Pull in r222587 from upstream llvm trunk (by Jörg Sonnenberger):

  Fix transformation of add with pc argument to adr for non-immediate
  arguments.

This fixes an "Unimplemented" error when assembling certain ARM add
instructions with pc-relative arguments.

Reported by:	sbruno
PR:		196412, 196423

Introduced here: http://svnweb.freebsd.org/changeset/base/276537

Index: lib/Target/ARM/AsmParser/ARMAsmParser.cpp
===================================================================
--- lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -314,7 +314,7 @@ class ARMAsmParser : public MCTargetAsmParser {
   void cvtThumbBranches(MCInst &Inst, const OperandVector &);
 
   bool validateInstruction(MCInst &Inst, const OperandVector &Ops);
-  bool processInstruction(MCInst &Inst, const OperandVector &Ops);
+  bool processInstruction(MCInst &Inst, const OperandVector &Ops, MCStreamer &Out);
   bool shouldOmitCCOutOperand(StringRef Mnemonic, OperandVector &Operands);
   bool shouldOmitPredicateOperand(StringRef Mnemonic, OperandVector &Operands);
 
@@ -6175,7 +6175,8 @@ static unsigned getRealVLDOpcode(unsigned Opc, uns
 }
 
 bool ARMAsmParser::processInstruction(MCInst &Inst,
-                                      const OperandVector &Operands) {
+                                      const OperandVector &Operands,
+                                      MCStreamer &Out) {
   switch (Inst.getOpcode()) {
   // Alias for alternate form of 'ldr{,b}t Rt, [Rn], #imm' instruction.
   case ARM::LDRT_POST:
@@ -6216,12 +6217,31 @@ bool ARMAsmParser::processInstruction(MCInst &Inst
   // Alias for alternate form of 'ADR Rd, #imm' instruction.
   case ARM::ADDri: {
     if (Inst.getOperand(1).getReg() != ARM::PC ||
-        Inst.getOperand(5).getReg() != 0)
+        Inst.getOperand(5).getReg() != 0 ||
+        !(Inst.getOperand(2).isExpr() || Inst.getOperand(2).isImm()))
       return false;
     MCInst TmpInst;
     TmpInst.setOpcode(ARM::ADR);
     TmpInst.addOperand(Inst.getOperand(0));
-    TmpInst.addOperand(Inst.getOperand(2));
+    if (Inst.getOperand(2).isImm()) {
+      TmpInst.addOperand(Inst.getOperand(2));
+    } else {
+      // Turn PC-relative expression into absolute expression.
+      // Reading PC provides the start of the current instruction + 8 and
+      // the transform to adr is biased by that.
+      MCSymbol *Dot = getContext().CreateTempSymbol();
+      Out.EmitLabel(Dot);
+      const MCExpr *OpExpr = Inst.getOperand(2).getExpr();
+      const MCExpr *InstPC = MCSymbolRefExpr::Create(Dot,
+                                                     MCSymbolRefExpr::VK_None,
+                                                     getContext());
+      const MCExpr *Const8 = MCConstantExpr::Create(8, getContext());
+      const MCExpr *ReadPC = MCBinaryExpr::CreateAdd(InstPC, Const8,
+                                                     getContext());
+      const MCExpr *FixupAddr = MCBinaryExpr::CreateAdd(ReadPC, OpExpr,
+                                                        getContext());
+      TmpInst.addOperand(MCOperand::CreateExpr(FixupAddr));
+    }
     TmpInst.addOperand(Inst.getOperand(3));
     TmpInst.addOperand(Inst.getOperand(4));
     Inst = TmpInst;
@@ -8061,7 +8081,7 @@ bool ARMAsmParser::MatchAndEmitInstruction(SMLoc I
       // encoding is selected. Loop on it while changes happen so the
       // individual transformations can chain off each other. E.g.,
       // tPOP(r8)->t2LDMIA_UPD(sp,r8)->t2STR_POST(sp,r8)
-      while (processInstruction(Inst, Operands))
+      while (processInstruction(Inst, Operands, Out))
         ;
 
       // Only after the instruction is fully processed, we can validate it
Index: test/MC/ARM/basic-arm-instructions.s
===================================================================
--- test/MC/ARM/basic-arm-instructions.s
+++ test/MC/ARM/basic-arm-instructions.s
@@ -191,8 +191,10 @@ Lforward:
 
 	add r0, #-4
 	add r4, r5, #-21
-        add r0, pc, #0xc0000000
+	add r0, pc, #0xc0000000
 
+	add r0, pc, #(Lback - .)
+
 @ CHECK: add	r4, r5, #61440          @ encoding: [0x0f,0x4a,0x85,0xe2]
 @ CHECK: add	r4, r5, r6              @ encoding: [0x06,0x40,0x85,0xe0]
 @ CHECK: add	r4, r5, r6, lsl #5      @ encoding: [0x86,0x42,0x85,0xe0]
@@ -222,7 +224,11 @@ Lforward:
 
 @ CHECK: sub	r0, r0, #4              @ encoding: [0x04,0x00,0x40,0xe2]
 @ CHECK: sub	r4, r5, #21             @ encoding: [0x15,0x40,0x45,0xe2]
-@ CHECK: adr    r0, #-1073741824        @ encoding: [0x03,0x01,0x8f,0xe2]
+@ CHECK: adr	r0, #-1073741824        @ encoding: [0x03,0x01,0x8f,0xe2]
+@ CHECK:        Ltmp0:
+@ CHECK-NEXT:   Ltmp1:
+@ CHECK-NEXT:   adr	r0, (Ltmp1+8)+(Lback-Ltmp0) @ encoding: [A,A,0x0f'A',0xe2'A']
+@ CHECK-NEXT:                           @   fixup A - offset: 0, value: (Ltmp1+8)+(Lback-Ltmp0), kind: fixup_arm_adr_pcrel_12
 
     @ Test right shift by 32, which is encoded as 0
     add r3, r1, r2, lsr #32