Refactor how MCCFIInstructions are created.

Give MCCFIInstruction a single, private constructor and add helper static
methods that create each type of cfi instruction. This is is preparation
for changing its representation. The representation with a pair
MachineLocations older than MC and has been abused quiet a bit to support
more cfi instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168532 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 124 insertions, 42 deletions

diff --git a/include/llvm/MC/MCDwarf.h b/include/llvm/MC/MCDwarf.h
index 6fa41ae..77b5f1c 100644
--- a/include/llvm/MC/MCDwarf.h
+++ b/include/llvm/MC/MCDwarf.h
@@ -275,28 +275,100 @@ namespace llvm {
     MachineLocation Destination;
     MachineLocation Source;
     std::vector<char> Values;
+    MCCFIInstruction(OpType Op, MCSymbol *L, const MachineLocation &D,
+                     const MachineLocation &S, StringRef V) :
+      Operation(Op), Label(L), Destination(D), Source(S),
+      Values(V.begin(), V.end()) {
+    }
+
   public:
-    MCCFIInstruction(OpType Op, MCSymbol *L)
-      : Operation(Op), Label(L) {
-      assert(Op == RememberState || Op == RestoreState);
+    static MCCFIInstruction
+    createCFIOffset(MCSymbol *L, unsigned Register, int Offset) {
+      MachineLocation Dest(Register, Offset);
+      MachineLocation Source(Register, Offset);
+
+      MCCFIInstruction Ret(Move, L, Dest, Source, "");
+      return Ret;
+    }
+
+    static MCCFIInstruction
+    createDefCfaRegister(MCSymbol *L, unsigned Register) {
+      MachineLocation Dest(Register);
+      MachineLocation Source(MachineLocation::VirtualFP);
+      MCCFIInstruction Ret(Move, L, Dest, Source, "");
+      return Ret;
     }
-    MCCFIInstruction(OpType Op, MCSymbol *L, unsigned Register)
-      : Operation(Op), Label(L), Destination(Register) {
-      assert(Op == SameValue || Op == Restore || Op == Undefined);
+
+    static MCCFIInstruction createDefCfaOffset(MCSymbol *L, int Offset) {
+      MachineLocation Dest(MachineLocation::VirtualFP);
+      MachineLocation Source(MachineLocation::VirtualFP, -Offset);
+      MCCFIInstruction Ret(Move, L, Dest, Source, "");
+      return Ret;
     }
-    MCCFIInstruction(MCSymbol *L, const MachineLocation &D,
-                     const MachineLocation &S)
-      : Operation(Move), Label(L), Destination(D), Source(S) {
+
+    static MCCFIInstruction
+    createDefCfa(MCSymbol *L, unsigned Register, int Offset) {
+      MachineLocation Dest(MachineLocation::VirtualFP);
+      MachineLocation Source(Register, -Offset);
+      MCCFIInstruction Ret(Move, L, Dest, Source, "");
+      return Ret;
     }
-    MCCFIInstruction(OpType Op, MCSymbol *L, const MachineLocation &D,
-                     const MachineLocation &S)
-      : Operation(Op), Label(L), Destination(D), Source(S) {
-      assert(Op == RelMove);
+
+    static MCCFIInstruction createUndefined(MCSymbol *L, unsigned Register) {
+      MachineLocation Dummy;
+      MachineLocation Dest(Register);
+      MCCFIInstruction Ret(Undefined, L, Dest, Dummy, "");
+      return Ret;
+    }
+
+    static MCCFIInstruction createRestore(MCSymbol *L, unsigned Register) {
+      MachineLocation Dummy;
+      MachineLocation Dest(Register);
+      MCCFIInstruction Ret(Restore, L, Dest, Dummy, "");
+      return Ret;
     }
-    MCCFIInstruction(OpType Op, MCSymbol *L, StringRef Vals)
-      : Operation(Op), Label(L), Values(Vals.begin(), Vals.end()) {
-      assert(Op == Escape);
+
+    static MCCFIInstruction createSameValue(MCSymbol *L, unsigned Register) {
+      MachineLocation Dummy;
+      MachineLocation Dest(Register);
+      MCCFIInstruction Ret(SameValue, L, Dest, Dummy, "");
+      return Ret;
+    }
+
+    static MCCFIInstruction createRestoreState(MCSymbol *L) {
+      MachineLocation Dummy;
+      MCCFIInstruction Ret(RestoreState, L, Dummy, Dummy, "");
+      return Ret;
+    }
+
+    static MCCFIInstruction createRememberState(MCSymbol *L) {
+      MachineLocation Dummy;
+      MCCFIInstruction Ret(RememberState, L, Dummy, Dummy, "");
+      return Ret;
+    }
+
+    static MCCFIInstruction
+    createRelOffset(MCSymbol *L, unsigned Register, int Offset) {
+      MachineLocation Dest(Register, Offset);
+      MachineLocation Source(Register, Offset);
+      MCCFIInstruction Ret(RelMove, L, Dest, Source, "");
+      return Ret;
+    }
+
+    static MCCFIInstruction
+    createAdjustCfaOffset(MCSymbol *L, int Adjustment) {
+      MachineLocation Dest(MachineLocation::VirtualFP);
+      MachineLocation Source(MachineLocation::VirtualFP, Adjustment);
+      MCCFIInstruction Ret(RelMove, L, Dest, Source, "");
+      return Ret;
     }
+
+    static MCCFIInstruction createEscape(MCSymbol *L, StringRef Vals) {
+      MachineLocation Dummy;
+      MCCFIInstruction Ret(Escape, L, Dummy, Dummy, Vals);
+      return Ret;
+    }
+
     OpType getOperation() const { return Operation; }
     MCSymbol *getLabel() const { return Label; }
     const MachineLocation &getDestination() const { return Destination; }
diff --git a/lib/MC/MCDwarf.cpp b/lib/MC/MCDwarf.cpp
index 85b47fe..c9b21e3 100644
--- a/lib/MC/MCDwarf.cpp
+++ b/lib/MC/MCDwarf.cpp
@@ -1264,8 +1264,21 @@ const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
       TranslateMachineLocation(MRI, Moves[i].getDestination());
     const MachineLocation &Src =
       TranslateMachineLocation(MRI, Moves[i].getSource());
-    MCCFIInstruction Inst(Label, Dst, Src);
-    Instructions.push_back(Inst);
+
+    if (Dst.isReg()) {
+      assert(Dst.getReg() == MachineLocation::VirtualFP);
+      assert(!Src.isReg());
+      MCCFIInstruction Inst =
+        MCCFIInstruction::createDefCfa(Label, Src.getReg(), -Src.getOffset());
+      Instructions.push_back(Inst);
+    } else {
+      assert(Src.isReg());
+      unsigned Reg = Src.getReg();
+      int Offset = Dst.getOffset();
+      MCCFIInstruction Inst =
+        MCCFIInstruction::createCFIOffset(Label, Reg, Offset);
+      Instructions.push_back(Inst);
+    }
   }
 
   EmitCFIInstructions(streamer, Instructions, NULL);
diff --git a/lib/MC/MCStreamer.cpp b/lib/MC/MCStreamer.cpp
index 02e1028..b8e768c 100644
--- a/lib/MC/MCStreamer.cpp
+++ b/lib/MC/MCStreamer.cpp
@@ -239,9 +239,8 @@ void MCStreamer::EmitCFIDefCfa(int64_t Register, int64_t Offset) {
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
   MCSymbol *Label = getContext().CreateTempSymbol();
   EmitLabel(Label);
-  MachineLocation Dest(MachineLocation::VirtualFP);
-  MachineLocation Source(Register, -Offset);
-  MCCFIInstruction Instruction(Label, Dest, Source);
+  MCCFIInstruction Instruction =
+    MCCFIInstruction::createDefCfa(Label, Register, Offset);
   CurFrame->Instructions.push_back(Instruction);
 }
 
@@ -250,9 +249,8 @@ void MCStreamer::EmitCFIDefCfaOffset(int64_t Offset) {
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
   MCSymbol *Label = getContext().CreateTempSymbol();
   EmitLabel(Label);
-  MachineLocation Dest(MachineLocation::VirtualFP);
-  MachineLocation Source(MachineLocation::VirtualFP, -Offset);
-  MCCFIInstruction Instruction(Label, Dest, Source);
+  MCCFIInstruction Instruction =
+    MCCFIInstruction::createDefCfaOffset(Label, Offset);
   CurFrame->Instructions.push_back(Instruction);
 }
 
@@ -261,9 +259,8 @@ void MCStreamer::EmitCFIAdjustCfaOffset(int64_t Adjustment) {
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
   MCSymbol *Label = getContext().CreateTempSymbol();
   EmitLabel(Label);
-  MachineLocation Dest(MachineLocation::VirtualFP);
-  MachineLocation Source(MachineLocation::VirtualFP, Adjustment);
-  MCCFIInstruction Instruction(MCCFIInstruction::RelMove, Label, Dest, Source);
+  MCCFIInstruction Instruction =
+    MCCFIInstruction::createAdjustCfaOffset(Label, Adjustment);
   CurFrame->Instructions.push_back(Instruction);
 }
 
@@ -272,9 +269,8 @@ void MCStreamer::EmitCFIDefCfaRegister(int64_t Register) {
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
   MCSymbol *Label = getContext().CreateTempSymbol();
   EmitLabel(Label);
-  MachineLocation Dest(Register);
-  MachineLocation Source(MachineLocation::VirtualFP);
-  MCCFIInstruction Instruction(Label, Dest, Source);
+  MCCFIInstruction Instruction =
+    MCCFIInstruction::createDefCfaRegister(Label, Register);
   CurFrame->Instructions.push_back(Instruction);
 }
 
@@ -283,9 +279,8 @@ void MCStreamer::EmitCFIOffset(int64_t Register, int64_t Offset) {
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
   MCSymbol *Label = getContext().CreateTempSymbol();
   EmitLabel(Label);
-  MachineLocation Dest(Register, Offset);
-  MachineLocation Source(Register, Offset);
-  MCCFIInstruction Instruction(Label, Dest, Source);
+  MCCFIInstruction Instruction =
+    MCCFIInstruction::createCFIOffset(Label, Register, Offset);
   CurFrame->Instructions.push_back(Instruction);
 }
 
@@ -294,9 +289,8 @@ void MCStreamer::EmitCFIRelOffset(int64_t Register, int64_t Offset) {
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
   MCSymbol *Label = getContext().CreateTempSymbol();
   EmitLabel(Label);
-  MachineLocation Dest(Register, Offset);
-  MachineLocation Source(Register, Offset);
-  MCCFIInstruction Instruction(MCCFIInstruction::RelMove, Label, Dest, Source);
+  MCCFIInstruction Instruction =
+    MCCFIInstruction::createRelOffset(Label, Register, Offset);
   CurFrame->Instructions.push_back(Instruction);
 }
 
@@ -320,7 +314,7 @@ void MCStreamer::EmitCFIRememberState() {
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
   MCSymbol *Label = getContext().CreateTempSymbol();
   EmitLabel(Label);
-  MCCFIInstruction Instruction(MCCFIInstruction::RememberState, Label);
+  MCCFIInstruction Instruction = MCCFIInstruction::createRememberState(Label);
   CurFrame->Instructions.push_back(Instruction);
 }
 
@@ -330,7 +324,7 @@ void MCStreamer::EmitCFIRestoreState() {
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
   MCSymbol *Label = getContext().CreateTempSymbol();
   EmitLabel(Label);
-  MCCFIInstruction Instruction(MCCFIInstruction::RestoreState, Label);
+  MCCFIInstruction Instruction = MCCFIInstruction::createRestoreState(Label);
   CurFrame->Instructions.push_back(Instruction);
 }
 
@@ -339,7 +333,8 @@ void MCStreamer::EmitCFISameValue(int64_t Register) {
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
   MCSymbol *Label = getContext().CreateTempSymbol();
   EmitLabel(Label);
-  MCCFIInstruction Instruction(MCCFIInstruction::SameValue, Label, Register);
+  MCCFIInstruction Instruction =
+    MCCFIInstruction::createSameValue(Label, Register);
   CurFrame->Instructions.push_back(Instruction);
 }
 
@@ -348,7 +343,8 @@ void MCStreamer::EmitCFIRestore(int64_t Register) {
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
   MCSymbol *Label = getContext().CreateTempSymbol();
   EmitLabel(Label);
-  MCCFIInstruction Instruction(MCCFIInstruction::Restore, Label, Register);
+  MCCFIInstruction Instruction =
+    MCCFIInstruction::createRestore(Label, Register);
   CurFrame->Instructions.push_back(Instruction);
 }
 
@@ -357,7 +353,7 @@ void MCStreamer::EmitCFIEscape(StringRef Values) {
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
   MCSymbol *Label = getContext().CreateTempSymbol();
   EmitLabel(Label);
-  MCCFIInstruction Instruction(MCCFIInstruction::Escape, Label, Values);
+  MCCFIInstruction Instruction = MCCFIInstruction::createEscape(Label, Values);
   CurFrame->Instructions.push_back(Instruction);
 }
 
@@ -372,7 +368,8 @@ void MCStreamer::EmitCFIUndefined(int64_t Register) {
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
   MCSymbol *Label = getContext().CreateTempSymbol();
   EmitLabel(Label);
-  MCCFIInstruction Instruction(MCCFIInstruction::Undefined, Label, Register);
+  MCCFIInstruction Instruction =
+    MCCFIInstruction::createUndefined(Label, Register);
   CurFrame->Instructions.push_back(Instruction);
 }