From 923f3dac014c876e91bf1d797fa3e7e3d8a5e10b Mon Sep 17 00:00:00 2001
From: Johnny Chen <johnny.chen@apple.com>
Date: Sat, 26 Mar 2011 01:32:48 +0000
Subject: [PATCH] Fixed the t2PLD and friends disassembly and add two test
 cases.

llvm-svn: 128322
---
 .../ARM/Disassembler/ARMDisassembler.cpp      | 37 ++++++++++++++++++-
 .../ARM/Disassembler/ThumbDisassemblerCore.h  | 12 ++----
 llvm/test/MC/Disassembler/ARM/thumb-tests.txt |  6 +++
 3 files changed, 45 insertions(+), 10 deletions(-)

diff --git a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index 42c267b45ee0..74f8b53b48cf 100644
--- a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -284,6 +284,24 @@ static unsigned T2Morph2LoadLiteral(unsigned Opcode) {
   }
 }
 
+// Helper function for special case handling of PLD (literal) and friends.
+// See A8.6.117 T1 & T2 and friends for why we morphed the opcode
+// before returning it.
+static unsigned T2Morph2PLDLiteral(unsigned Opcode) {
+  switch (Opcode) {
+  default:
+    return Opcode; // Return unmorphed opcode.
+
+  case ARM::t2PLDi8:   case ARM::t2PLDs:
+  case ARM::t2PLDWi12: case ARM::t2PLDWi8:
+  case ARM::t2PLDWs:
+    return ARM::t2PLDi12;
+
+  case ARM::t2PLIi8:   case ARM::t2PLIs:
+    return ARM::t2PLIi12;
+  }
+}
+
 /// decodeThumbSideEffect is a decorator function which can potentially twiddle
 /// the instruction or morph the returned opcode under Thumb2.
 ///
@@ -334,12 +352,27 @@ static unsigned decodeThumbSideEffect(bool IsThumb2, unsigned &insn) {
     }
     // --------- Transform End Marker ---------
 
+    unsigned unmorphed = decodeThumbInstruction(insn);
+
     // See, for example, A6.3.7 Load word: Table A6-18 Load word.
     // See A8.6.57 T3, T4 & A8.6.60 T2 and friends for why we morphed the opcode
     // before returning it to our caller.
     if (op1 == 3 && slice(op2, 6, 5) == 0 && slice(op2, 0, 0) == 1
-        && slice(insn, 19, 16) == 15)
-      return T2Morph2LoadLiteral(decodeThumbInstruction(insn));
+        && slice(insn, 19, 16) == 15) {
+      unsigned morphed = T2Morph2LoadLiteral(unmorphed);
+      if (morphed != unmorphed)
+        return morphed;
+    }
+
+    // See, for example, A8.6.117 PLD,PLDW (immediate) T1 & T2, and friends for
+    // why we morphed the opcode before returning it to our caller.
+    if (slice(insn, 31, 25) == 0x7C && slice(insn, 15, 12) == 0xF
+        && slice(insn, 22, 22) == 0 && slice(insn, 20, 20) == 1
+        && slice(insn, 19, 16) == 15) {
+      unsigned morphed = T2Morph2PLDLiteral(unmorphed);
+      if (morphed != unmorphed)
+        return morphed;
+    }
 
     // One last check for NEON/VFP instructions.
     if ((op1 == 1 || op1 == 3) && slice(op2, 6, 6) == 1)
diff --git a/llvm/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h b/llvm/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
index d08e98f511e8..ac6eb67579d0 100644
--- a/llvm/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
+++ b/llvm/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
@@ -1786,7 +1786,7 @@ static bool DisassembleThumb2PreLoad(MCInst &MI, unsigned Opcode, uint32_t insn,
                                                      decodeRn(insn))));
   ++OpIdx;
 
-  if (OpInfo[OpIdx].RegClass == ARM::GPRRegClassID) {
+  if (OpInfo[OpIdx].RegClass == ARM::rGPRRegClassID) {
     MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
                                                        decodeRm(insn))));
   } else {
@@ -1794,15 +1794,11 @@ static bool DisassembleThumb2PreLoad(MCInst &MI, unsigned Opcode, uint32_t insn,
            && !OpInfo[OpIdx].isOptionalDef()
            && "Pure imm operand expected");
     int Offset = 0;
-    if (slice(insn, 19, 16) == 0xFF) {
-      bool Negative = slice(insn, 23, 23) == 0;
-      unsigned Imm12 = getImm12(insn);
-      Offset = Negative ? -1 - Imm12 : 1 * Imm12;
-    } else if (Opcode == ARM::t2PLDi8 || Opcode == ARM::t2PLDWi8 ||
-               Opcode == ARM::t2PLIi8) {
+    if (Opcode == ARM::t2PLDi8 || Opcode == ARM::t2PLDWi8 ||
+        Opcode == ARM::t2PLIi8) {
       // A8.6.117 Encoding T2: add = FALSE
       unsigned Imm8 = getImm8(insn);
-      Offset = -1 - Imm8;
+      Offset = -1 * Imm8;
     } else // The i12 forms.  See, for example, A8.6.117 Encoding T1.
       Offset = decodeImm12(insn);
     MI.addOperand(MCOperand::CreateImm(Offset));
diff --git a/llvm/test/MC/Disassembler/ARM/thumb-tests.txt b/llvm/test/MC/Disassembler/ARM/thumb-tests.txt
index b167ad1153b7..2ab75405e0cb 100644
--- a/llvm/test/MC/Disassembler/ARM/thumb-tests.txt
+++ b/llvm/test/MC/Disassembler/ARM/thumb-tests.txt
@@ -190,3 +190,9 @@
 
 # CHECK:	umull	r1, r2, r3, r4
 0xa3 0xfb 0x04 0x12
+
+# CHECK:	pld	[r5, r0, lsl #1]
+0x15 0xf8 0x10 0xf0
+
+# CHECK:	pld	[pc, #-16]
+0x1f 0xf8 0x10 0xf0