From f1aa47dc1aed018e2f70ffe7d32dba51e2ac45fe Mon Sep 17 00:00:00 2001
From: Jim Grosbach <grosbach@apple.com>
Date: Mon, 29 Nov 2010 19:32:47 +0000
Subject: [PATCH] ARM Pseudo-ize tBR_JTr.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120310 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMAsmPrinter.cpp            | 20 +++++++-------------
 lib/Target/ARM/ARMInstrFormats.td           | 10 +++++++---
 lib/Target/ARM/ARMInstrInfo.td              |  3 ---
 lib/Target/ARM/ARMInstrThumb.td             | 13 +++++--------
 lib/Target/ARM/InstPrinter/ARMInstPrinter.h |  1 -
 5 files changed, 19 insertions(+), 28 deletions(-)

diff --git a/lib/Target/ARM/ARMAsmPrinter.cpp b/lib/Target/ARM/ARMAsmPrinter.cpp
index 84ddab99aaa..da1c087c7fe 100644
--- a/lib/Target/ARM/ARMAsmPrinter.cpp
+++ b/lib/Target/ARM/ARMAsmPrinter.cpp
@@ -936,23 +936,13 @@ void ARMAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     EmitJump2Table(MI);
     return;
   }
-  case ARM::tBR_JTr: {
-    // Lower and emit the instruction itself, then the jump table following it.
-    MCInst TmpInst;
-    // FIXME: The branch instruction is really a pseudo. We should xform it
-    // explicitly.
-    LowerARMMachineInstrToMCInst(MI, TmpInst, *this);
-    OutStreamer.EmitInstruction(TmpInst);
-
-    // Output the data for the jump table itself
-    EmitJumpTable(MI);
-    return;
-  }
+  case ARM::tBR_JTr:
   case ARM::BR_JTr: {
     // Lower and emit the instruction itself, then the jump table following it.
     // mov pc, target
     MCInst TmpInst;
-    TmpInst.setOpcode(ARM::MOVr);
+    unsigned Opc = MI->getOpcode() == ARM::BR_JTr ? ARM::MOVr : ARM::tMOVr;
+    TmpInst.setOpcode(Opc);
     TmpInst.addOperand(MCOperand::CreateReg(ARM::PC));
     TmpInst.addOperand(MCOperand::CreateReg(MI->getOperand(0).getReg()));
     // Add predicate operands.
@@ -960,6 +950,10 @@ void ARMAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     TmpInst.addOperand(MCOperand::CreateReg(0));
     OutStreamer.EmitInstruction(TmpInst);
 
+    // Make sure the Thumb jump table is 4-byte aligned.
+    if (Opc == ARM::tMOVr)
+      EmitAlignment(2);
+
     // Output the data for the jump table itself
     EmitJumpTable(MI);
     return;
diff --git a/lib/Target/ARM/ARMInstrFormats.td b/lib/Target/ARM/ARMInstrFormats.td
index a5f89d6e49f..04c9b0e52af 100644
--- a/lib/Target/ARM/ARMInstrFormats.td
+++ b/lib/Target/ARM/ARMInstrFormats.td
@@ -255,6 +255,13 @@ class ARMPseudoInst<dag oops, dag iops, InstrItinClass itin,
   list<Predicate> Predicates = [IsARM];
 }
 
+// PseudoInst that's Thumb-mode only.
+class tPseudoInst<dag oops, dag iops, SizeFlagVal sz, InstrItinClass itin,
+                    list<dag> pattern>
+  : PseudoInst<oops, iops, itin, pattern> {
+  let SZ = sz;
+  list<Predicate> Predicates = [IsThumb];
+}
 
 // Almost all ARM instructions are predicable.
 class I<dag oops, dag iops, AddrMode am, SizeFlagVal sz,
@@ -816,9 +823,6 @@ class T1I<dag oops, dag iops, InstrItinClass itin,
 class T1Ix2<dag oops, dag iops, InstrItinClass itin,
             string asm, list<dag> pattern>
   : Thumb1I<oops, iops, AddrModeNone, Size4Bytes, itin, asm, "", pattern>;
-class T1JTI<dag oops, dag iops, InstrItinClass itin,
-            string asm, list<dag> pattern>
-  : Thumb1I<oops, iops, AddrModeNone, SizeSpecial, itin, asm, "", pattern>;
 
 // Two-address instructions
 class T1It<dag oops, dag iops, InstrItinClass itin,
diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index e09170f631a..61ab5496e6e 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -333,9 +333,6 @@ def cpinst_operand : Operand<i32> {
   let PrintMethod = "printCPInstOperand";
 }
 
-def jtblock_operand : Operand<i32> {
-  let PrintMethod = "printJTBlockOperand";
-}
 def jt2block_operand : Operand<i32> {
   let PrintMethod = "printJT2BlockOperand";
 }
diff --git a/lib/Target/ARM/ARMInstrThumb.td b/lib/Target/ARM/ARMInstrThumb.td
index 3af89341196..568cbc6c6c6 100644
--- a/lib/Target/ARM/ARMInstrThumb.td
+++ b/lib/Target/ARM/ARMInstrThumb.td
@@ -439,14 +439,11 @@ let isBranch = 1, isTerminator = 1 in {
   def tBfar : TIx2<0b11110, 0b11, 1, (outs), (ins brtarget:$target), IIC_Br,
                     "bl\t$target",[]>;
 
-  let isCodeGenOnly = 1 in
-  def tBR_JTr : T1JTI<(outs),
-                      (ins tGPR:$target, jtblock_operand:$jt, i32imm:$id),
-                      IIC_Br, "mov\tpc, $target\n\t.align\t2$jt",
-                      [(ARMbrjt tGPR:$target, tjumptable:$jt, imm:$id)]>,
-                Encoding16 {
-    let Inst{15-7} = 0b010001101;
-    let Inst{2-0} = 0b111;
+  def tBR_JTr : tPseudoInst<(outs),
+                      (ins tGPR:$target, i32imm:$jt, i32imm:$id),
+                      Size2Bytes, IIC_Br,
+                      [(ARMbrjt tGPR:$target, tjumptable:$jt, imm:$id)]> {
+    list<Predicate> Predicates = [IsThumb, IsThumb1Only];
   }
   }
 }
diff --git a/lib/Target/ARM/InstPrinter/ARMInstPrinter.h b/lib/Target/ARM/InstPrinter/ARMInstPrinter.h
index e69a0e0d8f7..55605ead067 100644
--- a/lib/Target/ARM/InstPrinter/ARMInstPrinter.h
+++ b/lib/Target/ARM/InstPrinter/ARMInstPrinter.h
@@ -96,7 +96,6 @@ public:
   void printRegisterList(const MCInst *MI, unsigned OpNum, raw_ostream &O);
   // The jump table instructions have custom handling in ARMAsmPrinter
   // to output the jump table. Nothing further is necessary here.
-  void printJTBlockOperand(const MCInst *MI, unsigned OpNum, raw_ostream &O) {}
   void printJT2BlockOperand(const MCInst *MI, unsigned OpNum, raw_ostream &O) {}
   void printTBAddrMode(const MCInst *MI, unsigned OpNum, raw_ostream &O);
   void printNoHashImmediate(const MCInst *MI, unsigned OpNum, raw_ostream &O);