AArch64: use default asm operand printing when modifier inapplicable

If an inline assembly operand has multiple constraints (e.g. "Ir" for immediate
or register) and an operand modifier (E.g. "w" for "print register as wN") then
we need to decide behaviour when the modifier doesn't apply to the constraint.

Previousely produced some combination of an assertion failure and a fatal
error. GCC's behaviour appears to be to ignore the modifier and print the
operand in the default way. This patch should implement that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194024 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 59 insertions, 47 deletions

diff --git a/lib/Target/AArch64/AArch64AsmPrinter.cpp b/lib/Target/AArch64/AArch64AsmPrinter.cpp
index f877fa7e4b..eb4a2abaf8 100644
--- a/lib/Target/AArch64/AArch64AsmPrinter.cpp
+++ b/lib/Target/AArch64/AArch64AsmPrinter.cpp
@@ -82,7 +82,7 @@ bool AArch64AsmPrinter::printSymbolicAddress(const MachineOperand &MO,
   StringRef Modifier;
   switch (MO.getType()) {
   default:
-    llvm_unreachable("Unexpected operand for symbolic address constraint");
+    return true;
   case MachineOperand::MO_GlobalAddress:
     Name = getSymbol(MO.getGlobal())->getName();
 
@@ -146,57 +146,33 @@ bool AArch64AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
                                         unsigned AsmVariant,
                                         const char *ExtraCode, raw_ostream &O) {
   const TargetRegisterInfo *TRI = MF->getTarget().getRegisterInfo();
-  if (!ExtraCode || !ExtraCode[0]) {
-    // There's actually no operand modifier, which leads to a slightly eclectic
-    // set of behaviour which we have to handle here.
-    const MachineOperand &MO = MI->getOperand(OpNum);
-    switch (MO.getType()) {
-    default:
-      llvm_unreachable("Unexpected operand for inline assembly");
-    case MachineOperand::MO_Register:
-      // GCC prints the unmodified operand of a 'w' constraint as the vector
-      // register. Technically, we could allocate the argument as a VPR128, but
-      // that leads to extremely dodgy copies being generated to get the data
-      // there.
-      if (printModifiedFPRAsmOperand(MO, TRI, 'v', O))
-        O << AArch64InstPrinter::getRegisterName(MO.getReg());
-      break;
-    case MachineOperand::MO_Immediate:
-      O << '#' << MO.getImm();
-      break;
-    case MachineOperand::MO_FPImmediate:
-      assert(MO.getFPImm()->isExactlyValue(0.0) && "Only FP 0.0 expected");
-      O << "#0.0";
-      break;
-    case MachineOperand::MO_BlockAddress:
-    case MachineOperand::MO_ConstantPoolIndex:
-    case MachineOperand::MO_GlobalAddress:
-    case MachineOperand::MO_ExternalSymbol:
-      return printSymbolicAddress(MO, false, "", O);
-    }
-    return false;
-  }
 
-  // We have a real modifier to handle.
+  if (!ExtraCode)
+    ExtraCode = "";
+
   switch(ExtraCode[0]) {
   default:
-    // See if this is a generic operand
-    return AsmPrinter::PrintAsmOperand(MI, OpNum, AsmVariant, ExtraCode, O);
+    break;
   case 'c': // Don't print "#" before an immediate operand.
-    if (!MI->getOperand(OpNum).isImm())
-      return true;
-    O << MI->getOperand(OpNum).getImm();
-    return false;
+    if (MI->getOperand(OpNum).isImm()) {
+      O << MI->getOperand(OpNum).getImm();
+      return false;
+    }
+    break;
   case 'w':
     // Output 32-bit general register operand, constant zero as wzr, or stack
     // pointer as wsp. Ignored when used with other operand types.
-    return printModifiedGPRAsmOperand(MI->getOperand(OpNum), TRI,
-                                      AArch64::GPR32RegClass, O);
+    if (!printModifiedGPRAsmOperand(MI->getOperand(OpNum), TRI,
+                                    AArch64::GPR32RegClass, O))
+      return false;
+    break;
   case 'x':
     // Output 64-bit general register operand, constant zero as xzr, or stack
     // pointer as sp. Ignored when used with other operand types.
-    return printModifiedGPRAsmOperand(MI->getOperand(OpNum), TRI,
-                                      AArch64::GPR64RegClass, O);
+    if (!printModifiedGPRAsmOperand(MI->getOperand(OpNum), TRI,
+                                    AArch64::GPR64RegClass, O))
+      return false;
+    break;
   case 'H':
     // Output higher numbered of a 64-bit general register pair
   case 'Q':
@@ -216,25 +192,61 @@ bool AArch64AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
   case 's':
   case 'd':
   case 'q':
-    return printModifiedFPRAsmOperand(MI->getOperand(OpNum), TRI,
-                                      ExtraCode[0], O);
+    if (!printModifiedFPRAsmOperand(MI->getOperand(OpNum), TRI,
+                                    ExtraCode[0], O))
+      return false;
+    break;
   case 'A':
     // Output symbolic address with appropriate relocation modifier (also
     // suitable for ADRP).
-    return printSymbolicAddress(MI->getOperand(OpNum), false, "", O);
+    if (!printSymbolicAddress(MI->getOperand(OpNum), false, "", O))
+      return false;
+    break;
   case 'L':
     // Output bits 11:0 of symbolic address with appropriate :lo12: relocation
     // modifier.
-    return printSymbolicAddress(MI->getOperand(OpNum), true, "lo12", O);
+    if (!printSymbolicAddress(MI->getOperand(OpNum), true, "lo12", O))
+      return false;
+    break;
   case 'G':
     // Output bits 23:12 of symbolic address with appropriate :hi12: relocation
     // modifier (currently only for TLS local exec).
-    return printSymbolicAddress(MI->getOperand(OpNum), true, "hi12", O);
+    if (!printSymbolicAddress(MI->getOperand(OpNum), true, "hi12", O))
+      return false;
+    break;
   case 'a':
     return PrintAsmMemoryOperand(MI, OpNum, AsmVariant, ExtraCode, O);
   }
 
+  // There's actually no operand modifier, which leads to a slightly eclectic
+  // set of behaviour which we have to handle here.
+  const MachineOperand &MO = MI->getOperand(OpNum);
+  switch (MO.getType()) {
+  default:
+    llvm_unreachable("Unexpected operand for inline assembly");
+  case MachineOperand::MO_Register:
+    // GCC prints the unmodified operand of a 'w' constraint as the vector
+    // register. Technically, we could allocate the argument as a VPR128, but
+    // that leads to extremely dodgy copies being generated to get the data
+    // there.
+    if (printModifiedFPRAsmOperand(MO, TRI, 'v', O))
+      O << AArch64InstPrinter::getRegisterName(MO.getReg());
+    break;
+  case MachineOperand::MO_Immediate:
+    O << '#' << MO.getImm();
+    break;
+  case MachineOperand::MO_FPImmediate:
+    assert(MO.getFPImm()->isExactlyValue(0.0) && "Only FP 0.0 expected");
+    O << "#0.0";
+    break;
+  case MachineOperand::MO_BlockAddress:
+  case MachineOperand::MO_ConstantPoolIndex:
+  case MachineOperand::MO_GlobalAddress:
+  case MachineOperand::MO_ExternalSymbol:
+    return printSymbolicAddress(MO, false, "", O);
+  }
 
+  return false;
 }
 
 bool AArch64AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,