[TableGen] Improve error reporting

[evandro]

Summary

When searching for a resource unit, use the reference location instead of the definition location in case of an error.

[javed.absar]

Thanks for this. Is it possible to put a test? If not, perhaps you can share the output generated for a purposely failing case here (by omitting a referenced resource).

[evandro]

Before this patch, a typical output would be like:

.../llvm/lib/Target/AArch64/AArch64SchedA57.td:49:3: error: No ProcessorResources associated with A57UnitV
  def A57UnitV : ProcResGroup<[A57UnitX, A57UnitW]>;    // Type V micro-ops
  ^

Whereas after this patch, the offending line is output instead:

.../llvm/lib/Target/AArch64/AArch64SchedM1.td:76:1: error: No ProcessorResources associated with A57UnitV
def M1WriteA1 : SchedWriteRes<[A57UnitV]> { let Latency = 1; }
^

The latter is obviously clear what the issue is, unlike the former.

[javed.absar]

LGTM. Thanks for this.

llvm/utils/TableGen/CodeGenSchedule.h

unsigned addSchedClass(Record *ItinDef, ArrayRef<unsigned> OperWrites,
                          ArrayRef<unsigned> OperReads,
                          ArrayRef<unsigned> ProcIndices);
 
   unsigned findOrInsertRW(ArrayRef<unsigned> Seq, bool IsRead);
 
   unsigned findSchedClassIdx(Record *ItinClassDef, ArrayRef<unsigned> Writes,
                              ArrayRef<unsigned> Reads) const;
 
-  Record *findProcResUnits(Record *ProcResKind,
-                           const CodeGenProcModel &PM) const;
+  Record *findProcResUnits(Record *ProcResKind, const CodeGenProcModel &PM,
+                           ArrayRef<SMLoc> Loc) const;
 
 private:
   void collectProcModels();
 
   // Initialize a new processor model if it is unique.
   void addProcModel(Record *ProcDef);
 
   void collectSchedRW();
private:
   void collectItinProcResources(Record *ItinClassDef);
 
   void collectRWResources(unsigned RWIdx, bool IsRead,
                           ArrayRef<unsigned> ProcIndices);
 
   void collectRWResources(ArrayRef<unsigned> Writes, ArrayRef<unsigned> Reads,
                           ArrayRef<unsigned> ProcIndices);
 
-  void addProcResource(Record *ProcResourceKind, CodeGenProcModel &PM);
+  void addProcResource(Record *ProcResourceKind, CodeGenProcModel &PM,
+                       ArrayRef<SMLoc> Loc);
 
   void addWriteRes(Record *ProcWriteResDef, unsigned PIdx);
 
   void addReadAdvance(Record *ProcReadAdvanceDef, unsigned PIdx);
 };
 
 } // namespace llvm
 
 #endif

llvm/utils/TableGen/CodeGenSchedule.cpp

for (unsigned Idx : Writes)
     collectRWResources(Idx, /*IsRead=*/false, ProcIndices);
 
   for (unsigned Idx : Reads)
     collectRWResources(Idx, /*IsRead=*/true, ProcIndices);
 }
 
 // Find the processor's resource units for this kind of resource.
 Record *CodeGenSchedModels::findProcResUnits(Record *ProcResKind,
-                                             const CodeGenProcModel &PM) const {
+                                             const CodeGenProcModel &PM,
+                                             ArrayRef<SMLoc> Loc) const {
   if (ProcResKind->isSubClassOf("ProcResourceUnits"))
     return ProcResKind;
 
   Record *ProcUnitDef = nullptr;
   assert(!ProcResourceDefs.empty());
   assert(!ProcResGroups.empty());
 
   for (Record *ProcResDef : ProcResourceDefs) {
     if (ProcResDef->getValueAsDef("Kind") == ProcResKind
         && ProcResDef->getValueAsDef("SchedModel") == PM.ModelDef) {
       if (ProcUnitDef) {
-        PrintFatalError(ProcResDef->getLoc(),
+        PrintFatalError(Loc,
                         "Multiple ProcessorResourceUnits associated with "
                         + ProcResKind->getName());
       }
       ProcUnitDef = ProcResDef;
     }
   }
   for (Record *ProcResGroup : ProcResGroups) {
     if (ProcResGroup == ProcResKind
         && ProcResGroup->getValueAsDef("SchedModel") == PM.ModelDef) {
       if (ProcUnitDef) {
-        PrintFatalError((ProcResGroup)->getLoc(),
+        PrintFatalError(Loc,
                         "Multiple ProcessorResourceUnits associated with "
                         + ProcResKind->getName());
       }
       ProcUnitDef = ProcResGroup;
     }
   }
   if (!ProcUnitDef) {
-    PrintFatalError(ProcResKind->getLoc(),
+    PrintFatalError(Loc,
                     "No ProcessorResources associated with "
                     + ProcResKind->getName());
   }
   return ProcUnitDef;
 }
 
 // Iteratively add a resource and its super resources.
 void CodeGenSchedModels::addProcResource(Record *ProcResKind,
-                                         CodeGenProcModel &PM) {
+                                         CodeGenProcModel &PM,
+                                         ArrayRef<SMLoc> Loc) {
   while (true) {
-    Record *ProcResUnits = findProcResUnits(ProcResKind, PM);
+    Record *ProcResUnits = findProcResUnits(ProcResKind, PM, Loc);
 
     // See if this ProcResource is already associated with this processor.
     if (is_contained(PM.ProcResourceDefs, ProcResUnits))
       return;
 
     PM.ProcResourceDefs.push_back(ProcResUnits);
     if (ProcResUnits->isSubClassOf("ProcResGroup"))
       return;
void CodeGenSchedModels::addWriteRes(Record *ProcWriteResDef, unsigned PIdx) {
   if (is_contained(WRDefs, ProcWriteResDef))
     return;
   WRDefs.push_back(ProcWriteResDef);
 
   // Visit ProcResourceKinds referenced by the newly discovered WriteRes.
   RecVec ProcResDefs = ProcWriteResDef->getValueAsListOfDefs("ProcResources");
   for (RecIter WritePRI = ProcResDefs.begin(), WritePRE = ProcResDefs.end();
        WritePRI != WritePRE; ++WritePRI) {
-    addProcResource(*WritePRI, ProcModels[PIdx]);
+    addProcResource(*WritePRI, ProcModels[PIdx], ProcWriteResDef->getLoc());
   }
 }
 
 // Add resources for a ReadAdvance to this processor if they don't exist.
 void CodeGenSchedModels::addReadAdvance(Record *ProcReadAdvanceDef,
                                         unsigned PIdx) {
   RecVec &RADefs = ProcModels[PIdx].ReadAdvanceDefs;
   if (is_contained(RADefs, ProcReadAdvanceDef))

llvm/utils/TableGen/SubtargetEmitter.cpp

if (PRDef->isSubClassOf("ProcResGroup")) {
       RecVec ResUnits = PRDef->getValueAsListOfDefs("Resources");
       for (Record *RU : ResUnits) {
         NumUnits += RU->getValueAsInt("NumUnits");
       }
     }
     else {
       // Find the SuperIdx
       if (PRDef->getValueInit("Super")->isComplete()) {
-        SuperDef = SchedModels.findProcResUnits(
-          PRDef->getValueAsDef("Super"), ProcModel);
+        SuperDef =
+            SchedModels.findProcResUnits(PRDef->getValueAsDef("Super"),
+                                         ProcModel, PRDef->getLoc());
         SuperIdx = ProcModel.getProcResourceIdx(SuperDef);
       }
       NumUnits = PRDef->getValueAsInt("NumUnits");
     }
     // Emit the ProcResourceDesc
     OS << "  {DBGFIELD(\"" << PRDef->getName() << "\") ";
     if (PRDef->getName().size() < 15)
       OS.indent(15 - PRDef->getName().size());
void SubtargetEmitter::ExpandProcResources(RecVec &PRVec,
   Cycles.resize(PRVec.size(), 1);
   for (unsigned i = 0, e = PRVec.size(); i != e; ++i) {
     Record *PRDef = PRVec[i];
     RecVec SubResources;
     if (PRDef->isSubClassOf("ProcResGroup"))
       SubResources = PRDef->getValueAsListOfDefs("Resources");
     else {
       SubResources.push_back(PRDef);
-      PRDef = SchedModels.findProcResUnits(PRVec[i], PM);
+      PRDef = SchedModels.findProcResUnits(PRDef, PM, PRDef->getLoc());
       for (Record *SubDef = PRDef;
            SubDef->getValueInit("Super")->isComplete();) {
         if (SubDef->isSubClassOf("ProcResGroup")) {
           // Disallow this for simplicitly.
           PrintFatalError(SubDef->getLoc(), "Processor resource group "
                           " cannot be a super resources.");
         }
         Record *SuperDef =
-          SchedModels.findProcResUnits(SubDef->getValueAsDef("Super"), PM);
+            SchedModels.findProcResUnits(SubDef->getValueAsDef("Super"), PM,
+                                         SubDef->getLoc());
         PRVec.push_back(SuperDef);
         Cycles.push_back(Cycles[i]);
         SubDef = SuperDef;
       }
     }
     for (Record *PR : PM.ProcResourceDefs) {
       if (PR == PRDef || !PR->isSubClassOf("ProcResGroup"))
         continue;