[llvm] r367636 - Prevent vregs leaking into the MC layer via TargetRegisterClass::contains()

[Daniel Sanders via llvm-commits]

Author: dsanders
Date: Thu Aug  1 16:44:42 2019
New Revision: 367636

URL: http://llvm.org/viewvc/llvm-project?rev=367636&view=rev
Log:
Prevent vregs leaking into the MC layer via TargetRegisterClass::contains()

Summary:
The MC layer doesn't expect to deal with vregs but
TargetRegisterClass::contains() forwards into MCRegisterClass::contains()
and this can cause vregs to turn up in the MC layer APIs. Add guards
against this to prevent this becoming a problem as we replace unsigned
with a new MCRegister object for improved type safety.

Reviewers: arsenm

Subscribers: wdng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65554

Modified:
    llvm/trunk/include/llvm/CodeGen/TargetRegisterInfo.h

Modified: llvm/trunk/include/llvm/CodeGen/TargetRegisterInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/TargetRegisterInfo.h?rev=367636&r1=367635&r2=367636&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/TargetRegisterInfo.h (original)
+++ llvm/trunk/include/llvm/CodeGen/TargetRegisterInfo.h Thu Aug  1 16:44:42 2019
@@ -87,11 +87,20 @@ public:
   /// Return true if the specified register is included in this register class.
   /// This does not include virtual registers.
   bool contains(unsigned Reg) const {
+    /// FIXME: Historically this function has returned false when given vregs
+    ///        but it should probably only receive physical registers
+    if (!Register::isPhysicalRegister(Reg))
+      return false;
     return MC->contains(Reg);
   }
 
   /// Return true if both registers are in this class.
   bool contains(unsigned Reg1, unsigned Reg2) const {
+    /// FIXME: Historically this function has returned false when given a vregs
+    ///        but it should probably only receive physical registers
+    if (!Register::isPhysicalRegister(Reg1) ||
+        !Register::isPhysicalRegister(Reg2))
+      return false;
     return MC->contains(Reg1, Reg2);
   }