Replace in_cxx_method_body with an extensible use-flag

This makes it possible to pass more context information about a use
from the detection phase to later IWYU analysis phases.

6 files changed, 59 insertions, 21 deletions

diff --git a/iwyu.cc b/iwyu.cc
index 6ed403b..f41dbc5 100644
--- a/iwyu.cc
+++ b/iwyu.cc
@@ -1400,7 +1400,7 @@ class IwyuBaseAstVisitor : public BaseAstVisitor<Derived> {
             preprocessor_info().FileInfoFor(macro_def_file);
         file_info->ReportForwardDeclareUse(
             spelling_loc, fwd_decl,
-            IsNodeInsideCXXMethodBody(current_ast_node()), nullptr);
+            ComputeUseFlags(current_ast_node()), nullptr);
         break;
       }
     }
@@ -1649,7 +1649,7 @@ class IwyuBaseAstVisitor : public BaseAstVisitor<Derived> {
     used_loc = GetCanonicalUseLocation(used_loc, target_decl);
     const FileEntry* used_in = GetFileEntry(used_loc);
     preprocessor_info().FileInfoFor(used_in)->ReportFullSymbolUse(
-        used_loc, target_decl, IsNodeInsideCXXMethodBody(current_ast_node()),
+        used_loc, target_decl, ComputeUseFlags(current_ast_node()),
         comment);
 
     // Sometimes using a decl drags in a few other uses as well:
@@ -1668,7 +1668,7 @@ class IwyuBaseAstVisitor : public BaseAstVisitor<Derived> {
         = GetUsingDeclarationOf(used_decl, 
               GetDeclContext(current_ast_node()))) {
       preprocessor_info().FileInfoFor(used_in)->ReportUsingDeclUse(
-          used_loc, using_decl, IsNodeInsideCXXMethodBody(current_ast_node()),
+          used_loc, using_decl, ComputeUseFlags(current_ast_node()),
           "(for using decl)");
     }
 
@@ -1720,7 +1720,7 @@ class IwyuBaseAstVisitor : public BaseAstVisitor<Derived> {
     used_loc = GetCanonicalUseLocation(used_loc, target_decl);
     const FileEntry* used_in = GetFileEntry(used_loc);
     preprocessor_info().FileInfoFor(used_in)->ReportForwardDeclareUse(
-        used_loc, target_decl, IsNodeInsideCXXMethodBody(current_ast_node()),
+        used_loc, target_decl, ComputeUseFlags(current_ast_node()),
         comment);
 
     // If we're a use that depends on a using declaration, make sure
@@ -1729,7 +1729,7 @@ class IwyuBaseAstVisitor : public BaseAstVisitor<Derived> {
         = GetUsingDeclarationOf(used_decl, 
               GetDeclContext(current_ast_node()))) {
       preprocessor_info().FileInfoFor(used_in)->ReportUsingDeclUse(
-          used_loc, using_decl, IsNodeInsideCXXMethodBody(current_ast_node()),
+          used_loc, using_decl, ComputeUseFlags(current_ast_node()),
           "(for using decl)");
     }
   }
diff --git a/iwyu_ast_util.cc b/iwyu_ast_util.cc
index ea7919b..03e3dbf 100644
--- a/iwyu_ast_util.cc
+++ b/iwyu_ast_util.cc
@@ -262,6 +262,15 @@ bool IsNodeInsideCXXMethodBody(const ASTNode* ast_node) {
   return false;
 }
 
+UseFlags ComputeUseFlags(const ASTNode* ast_node) {
+  UseFlags flags = UF_None;
+
+  if (IsNodeInsideCXXMethodBody(ast_node))
+    flags |= UF_InCxxMethodBody;
+
+  return flags;
+}
+
 bool IsNestedClassAsWritten(const ASTNode* ast_node) {
   return (ast_node->IsA<RecordDecl>() &&
           (ast_node->ParentIsA<CXXRecordDecl>() ||
diff --git a/iwyu_ast_util.h b/iwyu_ast_util.h
index dd3f5e0..847c68e 100644
--- a/iwyu_ast_util.h
+++ b/iwyu_ast_util.h
@@ -16,6 +16,7 @@
 #include <set>                          // for set
 #include <string>                       // for string
 
+#include "iwyu_use_flags.h"
 #include "port.h"  // for CHECK_
 #include "llvm/Support/Casting.h"
 #include "clang/AST/DeclBase.h"
@@ -386,6 +387,10 @@ bool IsQualifiedNameNode(const ASTNode* ast_node);
 // implicitly), or the implicit (non-body) code of a destructor.
 bool IsNodeInsideCXXMethodBody(const ASTNode* ast_node);
 
+// Return UseFlags for the current node.
+// These flags provide context around the use to help later IWYU analysis,
+UseFlags ComputeUseFlags(const ASTNode* ast_node);
+
 // Return true if we're a nested class as written, that is, we're a
 // class decl inside another class decl.  The parent class may be
 // templated, but we should not be.  (We could extend the function to
diff --git a/iwyu_output.cc b/iwyu_output.cc
index 0c66010..cefb41f 100644
--- a/iwyu_output.cc
+++ b/iwyu_output.cc
@@ -237,7 +237,7 @@ string GetShortNameAsString(const clang::NamedDecl* named_decl) {
 
 // Holds information about a single full or fwd-decl use of a symbol.
 OneUse::OneUse(const NamedDecl* decl, SourceLocation use_loc,
-               OneUse::UseKind use_kind, bool in_cxx_method_body,
+               OneUse::UseKind use_kind, UseFlags flags,
                const char* comment)
     : symbol_name_(internal::GetQualifiedNameAsString(decl)),
       short_symbol_name_(internal::GetShortNameAsString(decl)),
@@ -247,7 +247,7 @@ OneUse::OneUse(const NamedDecl* decl, SourceLocation use_loc,
       decl_filepath_(GetFilePath(decl_file_)),
       use_loc_(use_loc),
       use_kind_(use_kind),             // full use or fwd-declare use
-      in_cxx_method_body_(in_cxx_method_body),
+      use_flags_(flags),
       comment_(comment ? comment : ""),
       ignore_use_(false),
       is_iwyu_violation_(false) {
@@ -263,7 +263,7 @@ OneUse::OneUse(const string& symbol_name, const FileEntry* dfn_file,
       decl_filepath_(dfn_filepath),
       use_loc_(use_loc),
       use_kind_(kFullUse),
-      in_cxx_method_body_(false),
+      use_flags_(UF_None),
       ignore_use_(false),
       is_iwyu_violation_(false) {
   // Sometimes dfn_filepath is actually a fully quoted include.  In
@@ -574,13 +574,13 @@ static void LogSymbolUse(const string& prefix, const OneUse& use) {
 
 void IwyuFileInfo::ReportFullSymbolUse(SourceLocation use_loc,
                                        const NamedDecl* decl,
-                                       bool in_cxx_method_body,
+                                       UseFlags flags,
                                        const char* comment) {
   if (decl) {
     // Since we need the full symbol, we need the decl's definition-site.
     decl = GetDefinitionAsWritten(decl);
     symbol_uses_.push_back(OneUse(decl, use_loc, OneUse::kFullUse,
-                                  in_cxx_method_body, comment));
+                                  flags, comment));
     LogSymbolUse("Marked full-info use of decl", symbol_uses_.back());
   }
 }
@@ -617,7 +617,7 @@ void IwyuFileInfo::ReportKnownDesiredFile(const FileEntry* included_file) {
 
 void IwyuFileInfo::ReportForwardDeclareUse(SourceLocation use_loc,
                                            const NamedDecl* decl,
-                                           bool in_cxx_method_body,
+                                           UseFlags flags,
                                            const char* comment) {
   if (!decl)
     return;
@@ -626,13 +626,13 @@ void IwyuFileInfo::ReportForwardDeclareUse(SourceLocation use_loc,
   // happened here, replace the friend with a real fwd decl.
   decl = GetNonfriendClassRedecl(decl);
   symbol_uses_.push_back(OneUse(decl, use_loc, OneUse::kForwardDeclareUse,
-                                in_cxx_method_body, comment));
+                                flags, comment));
   LogSymbolUse("Marked fwd-decl use of decl", symbol_uses_.back());
 }
 
 void IwyuFileInfo::ReportUsingDeclUse(SourceLocation use_loc,
                                       const UsingDecl* using_decl,
-                                      bool in_cxx_method_body,
+                                      UseFlags flags,
                                       const char* comment) {  
   // If accessing a symbol through a using decl in the same file that contains
   // the using decl, we must mark the using decl as referenced. At the end of
@@ -648,7 +648,7 @@ void IwyuFileInfo::ReportUsingDeclUse(SourceLocation use_loc,
   // When a symbol is accessed through a using decl, we must report
   // that as a full use of the using decl because whatever file that
   // using decl is in is now required.
-  ReportFullSymbolUse(use_loc, using_decl, in_cxx_method_body, comment);
+  ReportFullSymbolUse(use_loc, using_decl, flags, comment);
 }
 
 // Given a collection of symbol-uses for symbols defined in various
@@ -1970,7 +1970,7 @@ void IwyuFileInfo::ResolvePendingAnalysis() {
       if (using_decl->shadow_size() > 0) {
         ReportForwardDeclareUse(using_decl->getUsingLoc(),
                                 using_decl->shadow_begin()->getTargetDecl(),
-                                /* in_cxx_method_body */ false,
+                                /* flags */ UF_None,
                                 "(for un-referenced using)");
       }
     }
diff --git a/iwyu_output.h b/iwyu_output.h
index 190a0f6..f0d2db4 100644
--- a/iwyu_output.h
+++ b/iwyu_output.h
@@ -22,6 +22,7 @@
 #include <vector>                       // for vector
 
 #include "iwyu_stl_util.h"
+#include "iwyu_use_flags.h"
 #include "port.h"  // for CHECK_
 #include "clang/AST/Decl.h"
 #include "clang/Basic/SourceLocation.h"
@@ -50,7 +51,7 @@ class OneUse {
   OneUse(const clang::NamedDecl* decl,
          clang::SourceLocation use_loc,
          UseKind use_kind,
-         bool in_cxx_method_body,
+         UseFlags flags,
          const char* comment);
   // Both dfn_file and dfn_filepath are specified to allow to create OneUse
   // with dfn_filepath and without dfn_file.  For example, in
@@ -70,7 +71,7 @@ class OneUse {
   clang::SourceLocation use_loc() const { return use_loc_; }
   clang::SourceLocation decl_loc() const { return decl_loc_; }
   bool is_full_use() const { return use_kind_ == kFullUse; }
-  bool in_cxx_method_body() const { return in_cxx_method_body_; }
+  bool in_cxx_method_body() const { return (use_flags_ & UF_InCxxMethodBody); }
   const string& comment() const { return comment_; }
   bool ignore_use() const { return ignore_use_; }
   bool is_iwyu_violation() const { return is_iwyu_violation_; }
@@ -106,7 +107,7 @@ class OneUse {
   string decl_filepath_;           // filepath where the symbol lives
   clang::SourceLocation use_loc_;  // where the symbol is used from
   UseKind use_kind_;               // kFullUse or kForwardDeclareUse
-  bool in_cxx_method_body_;        // true if use is inside a C++ method body
+  UseFlags use_flags_;             // flags describing features of the use
   string comment_;                 // If not empty, append to clang warning msg
   vector<string> public_headers_;  // header to #include if dfn hdr is private
   string suggested_header_;        // header that allows us to satisfy use
@@ -230,7 +231,7 @@ class IwyuFileInfo {
 
   void ReportFullSymbolUse(clang::SourceLocation use_loc,
                            const clang::NamedDecl* decl,
-                           bool in_cxx_method_body, const char* comment);
+                           UseFlags flags, const char* comment);
   // This is used for symbols with a made up dfn_filepath.  Currently it's used
   // only for placement operator new in templates (see
   // IwyuBaseAstVisitor::VisitCXXNewExpr).
@@ -250,13 +251,13 @@ class IwyuFileInfo {
   // We only allow forward-declaring of decls, not arbitrary symbols.
   void ReportForwardDeclareUse(clang::SourceLocation use_loc,
                                const clang::NamedDecl* decl,
-                               bool in_cxx_method_body, const char* comment);
+                               UseFlags flags, const char* comment);
 
   // Called whenever a NamedDecl is accessed through a UsingDecl.
   // ie: using std::swap; swap(a, b); 
   void ReportUsingDeclUse(clang::SourceLocation use_loc,
                           const clang::UsingDecl* using_decl,
-                          bool in_cxx_method_body, const char* comment);
+                          UseFlags flags, const char* comment);
 
   // This is used when we see a // NOLINT comment, for instance.  It says
   // '#include this header file as-is, without any public-header mapping.'
diff --git a/iwyu_use_flags.h b/iwyu_use_flags.h
new file mode 100644
index 0000000..45a63a2
--- /dev/null
+++ b/iwyu_use_flags.h
@@ -0,0 +1,23 @@
+//===--- iwyu_use_flags.h - describe various contextual features of uses --===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef INCLUDE_WHAT_YOU_USE_IWYU_USE_FLAGS_H_
+#define INCLUDE_WHAT_YOU_USE_IWYU_USE_FLAGS_H_
+
+namespace include_what_you_use {
+
+// Flags describing special features of a use that influence IWYU analysis.
+typedef unsigned UseFlags;
+
+const UseFlags UF_None = 0;
+const UseFlags UF_InCxxMethodBody = 1; // use is inside a C++ method body
+
+}
+
+#endif