[ARM] Add support for mrrc/mrrc2 intrinsics.

Reapplying patch as it was reverted when it was first
committed because of an assertion failure when the
mrrc2 intrinsic was called in ARM mode. The failure
was happening because the instruction was being built
in ARMISelDAGToDAG.cpp and the tablegen description for
mrrc2 instruction doesn't allow you to use a predicate.

The ARM architecture manuals do say that mrrc2 in ARM
mode can be predicated with AL in assembly but this has
no effect on the encoding of the instruction as the top
4 bits will always be 1111 not 1110 which is the encoding
for the condition AL.

Differential Revision: http://reviews.llvm.org/D21408

llvm-svn: 272982

1 files changed, 26 insertions, 8 deletions

diff --git a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index ad1e03a..3196a57 100644
--- a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -395,8 +395,8 @@ static DecodeStatus DecodeT2ShifterImmOperand(MCInst &Inst, unsigned Val,
 
 static DecodeStatus DecodeLDR(MCInst &Inst, unsigned Val,
                                 uint64_t Address, const void *Decoder);
-static DecodeStatus DecodeMRRC2(llvm::MCInst &Inst, unsigned Val,
-                                uint64_t Address, const void *Decoder);
+static DecodeStatus DecoderForMRRC2AndMCRR2(llvm::MCInst &Inst, unsigned Val,
+                                            uint64_t Address, const void *Decoder);
 #include "ARMGenDisassemblerTables.inc"
 
 static MCDisassembler *createARMDisassembler(const Target &T,
@@ -5265,8 +5265,8 @@ static DecodeStatus DecodeLDR(MCInst &Inst, unsigned Val,
   return S;
 }
 
-static DecodeStatus DecodeMRRC2(llvm::MCInst &Inst, unsigned Val,
-                                uint64_t Address, const void *Decoder) {
+static DecodeStatus DecoderForMRRC2AndMCRR2(llvm::MCInst &Inst, unsigned Val,
+                                            uint64_t Address, const void *Decoder) {
 
   DecodeStatus S = MCDisassembler::Success;
 
@@ -5282,12 +5282,30 @@ static DecodeStatus DecodeMRRC2(llvm::MCInst &Inst, unsigned Val,
   if (Rt == Rt2)
     S = MCDisassembler::SoftFail;
 
+  // We have to check if the instruction is MRRC2
+  // or MCRR2 when constructing the operands for
+  // Inst. Reason is because MRRC2 stores to two
+  // registers so it's tablegen desc has has two
+  // outputs whereas MCRR doesn't store to any
+  // registers so all of it's operands are listed
+  // as inputs, therefore the operand order for
+  // MRRC2 needs to be [Rt, Rt2, cop, opc1, CRm]
+  // and MCRR2 operand order is [cop, opc1, Rt, Rt2, CRm]
+
+  if (Inst.getOpcode() == ARM::MRRC2) {
+    if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
+      return MCDisassembler::Fail;
+    if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
+      return MCDisassembler::Fail;
+  }
   Inst.addOperand(MCOperand::createImm(cop));
   Inst.addOperand(MCOperand::createImm(opc1));
-  if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
-    return MCDisassembler::Fail;
-  if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
-    return MCDisassembler::Fail;
+  if (Inst.getOpcode() == ARM::MCRR2) {
+    if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
+      return MCDisassembler::Fail;
+    if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
+      return MCDisassembler::Fail;
+  }
   Inst.addOperand(MCOperand::createImm(CRm));
 
   return S;