[PATCH] D48887: [TableGen] Suppress type validation when parsing pattern fragments

[Ulrich Weigand via Phabricator via llvm-commits]

uweigand created this revision.
uweigand added a reviewer: kparzysz.
Herald added a subscriber: llvm-commits.

Currently, any attempt to define a PatFrag involving any floating-point only (or vector only) node causes a hard assertion failure in TableGen if the current target does not have any floating-point (or vector) types.

This is annoying if you want to provide convenience fragments in common code (e.g. include/llvm/Target/TargetSelectionDAG.td) that is parsed on all platforms, including those that miss such types.

But really, there's no reason not accept this when parsing the fragment -- of course it would be an error for such a target to actually *use* such a fragment anywhere, but as long as it doesn't, I think TableGen shouldn't error out.

The immediate cause of the assertion failure is the test inside the ValidateOnExit destructor.  This patch simply disables that check while infering types during parsing of pattern fragments (only).

If there's a cleaner / simpler way to achieve the same effect, please let me know ...


Repository:
  rL LLVM

https://reviews.llvm.org/D48887

Files:
  utils/TableGen/CodeGenDAGPatterns.cpp
  utils/TableGen/CodeGenDAGPatterns.h


Index: utils/TableGen/CodeGenDAGPatterns.h
===================================================================
--- utils/TableGen/CodeGenDAGPatterns.h
+++ utils/TableGen/CodeGenDAGPatterns.h
@@ -333,9 +333,21 @@
     TypeSetByHwMode &VTS;
   };
 
+  struct SuppressValidation {
+    SuppressValidation(TypeInfer &TI) : Infer(TI), SavedValidate(TI.Validate) {
+      Infer.Validate = false;
+    }
+    ~SuppressValidation() {
+      Infer.Validate = SavedValidate;
+    }
+    TypeInfer &Infer;
+    bool SavedValidate;
+  };
+
   TreePattern &TP;
   unsigned ForceMode;     // Mode to use when set.
   bool CodeGen = false;   // Set during generation of matcher code.
+  bool Validate = true;   // Indicate whether to validate types.
 
 private:
   TypeSetByHwMode getLegalTypes();
Index: utils/TableGen/CodeGenDAGPatterns.cpp
===================================================================
--- utils/TableGen/CodeGenDAGPatterns.cpp
+++ utils/TableGen/CodeGenDAGPatterns.cpp
@@ -808,7 +808,7 @@
 
 #ifndef NDEBUG
 TypeInfer::ValidateOnExit::~ValidateOnExit() {
-  if (!VTS.validate()) {
+  if (Infer.Validate && !VTS.validate()) {
     dbgs() << "Type set is empty for each HW mode:\n"
               "possible type contradiction in the pattern below "
               "(use -print-records with llvm-tblgen to see all "
@@ -3018,9 +3018,15 @@
     ThePat.InlinePatternFragments();
 
     // Infer as many types as possible.  Don't worry about it if we don't infer
-    // all of them, some may depend on the inputs of the pattern.
-    ThePat.InferAllTypes();
-    ThePat.resetError();
+    // all of them, some may depend on the inputs of the pattern.  Also, don't
+    // validate type sets; validation may cause spurious failures e.g. if a
+    // fragment needs floating-point types but the current target does not have
+    // any (this is only an error if that fragment is ever used!).
+    {
+      TypeInfer::SuppressValidation _1(ThePat.getInfer());
+      ThePat.InferAllTypes();
+      ThePat.resetError();
+    }
 
     // If debugging, print out the pattern fragment result.
     LLVM_DEBUG(ThePat.dump());


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