[clang] Implement resource binding type prefix mismatch diagnostic infrastructure (PR #97103)

[Damyan Pepper via cfe-commits]

================
@@ -437,7 +444,419 @@ void SemaHLSL::handleShaderAttr(Decl *D, const ParsedAttr &AL) {
     D->addAttr(NewAttr);
 }
 
+struct RegisterBindingFlags {
+  bool Resource = false;
+  bool UDT = false;
+  bool Other = false;
+  bool Basic = false;
+
+  bool SRV = false;
+  bool UAV = false;
+  bool CBV = false;
+  bool Sampler = false;
+
+  bool ContainsNumeric = false;
+  bool DefaultGlobals = false;
+};
+
+bool isDeclaredWithinCOrTBuffer(const Decl *decl) {
+  if (!decl)
+    return false;
+
+  // Traverse up the parent contexts
+  const DeclContext *context = decl->getDeclContext();
+  if (isa<HLSLBufferDecl>(context)) {
+    return true;
+  }
+
+  return false;
+}
+
+const CXXRecordDecl *getRecordDeclFromVarDecl(VarDecl *VD) {
+  const Type *Ty = VD->getType()->getPointeeOrArrayElementType();
+  assert(Ty && "Resource class must have an element type.");
+
+  if (const auto *BTy = dyn_cast<BuiltinType>(Ty))
+    return nullptr;
+
+  const CXXRecordDecl *TheRecordDecl = Ty->getAsCXXRecordDecl();
+  assert(TheRecordDecl &&
+         "Resource class should have a resource type declaration.");
+
+  if (auto TDecl = dyn_cast<ClassTemplateSpecializationDecl>(TheRecordDecl))
+    TheRecordDecl = TDecl->getSpecializedTemplate()->getTemplatedDecl();
+  TheRecordDecl = TheRecordDecl->getCanonicalDecl();
+  return TheRecordDecl;
+}
+
+const HLSLResourceAttr *
+getHLSLResourceAttrFromEitherDecl(VarDecl *VD,
+                                  HLSLBufferDecl *CBufferOrTBuffer) {
+
+  if (VD) {
+    const CXXRecordDecl *TheRecordDecl = getRecordDeclFromVarDecl(VD);
+    if (!TheRecordDecl)
+      return nullptr;
+    const auto *Attr = TheRecordDecl->getAttr<HLSLResourceAttr>();
+    return Attr;
+  } else if (CBufferOrTBuffer) {
+    const auto *Attr = CBufferOrTBuffer->getAttr<HLSLResourceAttr>();
+    return Attr;
+  }
+  llvm_unreachable("one of the two conditions should be true.");
+  return nullptr;
+}
+
+void traverseType(QualType T, RegisterBindingFlags &r) {
+  if (T->isIntegralOrEnumerationType() || T->isFloatingType()) {
+    r.ContainsNumeric = true;
+    return;
+  }
+  const RecordType *RT = T->getAs<RecordType>();
+  if (!RT)
+    return;
+
+  RecordDecl *SubRD = RT->getDecl();
+  if (auto TDecl = dyn_cast<ClassTemplateSpecializationDecl>(SubRD)) {
+    auto TheRecordDecl = TDecl->getSpecializedTemplate()->getTemplatedDecl();
+    TheRecordDecl = TheRecordDecl->getCanonicalDecl();
+    const auto *Attr = TheRecordDecl->getAttr<HLSLResourceAttr>();
+    llvm::hlsl::ResourceClass DeclResourceClass = Attr->getResourceClass();
+    switch (DeclResourceClass) {
+    case llvm::hlsl::ResourceClass::SRV:
+      r.SRV = true;
+      break;
+    case llvm::hlsl::ResourceClass::UAV:
+      r.UAV = true;
+      break;
+    case llvm::hlsl::ResourceClass::CBuffer:
+      r.CBV = true;
+      break;
+    case llvm::hlsl::ResourceClass::Sampler:
+      r.Sampler = true;
+      break;
+    }
+  }
+
+  else if (SubRD->isCompleteDefinition()) {
+    for (auto Field : SubRD->fields()) {
+      QualType T = Field->getType();
+      traverseType(T, r);
+    }
+  }
+}
+
+void setResourceClassFlagsFromRecordDecl(RegisterBindingFlags &r,
+                                         const RecordDecl *RD) {
+  if (!RD)
+    return;
+
+  if (RD->isCompleteDefinition()) {
+    for (auto Field : RD->fields()) {
+      QualType T = Field->getType();
+      traverseType(T, r);
+    }
+  }
+}
+
+RegisterBindingFlags HLSLFillRegisterBindingFlags(Sema &S, Decl *D) {
+  RegisterBindingFlags r;
+  if (!isDeclaredWithinCOrTBuffer(D)) {
+    // make sure the type is a basic / numeric type
+    if (VarDecl *v = dyn_cast<VarDecl>(D)) {
+      QualType t = v->getType();
+      // a numeric variable will inevitably end up in $Globals buffer
+      if (t->isIntegralType(S.getASTContext()) || t->isFloatingType())
+        r.DefaultGlobals = true;
+    }
+  }
+  // Cbuffers and Tbuffers are HLSLBufferDecl types
+  HLSLBufferDecl *CBufferOrTBuffer = dyn_cast<HLSLBufferDecl>(D);
+  // Samplers, UAVs, and SRVs are VarDecl types
+  VarDecl *VD = dyn_cast<VarDecl>(D);
+
+  assert(((VD && !CBufferOrTBuffer) || (!VD && CBufferOrTBuffer)) &&
+         "either VD or CBufferOrTBuffer should be set");
+
+  if (CBufferOrTBuffer) {
+    r.Resource = true;
+    if (CBufferOrTBuffer->isCBuffer())
+      r.CBV = true;
+    else
+      r.SRV = true;
+  } else if (VD) {
+    const HLSLResourceAttr *res_attr =
+        getHLSLResourceAttrFromEitherDecl(VD, CBufferOrTBuffer);
+    if (res_attr) {
+      llvm::hlsl::ResourceClass DeclResourceClass =
+          res_attr->getResourceClass();
+      r.Resource = true;
+      switch (DeclResourceClass) {
+      case llvm::hlsl::ResourceClass::SRV: {
+        r.SRV = true;
+        break;
+      }
+      case llvm::hlsl::ResourceClass::UAV: {
+        r.UAV = true;
+        break;
+      }
+      case llvm::hlsl::ResourceClass::CBuffer: {
+        r.CBV = true;
+        break;
+      }
+      case llvm::hlsl::ResourceClass::Sampler: {
+        r.Sampler = true;
+        break;
+      }
+      }
+    } else {
+      if (VD->getType()->isBuiltinType())
+        r.Basic = true;
+      else if (VD->getType()->isAggregateType()) {
+        r.UDT = true;
+        QualType VarType = VD->getType();
+        if (const RecordType *RT = VarType->getAs<RecordType>()) {
+          const RecordDecl *RD = RT->getDecl();
+          // recurse through members, set appropriate resource class flags.
+          setResourceClassFlagsFromRecordDecl(r, RD);
+        }
+      } else
+        r.Other = true;
+    }
+  }
+  return r;
+}
+
+int getRegisterTypeIndex(StringRef Slot) {
+  switch (Slot[0]) {
+  case 't':
+  case 'T':
+    return 0;
+  case 'u':
+  case 'U':
+    return 1;
+  case 'b':
+  case 'B ':
+    return 2;
+  case 's':
+  case 'S':
+    return 3;
+  case 'c':
+  case 'C':
+    return 4;
+  case 'i':
+  case 'I':
+    return 5;
+  default:
+    llvm_unreachable("invalid register type");
+  }
+}
+
+static void ValidateMultipleRegisterAnnotations(Sema &S, Decl *D,
+                                                StringRef &Slot) {
+  // make sure that there are no tworegister annotations
+  // applied to the decl with the same register type
+  bool RegisterTypesDetected[6] = {false};
+  RegisterTypesDetected[getRegisterTypeIndex(Slot)] = true;
+
+  for (auto it = D->attr_begin(); it != D->attr_end(); ++it) {
+    if (HLSLResourceBindingAttr *attr =
+            dyn_cast<HLSLResourceBindingAttr>(*it)) {
+
+      int registerTypeIndex = getRegisterTypeIndex(attr->getSlot());
+      if (RegisterTypesDetected[registerTypeIndex]) {
+        S.Diag(D->getLocation(),
+               diag::err_hlsl_conflicting_register_annotations)
+            << attr->getSlot().substr(0, 1);
+      } else {
+        RegisterTypesDetected[registerTypeIndex] = true;
+      }
+    }
+  }
+}
+
+std::string getHLSLResourceTypeStr(Sema &S, Decl *D) {
+  VarDecl *VD = dyn_cast<VarDecl>(D);
+  HLSLBufferDecl *CBufferOrTBuffer = dyn_cast<HLSLBufferDecl>(D);
+
+  if (VD) {
+    QualType QT = VD->getType();
+    PrintingPolicy PP = S.getPrintingPolicy();
+    return QualType::getAsString(QT.split(), PP);
+  } else {
+    return CBufferOrTBuffer->isCBuffer() ? "cbuffer" : "tbuffer";
+  }
+}
+
+static void DiagnoseHLSLResourceRegType(Sema &S, SourceLocation &ArgLoc,
+                                        Decl *D, StringRef &Slot) {
+
+  // Samplers, UAVs, and SRVs are VarDecl types
+  VarDecl *VD = dyn_cast<VarDecl>(D);
+  // Cbuffers and Tbuffers are HLSLBufferDecl types
+  HLSLBufferDecl *CBufferOrTBuffer = dyn_cast<HLSLBufferDecl>(D);
+
+  // exactly one of these two types should be set
+  assert(((VD && !CBufferOrTBuffer) || (!VD && CBufferOrTBuffer)) &&
+         "either VD or CBufferOrTBuffer should be set");
+
+  RegisterBindingFlags f = HLSLFillRegisterBindingFlags(S, D);
+  assert((int)f.Other + (int)f.Resource + (int)f.Basic + (int)f.UDT == 1 &&
+         "only one resource analysis result should be expected");
+
+  std::string registerType(Slot.substr(0, 1));
----------------
damyanp wrote:

How sure are you that constructing this string doesn't allocate memory?  It'd be better to only construct the `std::string` if you need it.

https://github.com/llvm/llvm-project/pull/97103