[GlobalISel][TableGen] Add support for SDNodeXForm

Summary:
This patch adds CustomRenderer which renders the matched
operands to the specified instruction.

Targets can enable the matching of SDNodeXForm by adding
a definition that inherits from GICustomOperandRenderer and
GISDNodeXFormEquiv as follows.

def gi_imm8 : GICustomOperandRenderer<"renderImm8”>,
                       GISDNodeXFormEquiv<imm8_xform>;

Custom renderer functions should be of the form:
void render(MachineInstrBuilder &MIB, const MachineInstr &I);

Reviewers: dsanders, ab, rovka

Reviewed By: dsanders

Subscribers: kristof.beyls, javed.absar, llvm-commits, mgrang, qcolombet

Differential Revision: https://reviews.llvm.org/D42012

llvm-svn: 322582

1 files changed, 106 insertions, 26 deletions

diff --git a/llvm/utils/TableGen/GlobalISelEmitter.cpp b/llvm/utils/TableGen/GlobalISelEmitter.cpp
index c7d662db5a2..b4073b15daa 100644
--- a/llvm/utils/TableGen/GlobalISelEmitter.cpp
+++ b/llvm/utils/TableGen/GlobalISelEmitter.cpp
@@ -260,6 +260,11 @@ std::string explainOperator(Record *Operator) {
             ")")
         .str();
 
+  if (Operator->isSubClassOf("SDNodeXForm"))
+    return (" (Operator is an unmapped SDNodeXForm, " + Operator->getName() +
+            ")")
+        .str();
+
   return (" (Operator " + Operator->getName() + " not understood)").str();
 }
 
@@ -315,12 +320,7 @@ static Error isTrivialOperatorNode(const TreePatternNode *N) {
     break;
   }
 
-  if (N->getTransformFn()) {
-    Explanation += Separator + "Has a transform function";
-    Separator = ", ";
-  }
-
-  if (!HasUnsupportedPredicate && !N->getTransformFn())
+  if (!HasUnsupportedPredicate)
     return Error::success();
 
   return failedImport(Explanation);
@@ -1706,7 +1706,8 @@ public:
     OR_Imm,
     OR_Register,
     OR_TempRegister,
-    OR_ComplexPattern
+    OR_ComplexPattern,
+    OR_Custom
   };
 
 protected:
@@ -2018,6 +2019,38 @@ public:
   }
 };
 
+class CustomRenderer : public OperandRenderer {
+protected:
+  unsigned InsnID;
+  const Record &Renderer;
+  /// The name of the operand.
+  const std::string SymbolicName;
+
+public:
+  CustomRenderer(unsigned InsnID, const Record &Renderer,
+                 StringRef SymbolicName)
+      : OperandRenderer(OR_Custom), InsnID(InsnID), Renderer(Renderer),
+        SymbolicName(SymbolicName) {}
+
+  static bool classof(const OperandRenderer *R) {
+    return R->getKind() == OR_Custom;
+  }
+
+  void emitRenderOpcodes(MatchTable &Table, RuleMatcher &Rule) const override {
+    const InstructionMatcher &InsnMatcher =
+        Rule.getInstructionMatcher(SymbolicName);
+    unsigned OldInsnVarID = Rule.getInsnVarID(InsnMatcher);
+    Table << MatchTable::Opcode("GIR_CustomRenderer")
+          << MatchTable::Comment("InsnID") << MatchTable::IntValue(InsnID)
+          << MatchTable::Comment("OldInsnID")
+          << MatchTable::IntValue(OldInsnVarID)
+          << MatchTable::Comment("Renderer")
+          << MatchTable::NamedValue(
+                 "GICR_" + Renderer.getValueAsString("RendererFn").str())
+          << MatchTable::Comment(SymbolicName) << MatchTable::LineBreak;
+  }
+};
+
 /// An action taken when all Matcher predicates succeeded for a parent rule.
 ///
 /// Typical actions include:
@@ -2541,6 +2574,11 @@ private:
   /// GIComplexPatternEquiv.
   DenseMap<const Record *, const Record *> ComplexPatternEquivs;
 
+  /// Keep track of the equivalence between SDNodeXForm's and
+  /// GICustomOperandRenderer. Map entries are specified by subclassing
+  /// GISDNodeXFormEquiv.
+  DenseMap<const Record *, const Record *> SDNodeXFormEquivs;
+
   // Map of predicates to their subtarget features.
   SubtargetFeatureInfoMap SubtargetFeatures;
 
@@ -2645,6 +2683,14 @@ void GlobalISelEmitter::gatherNodeEquivs() {
       continue;
     ComplexPatternEquivs[SelDAGEquiv] = Equiv;
  }
+
+ assert(SDNodeXFormEquivs.empty());
+ for (Record *Equiv : RK.getAllDerivedDefinitions("GISDNodeXFormEquiv")) {
+   Record *SelDAGEquiv = Equiv->getValueAsDef("SelDAGEquivalent");
+   if (!SelDAGEquiv)
+     continue;
+   SDNodeXFormEquivs[SelDAGEquiv] = Equiv;
+ }
 }
 
 Record *GlobalISelEmitter::findNodeEquiv(Record *N) const {
@@ -2986,10 +3032,6 @@ Error GlobalISelEmitter::importChildMatcher(RuleMatcher &Rule,
 Expected<action_iterator> GlobalISelEmitter::importExplicitUseRenderer(
     action_iterator InsertPt, RuleMatcher &Rule, BuildMIAction &DstMIBuilder,
     TreePatternNode *DstChild) {
-  if (DstChild->getTransformFn() != nullptr) {
-    return failedImport("Dst pattern child has transform fn " +
-                        DstChild->getTransformFn()->getName());
-  }
 
   const auto &SubOperand = Rule.getComplexSubOperand(DstChild->getName());
   if (SubOperand.hasValue()) {
@@ -3000,6 +3042,18 @@ Expected<action_iterator> GlobalISelEmitter::importExplicitUseRenderer(
   }
 
   if (!DstChild->isLeaf()) {
+
+    if (DstChild->getOperator()->isSubClassOf("SDNodeXForm")) {
+      auto Child = DstChild->getChild(0);
+      auto I = SDNodeXFormEquivs.find(DstChild->getOperator());
+      if (I != SDNodeXFormEquivs.end()) {
+        DstMIBuilder.addRenderer<CustomRenderer>(*I->second, Child->getName());
+        return InsertPt;
+      }
+      return failedImport("SDNodeXForm " + Child->getName() +
+                          " has no custom renderer");
+    }
+
     // We accept 'bb' here. It's an operator because BasicBlockSDNode isn't
     // inline, but in MI it's just another operand.
     if (DstChild->getOperator()->isSubClassOf("SDNode")) {
@@ -3104,10 +3158,6 @@ Expected<action_iterator> GlobalISelEmitter::importExplicitUseRenderer(
       return InsertPt;
     }
 
-    if (ChildRec->isSubClassOf("SDNodeXForm"))
-      return failedImport("Dst pattern child def is an unsupported tablegen "
-                          "class (SDNodeXForm)");
-
     return failedImport(
         "Dst pattern child def is an unsupported tablegen class");
   }
@@ -3652,14 +3702,19 @@ void GlobalISelEmitter::run(raw_ostream &OS) {
     Rules.push_back(std::move(MatcherOrErr.get()));
   }
 
+  // Comparison function to order records by name.
+  auto orderByName = [](const Record *A, const Record *B) {
+    return A->getName() < B->getName();
+  };
+
   std::vector<Record *> ComplexPredicates =
       RK.getAllDerivedDefinitions("GIComplexOperandMatcher");
-  std::sort(ComplexPredicates.begin(), ComplexPredicates.end(),
-            [](const Record *A, const Record *B) {
-              if (A->getName() < B->getName())
-                return true;
-              return false;
-            });
+  std::sort(ComplexPredicates.begin(), ComplexPredicates.end(), orderByName);
+
+  std::vector<Record *> CustomRendererFns =
+      RK.getAllDerivedDefinitions("GICustomOperandRenderer");
+  std::sort(CustomRendererFns.begin(), CustomRendererFns.end(), orderByName);
+
   unsigned MaxTemporaries = 0;
   for (const auto &Rule : Rules)
     MaxTemporaries = std::max(MaxTemporaries, Rule.countRendererFns());
@@ -3677,10 +3732,18 @@ void GlobalISelEmitter::run(raw_ostream &OS) {
         "ComplexRendererFns("
      << Target.getName()
      << "InstructionSelector::*ComplexMatcherMemFn)(MachineOperand &) const;\n"
-     << "  const MatcherInfoTy<PredicateBitset, ComplexMatcherMemFn> "
-        "MatcherInfo;\n"
-     << "  static " << Target.getName()
+
+     << "  typedef void(" << Target.getName()
+     << "InstructionSelector::*CustomRendererFn)(MachineInstrBuilder &, const "
+        "MachineInstr&) "
+        "const;\n"
+     << "  const ISelInfoTy<PredicateBitset, ComplexMatcherMemFn, "
+        "CustomRendererFn> "
+        "ISelInfo;\n";
+  OS << "  static " << Target.getName()
      << "InstructionSelector::ComplexMatcherMemFn ComplexPredicateFns[];\n"
+     << "  static " << Target.getName()
+     << "InstructionSelector::CustomRendererFn CustomRenderers[];\n"
      << "bool testImmPredicate_I64(unsigned PredicateID, int64_t Imm) const "
         "override;\n"
      << "bool testImmPredicate_APInt(unsigned PredicateID, const APInt &Imm) "
@@ -3691,7 +3754,8 @@ void GlobalISelEmitter::run(raw_ostream &OS) {
 
   OS << "#ifdef GET_GLOBALISEL_TEMPORARIES_INIT\n"
      << ", State(" << MaxTemporaries << "),\n"
-     << "MatcherInfo({TypeObjects, FeatureBitsets, ComplexPredicateFns})\n"
+     << "ISelInfo({TypeObjects, FeatureBitsets, ComplexPredicateFns, "
+        "CustomRenderers})\n"
      << "#endif // ifdef GET_GLOBALISEL_TEMPORARIES_INIT\n\n";
 
   OS << "#ifdef GET_GLOBALISEL_IMPL\n";
@@ -3821,6 +3885,22 @@ void GlobalISelEmitter::run(raw_ostream &OS) {
        << ", // " << Record->getName() << "\n";
   OS << "};\n\n";
 
+  OS << "// Custom renderers.\n"
+     << "enum {\n"
+     << "  GICR_Invalid,\n";
+  for (const auto &Record : CustomRendererFns)
+    OS << "  GICR_" << Record->getValueAsString("RendererFn") << ", \n";
+  OS << "};\n";
+
+  OS << Target.getName() << "InstructionSelector::CustomRendererFn\n"
+     << Target.getName() << "InstructionSelector::CustomRenderers[] = {\n"
+     << "  nullptr, // GICP_Invalid\n";
+  for (const auto &Record : CustomRendererFns)
+    OS << "  &" << Target.getName()
+       << "InstructionSelector::" << Record->getValueAsString("RendererFn")
+       << ", // " << Record->getName() << "\n";
+  OS << "};\n\n";
+
   OS << "bool " << Target.getName()
      << "InstructionSelector::selectImpl(MachineInstr &I, CodeGenCoverage "
         "&CoverageInfo) const {\n"
@@ -3862,7 +3942,7 @@ void GlobalISelEmitter::run(raw_ostream &OS) {
   }
   Table << MatchTable::Opcode("GIM_Reject") << MatchTable::LineBreak;
   Table.emitDeclaration(OS);
-  OS << "  if (executeMatchTable(*this, OutMIs, State, MatcherInfo, ";
+  OS << "  if (executeMatchTable(*this, OutMIs, State, ISelInfo, ";
   Table.emitUse(OS);
   OS << ", TII, MRI, TRI, RBI, AvailableFeatures, CoverageInfo)) {\n"
      << "    return true;\n"