Better symbol resolution (ie, goto definition) for macro arguments.

src/clang_utils.cc

@@ -39,6 +39,7 @@ optional<lsDiagnostic> BuildAndDisposeDiagnostic(CXDiagnostic diagnostic) {
 
   lsDiagnostic ls_diagnostic;
 
+  // TODO: consider using clang_getDiagnosticRange
   // TODO: ls_diagnostic.range is lsRange, we have Range. We should only be
   // storing Range types when inside the indexer so that index <-> buffer
   // remapping logic is applied.

src/lex_utils.cc

@@ -2,17 +2,22 @@
 
 #include <doctest/doctest.h>
 
+#include <algorithm>
+
 int GetOffsetForPosition(lsPosition position, const std::string& content) {
+  if (content.empty())
+    return 0;
+
   int offset = 0;
 
   int remaining_lines = position.line;
-  while (remaining_lines > 0) {
+  while (remaining_lines > 0 && offset < content.size()) {
     if (content[offset] == '\n')
       --remaining_lines;
     ++offset;
   }
 
-  return offset + position.character;
+  return std::min<int>(offset + position.character, content.size() - 1);
 }
 
 lsPosition CharPos(const std::string& search, char character, int character_offset) {
@@ -204,6 +209,16 @@ bool SubstringMatch(const std::string& search, const std::string& content) {
   return false;
 }
 
+TEST_SUITE("Offset");
+
+TEST_CASE("over range") {
+  std::string content = "foo";
+  int offset = GetOffsetForPosition(lsPosition(10, 10), content);
+  REQUIRE(offset < content.size());
+}
+
+TEST_SUITE_END();
+
 TEST_SUITE("Substring");
 
 TEST_CASE("match") {

src/query_utils.cc

@@ -1,5 +1,16 @@
 #include "query_utils.h"
 
+namespace {
+
+// Computes roughly how long |range| is.
+int ComputeRangeSize(const Range& range) {
+  if (range.start.line != range.end.line)
+    return INT_MAX;
+  return range.end.column - range.start.column;
+}
+
+}  // namespace
+
 optional<QueryLocation> GetDefinitionSpellingOfSymbol(QueryDatabase* db, const QueryTypeId& id) {
   optional<QueryType>& type = db->types[id.id];
   if (type)
@@ -550,12 +561,20 @@ std::vector<SymbolRef> FindSymbolsAtLocation(WorkingFile* working_file, QueryFil
       symbols.push_back(ref);
   }
 
-  // Order function symbols first. This makes goto definition work better when
-  // used on a constructor.
+  // Order shorter ranges first, since they are more detailed/precise. This is
+  // important for macros which generate code so that we can resolving the
+  // macro argument takes priority over the entire macro body.
+  //
+  // Order functions before other types, which makes goto definition work
+  // better on constructors.
   std::sort(symbols.begin(), symbols.end(), [](const SymbolRef& a, const SymbolRef& b) {
-    if (a.idx.kind != b.idx.kind && a.idx.kind == SymbolKind::Func)
-      return 1;
-    return 0;
+    int a_size = ComputeRangeSize(a.loc.range);
+    int b_size = ComputeRangeSize(b.loc.range);
+
+    if (a_size == b_size)
+      return a.idx.kind != b.idx.kind && a.idx.kind == SymbolKind::Func;
+
+    return a_size < b_size;
   });
 
   return symbols;

src/working_files.cc

@@ -404,6 +404,7 @@ TEST_CASE("auto-insert )") {
 }
 
 TEST_CASE("existing completion") {
+  // TODO: remove trailing space in zz.asdf. Lexing doesn't work correctly if done at the end of input.
   WorkingFile f("foo.cc", "zzz.asdf ");
   bool is_global_completion;
   std::string existing_completion;

tests/macros/complex.cc

@@ -0,0 +1,59 @@
+#define FOO(aaa, bbb) \
+  int a();\
+  int a() { return aaa + bbb; }
+
+
+int make1() {
+  return 3;
+}
+const int make2 = 5;
+
+
+FOO(make1(), make2);
+
+/*
+OUTPUT:
+{
+  "funcs": [{
+      "id": 0,
+      "usr": "c:@F@make1#",
+      "short_name": "make1",
+      "detailed_name": "int make1()",
+      "definition_spelling": "6:5-6:10",
+      "definition_extent": "6:1-8:2",
+      "callers": ["1@12:5-12:10"]
+    }, {
+      "id": 1,
+      "usr": "c:@F@a#",
+      "short_name": "a",
+      "detailed_name": "int a()",
+      "declarations": [{
+          "spelling": "12:1-12:20",
+          "extent": "12:1-12:20",
+          "content": "int a();\n   int a() { return aaa + bbb; }\n\n\n int make1() {\n   return 3;\n }\n const int make2 = 5;\n\n\n FOO(make1(), make2)"
+        }],
+      "definition_spelling": "12:1-12:20",
+      "definition_extent": "12:1-12:20",
+      "callees": ["0@12:5-12:10"]
+    }],
+  "vars": [{
+      "id": 0,
+      "usr": "c:complex.cc@make2",
+      "short_name": "make2",
+      "detailed_name": "const int make2",
+      "definition_spelling": "9:11-9:16",
+      "definition_extent": "9:1-9:20",
+      "is_local": false,
+      "uses": ["9:11-9:16", "12:14-12:19"]
+    }, {
+      "id": 1,
+      "usr": "c:complex.cc@8@macro@FOO",
+      "short_name": "FOO",
+      "detailed_name": "FOO",
+      "definition_spelling": "1:9-1:12",
+      "definition_extent": "1:9-3:32",
+      "is_local": false,
+      "uses": ["1:9-1:12", "12:1-12:4"]
+    }]
+}
+*/