vendor/llvm/llvm-trunk-r301441

1 files changed, 34 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/GlobalISel/InstructionSelector.h b/include/llvm/CodeGen/GlobalISel/InstructionSelector.h
index 911e8756070b2..899563acc330b 100644
--- a/include/llvm/CodeGen/GlobalISel/InstructionSelector.h
+++ b/include/llvm/CodeGen/GlobalISel/InstructionSelector.h
@@ -18,20 +18,52 @@
 
 #include "llvm/ADT/Optional.h"
 #include <cstdint>
+#include <bitset>
+#include <functional>
 
 namespace llvm {
 class MachineInstr;
+class MachineInstrBuilder;
+class MachineFunction;
 class MachineOperand;
 class MachineRegisterInfo;
 class RegisterBankInfo;
 class TargetInstrInfo;
 class TargetRegisterInfo;
 
+/// Container class for CodeGen predicate results.
+/// This is convenient because std::bitset does not have a constructor
+/// with an initializer list of set bits.
+///
+/// Each InstructionSelector subclass should define a PredicateBitset class with:
+///   const unsigned MAX_SUBTARGET_PREDICATES = 192;
+///   using PredicateBitset = PredicateBitsetImpl<MAX_SUBTARGET_PREDICATES>;
+/// and updating the constant to suit the target. Tablegen provides a suitable
+/// definition for the predicates in use in <Target>GenGlobalISel.inc when
+/// GET_GLOBALISEL_PREDICATE_BITSET is defined.
+template <std::size_t MaxPredicates>
+class PredicateBitsetImpl : public std::bitset<MaxPredicates> {
+public:
+  // Cannot inherit constructors because it's not supported by VC++..
+  PredicateBitsetImpl() = default;
+
+  PredicateBitsetImpl(const std::bitset<MaxPredicates> &B)
+      : std::bitset<MaxPredicates>(B) {}
+
+  PredicateBitsetImpl(std::initializer_list<unsigned> Init) {
+    for (auto I : Init)
+      std::bitset<MaxPredicates>::set(I);
+  }
+};
+
 /// Provides the logic to select generic machine instructions.
 class InstructionSelector {
 public:
   virtual ~InstructionSelector() {}
 
+  /// This is executed before selecting a function.
+  virtual void beginFunction(const MachineFunction &MF) {}
+
   /// Select the (possibly generic) instruction \p I to only use target-specific
   /// opcodes. It is OK to insert multiple instructions, but they cannot be
   /// generic pre-isel instructions.
@@ -46,6 +78,8 @@ public:
   virtual bool select(MachineInstr &I) const = 0;
 
 protected:
+  typedef std::function<void(MachineInstrBuilder &)> ComplexRendererFn;
+
   InstructionSelector();
 
   /// Mutate the newly-selected instruction \p I to constrain its (possibly