[PowerPC] Refactor getMinCallFrameSize / getMinCallArgumentsSize

As of r211495, the only remaining users of getMinCallFrameSize are in
core ABI code (LowerFormalParameter / LowerCall).  This is actually a
good thing, since the details of the parameter save area are ABI specific.

With the new ELFv2 ABI in particular, the rules defining the size of the
save area will become significantly more complex, so it wouldn't make
sense to implement those outside ABI code that has all required
information.

In preparation, this patch eliminates the getMinCallFrameSize (and
associated getMinCallArgumentsSize) routines, and inlines them into all
callers.  Note that since nearly all call arguments are constant, this
allows simplifying the inlined copies to a single line everywhere.

No change in generate code expected.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211497 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 20 insertions, 51 deletions

diff --git a/lib/Target/PowerPC/PPCFastISel.cpp b/lib/Target/PowerPC/PPCFastISel.cpp
index 1b4f12e2be..f3730e74c1 100644
--- a/lib/Target/PowerPC/PPCFastISel.cpp
+++ b/lib/Target/PowerPC/PPCFastISel.cpp
@@ -1199,7 +1199,8 @@ bool PPCFastISel::processCallArgs(SmallVectorImpl<Value*> &Args,
   CCState CCInfo(CC, IsVarArg, *FuncInfo.MF, TM, ArgLocs, *Context);
 
   // Reserve space for the linkage area on the stack.
-  CCInfo.AllocateStack(PPCFrameLowering::getLinkageSize(true, false), 8);
+  unsigned LinkageSize = PPCFrameLowering::getLinkageSize(true, false);
+  CCInfo.AllocateStack(LinkageSize, 8);
 
   CCInfo.AnalyzeCallOperands(ArgVTs, ArgFlags, CC_PPC64_ELF_FIS);
 
@@ -1227,8 +1228,7 @@ bool PPCFastISel::processCallArgs(SmallVectorImpl<Value*> &Args,
   // Because we cannot tell if this is needed on the caller side, we have to
   // conservatively assume that it is needed.  As such, make sure we have at
   // least enough stack space for the caller to store the 8 GPRs.
-  NumBytes = std::max(NumBytes,
-                      PPCFrameLowering::getMinCallFrameSize(true, false));
+  NumBytes = std::max(NumBytes, LinkageSize + 64);
 
   // Issue CALLSEQ_START.
   BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
diff --git a/lib/Target/PowerPC/PPCFrameLowering.cpp b/lib/Target/PowerPC/PPCFrameLowering.cpp
index ef4ea77bfc..65e9cf2b43 100644
--- a/lib/Target/PowerPC/PPCFrameLowering.cpp
+++ b/lib/Target/PowerPC/PPCFrameLowering.cpp
@@ -41,30 +41,6 @@ PPCFrameLowering::PPCFrameLowering(const PPCSubtarget &STI)
                           (STI.hasQPX() || STI.isBGQ()) ? 32 : 16, 0),
       Subtarget(STI) {}
 
-unsigned PPCFrameLowering::getMinCallArgumentsSize(bool isPPC64,
-                                                   bool isDarwinABI) {
-  // For the Darwin ABI / 64-bit SVR4 ABI:
-  // The prolog code of the callee may store up to 8 GPR argument registers to
-  // the stack, allowing va_start to index over them in memory if its varargs.
-  // Because we cannot tell if this is needed on the caller side, we have to
-  // conservatively assume that it is needed.  As such, make sure we have at
-  // least enough stack space for the caller to store the 8 GPRs.
-  if (isDarwinABI || isPPC64)
-    return 8 * (isPPC64 ? 8 : 4);
-
-  // 32-bit SVR4 ABI:
-  // There is no default stack allocated for the 8 first GPR arguments.
-  return 0;
-}
-
-/// getMinCallFrameSize - Return the minimum size a call frame can be using
-/// the PowerPC ABI.
-unsigned PPCFrameLowering::getMinCallFrameSize(bool isPPC64, bool isDarwinABI) {
-  // The call frame needs to be at least big enough for linkage and 8 args.
-  return PPCFrameLowering::getLinkageSize(isPPC64, isDarwinABI) +
-         PPCFrameLowering::getMinCallArgumentsSize(isPPC64, isDarwinABI);
-}
-
 // With the SVR4 ABI, callee-saved registers have fixed offsets on the stack.
 const PPCFrameLowering::SpillSlot *PPCFrameLowering::getCalleeSavedSpillSlots(
     unsigned &NumEntries) const {
diff --git a/lib/Target/PowerPC/PPCFrameLowering.h b/lib/Target/PowerPC/PPCFrameLowering.h
index ca1ca56d08..7a226f74e0 100644
--- a/lib/Target/PowerPC/PPCFrameLowering.h
+++ b/lib/Target/PowerPC/PPCFrameLowering.h
@@ -115,12 +115,8 @@ public:
     return 8;
   }
 
-  /// getMinCallArgumentsSize - Return the size of the minium PowerPC ABI
-  /// argument area.
-  static unsigned getMinCallArgumentsSize(bool isPPC64, bool isDarwinABI);
   const SpillSlot *
   getCalleeSavedSpillSlots(unsigned &NumEntries) const override;
-  static unsigned getMinCallFrameSize(bool isPPC64, bool isDarwinABI);
 };
 } // End llvm namespace
 
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 3b910ca01d..9a682af670 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -2215,7 +2215,8 @@ PPCTargetLowering::LowerFormalArguments_32SVR4(
                  getTargetMachine(), ArgLocs, *DAG.getContext());
 
   // Reserve space for the linkage area on the stack.
-  CCInfo.AllocateStack(PPCFrameLowering::getLinkageSize(false, false), PtrByteSize);
+  unsigned LinkageSize = PPCFrameLowering::getLinkageSize(false, false);
+  CCInfo.AllocateStack(LinkageSize, PtrByteSize);
 
   CCInfo.AnalyzeFormalArguments(Ins, CC_PPC32_SVR4);
 
@@ -2294,9 +2295,7 @@ PPCTargetLowering::LowerFormalArguments_32SVR4(
 
   // Area that is at least reserved in the caller of this function.
   unsigned MinReservedArea = CCByValInfo.getNextStackOffset();
-  MinReservedArea =
-    std::max(MinReservedArea,
-             PPCFrameLowering::getMinCallFrameSize(false, false));
+  MinReservedArea = std::max(MinReservedArea, LinkageSize);
 
   // Set the size that is at least reserved in caller of this function.  Tail
   // call optimized function's reserved stack space needs to be aligned so that
@@ -2420,7 +2419,8 @@ PPCTargetLowering::LowerFormalArguments_64SVR4(
                        (CallConv == CallingConv::Fast));
   unsigned PtrByteSize = 8;
 
-  unsigned ArgOffset = PPCFrameLowering::getLinkageSize(true, false);
+  unsigned LinkageSize = PPCFrameLowering::getLinkageSize(true, false);
+  unsigned ArgOffset = LinkageSize;
   // Area that is at least reserved in caller of this function.
   unsigned MinReservedArea = ArgOffset;
 
@@ -2657,9 +2657,7 @@ PPCTargetLowering::LowerFormalArguments_64SVR4(
   }
 
   // Area that is at least reserved in the caller of this function.
-  MinReservedArea =
-    std::max(MinReservedArea,
-             PPCFrameLowering::getMinCallFrameSize(true, false));
+  MinReservedArea = std::max(MinReservedArea, LinkageSize + 8 * PtrByteSize);
 
   // Set the size that is at least reserved in caller of this function.  Tail
   // call optimized functions' reserved stack space needs to be aligned so that
@@ -2719,7 +2717,8 @@ PPCTargetLowering::LowerFormalArguments_Darwin(
                        (CallConv == CallingConv::Fast));
   unsigned PtrByteSize = isPPC64 ? 8 : 4;
 
-  unsigned ArgOffset = PPCFrameLowering::getLinkageSize(isPPC64, true);
+  unsigned LinkageSize = PPCFrameLowering::getLinkageSize(isPPC64, true);
+  unsigned ArgOffset = LinkageSize;
   // Area that is at least reserved in caller of this function.
   unsigned MinReservedArea = ArgOffset;
 
@@ -3017,9 +3016,7 @@ PPCTargetLowering::LowerFormalArguments_Darwin(
   }
 
   // Area that is at least reserved in the caller of this function.
-  MinReservedArea =
-    std::max(MinReservedArea,
-             PPCFrameLowering::getMinCallFrameSize(isPPC64, true));
+  MinReservedArea = std::max(MinReservedArea, LinkageSize + 8 * PtrByteSize);
 
   // Set the size that is at least reserved in caller of this function.  Tail
   // call optimized functions' reserved stack space needs to be aligned so that
@@ -3965,7 +3962,8 @@ PPCTargetLowering::LowerCall_64SVR4(SDValue Chain, SDValue Callee,
   // Count how many bytes are to be pushed on the stack, including the linkage
   // area, and parameter passing area.  We start with at least 48 bytes, which
   // is reserved space for [SP][CR][LR][3 x unused].
-  unsigned NumBytes = PPCFrameLowering::getLinkageSize(true, false);
+  unsigned LinkageSize = PPCFrameLowering::getLinkageSize(true, false);
+  unsigned NumBytes = LinkageSize;
 
   // Add up all the space actually used.
   for (unsigned i = 0; i != NumOps; ++i) {
@@ -3986,8 +3984,7 @@ PPCTargetLowering::LowerCall_64SVR4(SDValue Chain, SDValue Callee,
   // Because we cannot tell if this is needed on the caller side, we have to
   // conservatively assume that it is needed.  As such, make sure we have at
   // least enough stack space for the caller to store the 8 GPRs.
-  NumBytes = std::max(NumBytes,
-                      PPCFrameLowering::getMinCallFrameSize(true, false));
+  NumBytes = std::max(NumBytes, LinkageSize + 8 * PtrByteSize);
 
   // Tail call needs the stack to be aligned.
   if (getTargetMachine().Options.GuaranteedTailCallOpt &&
@@ -4024,7 +4021,7 @@ PPCTargetLowering::LowerCall_64SVR4(SDValue Chain, SDValue Callee,
   // memory.  Also, if this is a vararg function, floating point operations
   // must be stored to our stack, and loaded into integer regs as well, if
   // any integer regs are available for argument passing.
-  unsigned ArgOffset = PPCFrameLowering::getLinkageSize(true, false);
+  unsigned ArgOffset = LinkageSize;
   unsigned GPR_idx = 0, FPR_idx = 0, VR_idx = 0;
 
   static const MCPhysReg GPR[] = {
@@ -4389,7 +4386,8 @@ PPCTargetLowering::LowerCall_Darwin(SDValue Chain, SDValue Callee,
   // Count how many bytes are to be pushed on the stack, including the linkage
   // area, and parameter passing area.  We start with 24/48 bytes, which is
   // prereserved space for [SP][CR][LR][3 x unused].
-  unsigned NumBytes = PPCFrameLowering::getLinkageSize(isPPC64, true);
+  unsigned LinkageSize = PPCFrameLowering::getLinkageSize(isPPC64, true);
+  unsigned NumBytes = LinkageSize;
 
   // Add up all the space actually used.
   // In 32-bit non-varargs calls, Altivec parameters all go at the end; usually
@@ -4428,8 +4426,7 @@ PPCTargetLowering::LowerCall_Darwin(SDValue Chain, SDValue Callee,
   // Because we cannot tell if this is needed on the caller side, we have to
   // conservatively assume that it is needed.  As such, make sure we have at
   // least enough stack space for the caller to store the 8 GPRs.
-  NumBytes = std::max(NumBytes,
-                      PPCFrameLowering::getMinCallFrameSize(isPPC64, true));
+  NumBytes = std::max(NumBytes, LinkageSize + 8 * PtrByteSize);
 
   // Tail call needs the stack to be aligned.
   if (getTargetMachine().Options.GuaranteedTailCallOpt &&
@@ -4470,7 +4467,7 @@ PPCTargetLowering::LowerCall_Darwin(SDValue Chain, SDValue Callee,
   // memory.  Also, if this is a vararg function, floating point operations
   // must be stored to our stack, and loaded into integer regs as well, if
   // any integer regs are available for argument passing.
-  unsigned ArgOffset = PPCFrameLowering::getLinkageSize(isPPC64, true);
+  unsigned ArgOffset = LinkageSize;
   unsigned GPR_idx = 0, FPR_idx = 0, VR_idx = 0;
 
   static const MCPhysReg GPR_32[] = {           // 32-bit registers.