Reapply an improved version of r180816/180817.

Change the informal convention of DBG_VALUE machine instructions so that
we can express a register-indirect address with an offset of 0.
The old convention was that a DBG_VALUE is a register-indirect value if
the offset (operand 1) is nonzero. The new convention is that a DBG_VALUE
is register-indirect if the first operand is a register and the second
operand is an immediate. For plain register values the combination reg,
reg is used. MachineInstrBuilder::BuildMI knows how to build the new
DBG_VALUES.

rdar://problem/13658587

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185966 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 45 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/MachineInstrBuilder.h b/include/llvm/CodeGen/MachineInstrBuilder.h
index 92c8da9..df01371 100644
--- a/include/llvm/CodeGen/MachineInstrBuilder.h
+++ b/include/llvm/CodeGen/MachineInstrBuilder.h
@@ -335,6 +335,51 @@ inline MachineInstrBuilder BuildMI(MachineBasicBlock *BB,
   return BuildMI(*BB, BB->end(), DL, MCID, DestReg);
 }
 
+/// BuildMI - This version of the builder builds a DBG_VALUE intrinsic
+/// for either a value in a register or a register-indirect+offset
+/// address.  The convention is that a DBG_VALUE is indirect iff the
+/// second operand is an immediate.
+///
+inline MachineInstrBuilder BuildMI(MachineFunction &MF,
+                                   DebugLoc DL,
+                                   const MCInstrDesc &MCID,
+                                   bool IsIndirect,
+                                   unsigned Reg,
+                                   unsigned Offset,
+                                   const MDNode *MD) {
+  if (IsIndirect)
+    return BuildMI(MF, DL, MCID)
+      .addReg(Reg, RegState::Debug)
+      .addImm(Offset)
+      .addMetadata(MD);
+  else {
+    assert(Offset == 0 && "A direct address cannot have an offset.");
+    return BuildMI(MF, DL, MCID)
+      .addReg(Reg, RegState::Debug)
+      .addReg(0U, RegState::Debug)
+      .addMetadata(MD);
+  }
+}
+
+/// BuildMI - This version of the builder builds a DBG_VALUE intrinsic
+/// for either a value in a register or a register-indirect+offset
+/// address and inserts it at position I.
+///
+inline MachineInstrBuilder BuildMI(MachineBasicBlock &BB,
+                                   MachineBasicBlock::iterator I,
+                                   DebugLoc DL,
+                                   const MCInstrDesc &MCID,
+                                   bool IsIndirect,
+                                   unsigned Reg,
+                                   unsigned Offset,
+                                   const MDNode *MD) {
+  MachineFunction &MF = *BB.getParent();
+  MachineInstr *MI = BuildMI(MF, DL, MCID, IsIndirect, Reg, Offset, MD);
+  BB.insert(I, MI);
+  return MachineInstrBuilder(MF, MI);
+}
+
+
 inline unsigned getDefRegState(bool B) {
   return B ? RegState::Define : 0;
 }