Add an instruction deprecation feature to TableGen.

The 'Deprecated' class allows you to specify a SubtargetFeature that the
instruction is deprecated on.

The 'ComplexDeprecationPredicate' class allows you to define a custom
predicate that is called to check for deprecation.
For example:
  ComplexDeprecationPredicate<"MCR">

would mean you would have to define the following function:
  bool getMCRDeprecationInfo(MCInst &MI, MCSubtargetInfo &STI,
                             std::string &Info)

Which returns 'false' for not deprecated, and 'true' for deprecated
and store the warning message in 'Info'.

The MCTargetAsmParser constructor was chaned to take an extra argument of
the MCInstrInfo class, so out-of-tree targets will need to be changed.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190598 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 19 insertions, 0 deletions

diff --git a/include/llvm/MC/MCInstrDesc.h b/include/llvm/MC/MCInstrDesc.h
index 310f706..84d6380 100644
--- a/include/llvm/MC/MCInstrDesc.h
+++ b/include/llvm/MC/MCInstrDesc.h
@@ -17,6 +17,7 @@
 
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/Support/DataTypes.h"
 
 namespace llvm {
@@ -145,6 +146,10 @@ public:
   const uint16_t *ImplicitUses;  // Registers implicitly read by this instr
   const uint16_t *ImplicitDefs;  // Registers implicitly defined by this instr
   const MCOperandInfo *OpInfo;   // 'NumOperands' entries about operands
+  uint64_t DeprecatedFeatureMask;// Feature bits that this is deprecated on, if any
+  // A complex method to determine is a certain is deprecated or not, and return
+  // the reason for deprecation.
+  bool (*ComplexDeprecationInfo)(MCInst &, MCSubtargetInfo &, std::string &);
 
   /// \brief Returns the value of the specific constraint if
   /// it is set. Returns -1 if it is not set.
@@ -158,6 +163,20 @@ public:
     return -1;
   }
 
+  /// \brief Returns true if a certain instruction is deprecated and if so
+  /// returns the reason in \p Info.
+  bool getDeprecatedInfo(MCInst &MI, MCSubtargetInfo &STI,
+                         std::string &Info) const {
+    if (ComplexDeprecationInfo)
+      return ComplexDeprecationInfo(MI, STI, Info);
+    if (DeprecatedFeatureMask != 0) {
+      // FIXME: it would be nice to include the subtarget feature here.
+      Info = "deprecated";
+      return true;
+    }
+    return false;
+  }
+
   /// \brief Return the opcode number for this descriptor.
   unsigned getOpcode() const {
     return Opcode;