Emit diagnostic if an inline asm constraint requires an immediate

Summary:
An inline asm call can result in an immediate after inlining. Therefore emit a
diagnostic here if constraint requires an immediate but one isn't supplied.

Reviewers: joerg, mgorny, efriedma, rsmith

Reviewed By: joerg

Subscribers: asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, s.egerton, MaskRay, jyknight, dylanmckay, javed.absar, fedor.sergeev, jrtc27, Jim, krytarowski, eraman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60942

llvm-svn: 367750
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 0b292b2..90494f2 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -8049,6 +8049,14 @@
     // Compute the constraint code and ConstraintType to use.
     TLI.ComputeConstraintToUse(T, SDValue());
 
+    if (T.ConstraintType == TargetLowering::C_Immediate &&
+        OpInfo.CallOperand && !isa<ConstantSDNode>(OpInfo.CallOperand))
+      // We've delayed emitting a diagnostic like the "n" constraint because
+      // inlining could cause an integer showing up.
+      return emitInlineAsmError(
+          CS, "constraint '" + Twine(T.ConstraintCode) + "' expects an "
+                  "integer constant expression");
+
     ExtraInfo.update(T);
   }
 
@@ -8133,7 +8141,8 @@
     switch (OpInfo.Type) {
     case InlineAsm::isOutput:
       if (OpInfo.ConstraintType == TargetLowering::C_Memory ||
-          (OpInfo.ConstraintType == TargetLowering::C_Other &&
+          ((OpInfo.ConstraintType == TargetLowering::C_Immediate ||
+            OpInfo.ConstraintType == TargetLowering::C_Other) &&
            OpInfo.isIndirect)) {
         unsigned ConstraintID =
             TLI.getInlineAsmMemConstraint(OpInfo.ConstraintCode);
@@ -8147,13 +8156,14 @@
                                                         MVT::i32));
         AsmNodeOperands.push_back(OpInfo.CallOperand);
         break;
-      } else if ((OpInfo.ConstraintType == TargetLowering::C_Other &&
+      } else if (((OpInfo.ConstraintType == TargetLowering::C_Immediate ||
+                   OpInfo.ConstraintType == TargetLowering::C_Other) &&
                   !OpInfo.isIndirect) ||
                  OpInfo.ConstraintType == TargetLowering::C_Register ||
                  OpInfo.ConstraintType == TargetLowering::C_RegisterClass) {
         // Otherwise, this outputs to a register (directly for C_Register /
-        // C_RegisterClass, and a target-defined fashion for C_Other). Find a
-        // register that we can use.
+        // C_RegisterClass, and a target-defined fashion for
+        // C_Immediate/C_Other). Find a register that we can use.
         if (OpInfo.AssignedRegs.Regs.empty()) {
           emitInlineAsmError(
               CS, "couldn't allocate output register for constraint '" +
@@ -8233,15 +8243,24 @@
       }
 
       // Treat indirect 'X' constraint as memory.
-      if (OpInfo.ConstraintType == TargetLowering::C_Other &&
+      if ((OpInfo.ConstraintType == TargetLowering::C_Immediate ||
+           OpInfo.ConstraintType == TargetLowering::C_Other) &&
           OpInfo.isIndirect)
         OpInfo.ConstraintType = TargetLowering::C_Memory;
 
-      if (OpInfo.ConstraintType == TargetLowering::C_Other) {
+      if (OpInfo.ConstraintType == TargetLowering::C_Immediate ||
+          OpInfo.ConstraintType == TargetLowering::C_Other) {
         std::vector<SDValue> Ops;
         TLI.LowerAsmOperandForConstraint(InOperandVal, OpInfo.ConstraintCode,
                                           Ops, DAG);
         if (Ops.empty()) {
+          if (OpInfo.ConstraintType == TargetLowering::C_Immediate)
+            if (isa<ConstantSDNode>(InOperandVal)) {
+              emitInlineAsmError(CS, "value out of range for constraint '" +
+                                 Twine(OpInfo.ConstraintCode) + "'");
+              return;
+            }
+
           emitInlineAsmError(CS, "invalid operand for inline asm constraint '" +
                                      Twine(OpInfo.ConstraintCode) + "'");
           return;
@@ -8278,7 +8297,8 @@
       }
 
       assert((OpInfo.ConstraintType == TargetLowering::C_RegisterClass ||
-              OpInfo.ConstraintType == TargetLowering::C_Register) &&
+              OpInfo.ConstraintType == TargetLowering::C_Register ||
+              OpInfo.ConstraintType == TargetLowering::C_Immediate) &&
              "Unknown constraint type!");
 
       // TODO: Support this.
@@ -8384,6 +8404,7 @@
         Val = OpInfo.AssignedRegs.getCopyFromRegs(
             DAG, FuncInfo, getCurSDLoc(), Chain, &Flag, CS.getInstruction());
         break;
+      case TargetLowering::C_Immediate:
       case TargetLowering::C_Other:
         Val = TLI.LowerAsmOutputForConstraint(Chain, Flag, getCurSDLoc(),
                                               OpInfo, DAG);
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index dd819eb..477a138 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -3873,15 +3873,17 @@
   if (S == 1) {
     switch (Constraint[0]) {
     default: break;
-    case 'r': return C_RegisterClass;
+    case 'r':
+      return C_RegisterClass;
     case 'm': // memory
     case 'o': // offsetable
     case 'V': // not offsetable
       return C_Memory;
-    case 'i': // Simple Integer or Relocatable Constant
     case 'n': // Simple Integer
     case 'E': // Floating Point Constant
     case 'F': // Floating Point Constant
+      return C_Immediate;
+    case 'i': // Simple Integer or Relocatable Constant
     case 's': // Relocatable Constant
     case 'p': // Address.
     case 'X': // Allow ANY value.
@@ -4256,6 +4258,7 @@
 /// Return an integer indicating how general CT is.
 static unsigned getConstraintGenerality(TargetLowering::ConstraintType CT) {
   switch (CT) {
+  case TargetLowering::C_Immediate:
   case TargetLowering::C_Other:
   case TargetLowering::C_Unknown:
     return 0;
@@ -4375,11 +4378,12 @@
     TargetLowering::ConstraintType CType =
       TLI.getConstraintType(OpInfo.Codes[i]);
 
-    // If this is an 'other' constraint, see if the operand is valid for it.
-    // For example, on X86 we might have an 'rI' constraint.  If the operand
-    // is an integer in the range [0..31] we want to use I (saving a load
-    // of a register), otherwise we must use 'r'.
-    if (CType == TargetLowering::C_Other && Op.getNode()) {
+    // If this is an 'other' or 'immediate' constraint, see if the operand is
+    // valid for it. For example, on X86 we might have an 'rI' constraint. If
+    // the operand is an integer in the range [0..31] we want to use I (saving a
+    // load of a register), otherwise we must use 'r'.
+    if ((CType == TargetLowering::C_Other ||
+         CType == TargetLowering::C_Immediate) && Op.getNode()) {
       assert(OpInfo.Codes[i].size() == 1 &&
              "Unhandled multi-letter 'other' constraint");
       std::vector<SDValue> ResultOps;
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 43a7e4f..658cc5b 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -5686,8 +5686,6 @@
     switch (Constraint[0]) {
     default:
       break;
-    case 'z':
-      return C_Other;
     case 'x':
     case 'w':
       return C_RegisterClass;
@@ -5695,6 +5693,16 @@
     // currently handle addresses it is the same as 'r'.
     case 'Q':
       return C_Memory;
+    case 'I':
+    case 'J':
+    case 'K':
+    case 'L':
+    case 'M':
+    case 'N':
+    case 'Y':
+    case 'Z':
+      return C_Immediate;
+    case 'z':
     case 'S': // A symbolic address
       return C_Other;
     }
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index c0232f0..cce57a4 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -14976,7 +14976,8 @@
 /// constraint it is for this target.
 ARMTargetLowering::ConstraintType
 ARMTargetLowering::getConstraintType(StringRef Constraint) const {
-  if (Constraint.size() == 1) {
+  unsigned S = Constraint.size();
+  if (S == 1) {
     switch (Constraint[0]) {
     default:  break;
     case 'l': return C_RegisterClass;
@@ -14984,12 +14985,12 @@
     case 'h': return C_RegisterClass;
     case 'x': return C_RegisterClass;
     case 't': return C_RegisterClass;
-    case 'j': return C_Other; // Constant for movw.
-      // An address with a single base register. Due to the way we
-      // currently handle addresses it is the same as an 'r' memory constraint.
+    case 'j': return C_Immediate; // Constant for movw.
+    // An address with a single base register. Due to the way we
+    // currently handle addresses it is the same as an 'r' memory constraint.
     case 'Q': return C_Memory;
     }
-  } else if (Constraint.size() == 2) {
+  } else if (S == 2) {
     switch (Constraint[0]) {
     default: break;
     case 'T': return C_RegisterClass;
diff --git a/llvm/lib/Target/AVR/AVRISelLowering.cpp b/llvm/lib/Target/AVR/AVRISelLowering.cpp
index b6ba5f2..f159bee 100644
--- a/llvm/lib/Target/AVR/AVRISelLowering.cpp
+++ b/llvm/lib/Target/AVR/AVRISelLowering.cpp
@@ -1689,6 +1689,8 @@
   if (Constraint.size() == 1) {
     // See http://www.nongnu.org/avr-libc/user-manual/inline_asm.html
     switch (Constraint[0]) {
+    default:
+      break;
     case 'a': // Simple upper registers
     case 'b': // Base pointer registers pairs
     case 'd': // Upper register
@@ -1715,9 +1717,7 @@
     case 'O': // Integer constant (Range: 8, 16, 24)
     case 'P': // Integer constant (Range: 1)
     case 'R': // Integer constant (Range: -6 to 5)x
-      return C_Other;
-    default:
-      break;
+      return C_Immediate;
     }
   }
 
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 62c6ba8..dfedbba 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -2407,6 +2407,10 @@
       break;
     case 'f':
       return C_RegisterClass;
+    case 'I':
+    case 'J':
+    case 'K':
+      return C_Immediate;
     }
   }
   return TargetLowering::getConstraintType(Constraint);
diff --git a/llvm/lib/Target/Sparc/SparcISelLowering.cpp b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
index a6d440f..804f7ba 100644
--- a/llvm/lib/Target/Sparc/SparcISelLowering.cpp
+++ b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
@@ -3183,7 +3183,7 @@
     case 'e':
       return C_RegisterClass;
     case 'I': // SIMM13
-      return C_Other;
+      return C_Immediate;
     }
   }
 
diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
index 78820f5..e7b7a5b 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -956,7 +956,7 @@
     case 'K': // Signed 16-bit constant
     case 'L': // Signed 20-bit displacement (on all targets we support)
     case 'M': // 0x7fffffff
-      return C_Other;
+      return C_Immediate;
 
     default:
       break;
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 8147168..ee25603 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -44875,10 +44875,11 @@
     case 'I':
     case 'J':
     case 'K':
-    case 'L':
-    case 'M':
     case 'N':
     case 'G':
+    case 'L':
+    case 'M':
+      return C_Immediate;
     case 'C':
     case 'e':
     case 'Z':