[Macros] Remove ModuleDecl::isInGeneratedBuffer.

This method was misleading. The majority of callers (all but one!) don't want
to unconditionally treat all locations in any macro expansion buffer the
same way, because the code also must handle nested macro expansions. There
is one part of SourceKit (and possibly others) that really do want to ignore
all macro expansions, but those can be handled within SourceKit / IDE code,
because I don't believe this utility is useful in the frontend.

Author: hborla

include/swift/AST/Attr.h

@@ -2584,12 +2584,12 @@ class DeclAttributes {
 
 /// Predicate used to filter attributes to only the original attributes.
 class OrigDeclAttrFilter {
-  ModuleDecl *mod;
+  const Decl *decl;
 
 public:
-  OrigDeclAttrFilter() : mod(nullptr) {}
+  OrigDeclAttrFilter() : decl(nullptr) {}
 
-  OrigDeclAttrFilter(ModuleDecl *mod) : mod(mod) {}
+  OrigDeclAttrFilter(const Decl *decl) : decl(decl) {}
 
   Optional<const DeclAttribute *>
   operator()(const DeclAttribute *Attr) const;
@@ -2611,7 +2611,7 @@ class OrigDeclAttributes {
 public:
   OrigDeclAttributes() : origRange(make_range(DeclAttributes::const_iterator(nullptr), DeclAttributes::const_iterator(nullptr)), OrigDeclAttrFilter()) {}
 
-  OrigDeclAttributes(const DeclAttributes &allAttrs, ModuleDecl *mod) : origRange(make_range(allAttrs.begin(), allAttrs.end()), OrigDeclAttrFilter(mod)) {}
+  OrigDeclAttributes(const DeclAttributes &allAttrs, const Decl *decl) : origRange(make_range(allAttrs.begin(), allAttrs.end()), OrigDeclAttrFilter(decl)) {}
 
   OrigFilteredRange::iterator begin() const { return origRange.begin(); }
   OrigFilteredRange::iterator end() const { return origRange.end(); }

include/swift/AST/Module.h

@@ -406,10 +406,6 @@ class ModuleDecl
   /// \c nullptr if the source location isn't in this module.
   SourceFile *getSourceFileContainingLocation(SourceLoc loc);
 
-  /// Whether the given location is inside a generated buffer, \c false if
-  /// the given location isn't in this module.
-  bool isInGeneratedBuffer(SourceLoc loc);
-
   // Retrieve the buffer ID and source location of the outermost location that
   // caused the generation of the buffer containing \p loc. \p loc and its
   // buffer if it isn't in a generated buffer or has no original location.

lib/AST/Attr.cpp

@@ -853,8 +853,18 @@ SourceLoc DeclAttributes::getStartLoc(bool forModifiers) const {
 
 Optional<const DeclAttribute *>
 OrigDeclAttrFilter::operator()(const DeclAttribute *Attr) const {
-  if (!mod || mod->isInGeneratedBuffer(Attr->AtLoc))
+  auto declLoc = decl->getStartLoc();
+  auto *mod = decl->getModuleContext();
+  auto *declFile = mod->getSourceFileContainingLocation(declLoc);
+  auto *attrFile = mod->getSourceFileContainingLocation(Attr->AtLoc);
+  if (!declFile || !attrFile)
+    return Attr;
+
+  // Only attributes in the same buffer as the declaration they're attached to
+  // are part of the original attribute list.
+  if (declFile->getBufferID() != attrFile->getBufferID())
     return None;
+
   return Attr;
 }
 

lib/AST/Decl.cpp

@@ -368,7 +368,7 @@ StringRef Decl::getDescriptiveKindName(DescriptiveDeclKind K) {
 }
 
 OrigDeclAttributes Decl::getOriginalAttrs() const {
-  return OrigDeclAttributes(getAttrs(), getModuleContext());
+  return OrigDeclAttributes(getAttrs(), this);
 }
 
 DeclAttributes Decl::getSemanticAttrs() const {

lib/AST/Module.cpp

@@ -816,13 +816,6 @@ SourceFile *ModuleDecl::getSourceFileContainingLocation(SourceLoc loc) {
   return foundSourceFile;
 }
 
-bool ModuleDecl::isInGeneratedBuffer(SourceLoc loc) {
-  SourceFile *file = getSourceFileContainingLocation(loc);
-  if (!file)
-    return false;
-  return file->Kind == SourceFileKind::MacroExpansion;
-}
-
 std::pair<unsigned, SourceLoc>
 ModuleDecl::getOriginalLocation(SourceLoc loc) const {
   assert(loc.isValid());

lib/Refactoring/Refactoring.cpp

@@ -649,11 +649,20 @@ renameAvailabilityInfo(const ValueDecl *VD, Optional<RenameRefInfo> RefInfo) {
     AvailKind = RefactorAvailableKind::Unavailable_has_no_name;
   }
 
+  auto isInMacroExpansionBuffer = [](const ValueDecl *VD) -> bool {
+    auto *module = VD->getModuleContext();
+    auto *file = module->getSourceFileContainingLocation(VD->getLoc());
+    if (!file)
+      return false;
+
+    return file->getFulfilledMacroRole() != None;
+  };
+
   if (AvailKind == RefactorAvailableKind::Available) {
     SourceLoc Loc = VD->getLoc();
     if (!Loc.isValid()) {
       AvailKind = RefactorAvailableKind::Unavailable_has_no_location;
-    } else if (VD->getModuleContext()->isInGeneratedBuffer(Loc)) {
+    } else if (isInMacroExpansionBuffer(VD)) {
       AvailKind = RefactorAvailableKind::Unavailable_decl_in_macro;
     }
   }