test/CodeGen/ARM/2012-10-18-PR14099-ByvalFrameAddress.ll
@@ -0,0 +1,29 @@
+; RUN: llc < %s -mtriple=armv7-linux-gnueabi | FileCheck %s
+
+%struct.s = type { [4 x i32] }
+@v = constant %struct.s zeroinitializer; 
+
+declare void @f(%struct.s* %p);
+
+; CHECK: t:
+define void @t(i32 %a, %struct.s* byval %s) nounwind {
+entry:
+
+; Here we need to only check proper start address of restored %s argument.
+; CHECK:      sub     sp, sp, #16
+; CHECK:      push    {r11, lr}
+; CHECK:      add     r0, sp, #12
+; CHECK:      stm     r0, {r1, r2, r3}
+; CHECK:      add     r0, sp, #12
+; CHECK-NEXT: bl f
+  call void @f(%struct.s* %s)
+  ret void
+}
+
+; CHECK: caller:
+define void @caller() {
+
+; CHECK:      ldm     r0, {r1, r2, r3}
+  call void @t(i32 0, %struct.s* @v);
+  ret void
+}