Fix external macro use when fast_preprocessing=false

Forget to add standard library includes...

Fixes #39.

src/libclang/preprocessor.cpp

@@ -185,6 +185,7 @@ namespace
     }
 
     // get the command that preprocess a translation unit given the macros
+    // macro_file_path == nullptr <=> don't do fast preprocessing
     std::string get_preprocess_command(const libclang_compile_config& c, const char* full_path,
                                        const char* macro_file_path)
     {
@@ -192,11 +193,16 @@ namespace
         // -E: print preprocessor output
         // -CC: keep comments, even in macro
         // -dD: keep macros
-        // -no*: disable default include search paths
+        auto flags = std::string("-x c++ -E -CC -dD");
-        auto flags = std::string("-x c++ -E -CC -dD -nostdinc -nostdinc++");
+
+        if (macro_file_path)
+            // -no*: disable default include search paths
+            flags += " -nostdinc -nostdinc++";
+
         if (detail::libclang_compile_config_access::clang_version(c) >= 40000)
             // -Xclang -dI: print include directives as well (clang >= 4.0.0)
             flags += " -Xclang -dI";
+
         flags += diagnostics_flags();
 
         if (macro_file_path)
@@ -209,13 +215,14 @@ namespace
         std::string cmd(detail::libclang_compile_config_access::clang_binary(c) + " "
                         + std::move(flags) + " ");
 
-        // other flags, as long as they don't add include directories (if we're doing the single file optimization)
+        // other flags
         for (const auto& flag : detail::libclang_compile_config_access::flags(c))
         {
             DEBUG_ASSERT(flag.size() > 2u && flag[0] == '-', detail::assert_handler{},
                          "that's an odd flag");
-            if (macro_file_path && (flag[0] != '-' || flag[1] != 'I'))
+            if (!macro_file_path || flag[1] != 'I')
             {
+                // only add this flag if it is not an include or we're not doing fast preprocessing
                 cmd += flag;
                 cmd += ' ';
             }
@@ -431,6 +438,10 @@ namespace
     clang_preprocess_result clang_preprocess(const libclang_compile_config& c,
                                              const char* full_path, const diagnostic_logger& logger)
     {
+        // if we're fast preprocessing we only preprocess the main file, not includes
+        // this is done by disabling all include search paths when doing the preprocessing
+        // to allow macros a separate preprocessing with the -dM flag is done that extracts all macros
+        // they are then manually defined before
         auto fast_preprocessing = detail::libclang_compile_config_access::fast_preprocessing(c);
 
         auto macro_file = fast_preprocessing ? write_macro_file(c, full_path, logger) : "";
@@ -706,7 +717,7 @@ namespace
         if (starts_with(p, "*/"))
             // empty comment
             p.skip(2u);
-        else if (starts_with(p, "*") || starts_with(p, "!"))
+        else if (p.write_enabled() && (starts_with(p, "*") || starts_with(p, "!")))
         {
             // doc comment
             p.skip();
@@ -771,14 +782,14 @@ namespace
             return false;
         p.skip(2u);
 
-        if (starts_with(p, "/") || starts_with(p, "!"))
+        if (p.write_enabled() && (starts_with(p, "/") || starts_with(p, "!")))
         {
             // C++ style doc comment
             p.skip();
             auto comment = parse_cpp_doc_comment(p, false);
             merge_or_add(output, std::move(comment));
         }
-        else if (starts_with(p, "<"))
+        else if (p.write_enabled() && starts_with(p, "<"))
         {
             // end of line doc comment
             p.skip();
@@ -903,6 +914,9 @@ namespace
         DEBUG_ASSERT(starts_with(p, "\n"), detail::assert_handler{});
         // don't skip newline
 
+        if (!p.write_enabled())
+            return type_safe::nullopt;
+
         if (filename.size() > 2u && filename[0] == '.'
             && (filename[1] == '/' || filename[1] == '\\'))
             filename = filename.substr(2);
@@ -1083,7 +1097,10 @@ detail::preprocessor_output detail::preprocess(const libclang_compile_config& co
             else if (lm.value().flag == linemarker::enter_old)
             {
                 if (lm.value().file == path)
+                {
                     p.enable_write();
+                    p.set_line(lm.value().line);
+                }
             }
             else if (lm.value().flag == linemarker::line_directive && p.write_enabled())
             {

test/cpp_preprocessor.cpp

@@ -136,185 +136,3 @@ b
     });
     REQUIRE(count == 1u);
 }
-
-TEST_CASE("preprocessor line numbers")
-{
-    auto code = R"(/// 1
-
-#include <iostream>
-
-/// 5
-
-#include <string>
-
-int var;
-
-/// 11
-
-#define foo \
-    \
-    \
-    int \
-    main()
-
-/// 19
-
-foo {}
-
-/// 23
-
-/* C comment
-spanning
-multiple
-lines
-*/
-
-/**
-
-*/
-
-#include <vector>
-
-/// 37
-)";
-
-    auto file = parse({}, "preprocessor_line_numbers.cpp", code);
-    for (auto& comment : file->unmatched_comments())
-    {
-        if (comment.content[0] != '\n')
-            REQUIRE(comment.line == std::stoi(comment.content));
-    }
-    REQUIRE((file->unmatched_comments().size() == 6u + 1u));
-}
-
-TEST_CASE("comment content")
-{
-    auto code = R"(
-/// simple comment
-
-///no space
-
-/// multi
-/// line
-/// comment
-
-/** C comment */
-/**C comment no space*/
-
-/** Multiline
-C
-  comment
-with indent */
-
-    /** Multiline
-        C
-         comment
-          with
-           indent */
-
-    /** Multiline
-            * C
-            * comment
-            * with
-            * indent
-            * star */
-)";
-
-    auto file     = parse({}, "comment-content.cpp", code);
-    auto comments = file->unmatched_comments();
-    REQUIRE((comments.size() == 8u));
-
-    REQUIRE(comments[0u].content == "simple comment");
-    REQUIRE(comments[1u].content == "no space");
-    REQUIRE(comments[2u].content == "multi\nline\ncomment");
-    REQUIRE(comments[3u].content == "C comment");
-    REQUIRE(comments[4u].content == "C comment no space");
-    REQUIRE(comments[5u].content == "Multiline\nC\n  comment\nwith indent");
-    REQUIRE(comments[6u].content == "Multiline\nC\n comment\n  with\n   indent");
-    REQUIRE(comments[7u].content == "Multiline\nC\ncomment\nwith\nindent\nstar");
-}
-
-TEST_CASE("comment matching")
-{
-    auto code = R"(
-/// u
-
-/// a
-/// a
-struct a {};
-
-/// u
-/** b
-  * b */
-void b(int, float)
-{
-    auto c = '#';
-}
-
-/** u */
-//! c
-/// c
-enum class c
-{
-    d, //< d
-    /// d
-    e, //< e
-    /// e
-
-    /** f
-f **/
-    f,
-};
-
-/// g
-/// g
-#define g(name) \
-class name \
-{ \
-};
-
-/// h
-/// h
-g(h)
-
-/*! i
- i */
-using i = int;
-
-/// cstddef
-/// cstddef
-#include <cstddef>
-
-/// j
-/// j
-template <typename T/**/>
-void j();
-)";
-
-    auto file = parse({}, "comment-matching.cpp", code);
-    visit(*file, [&](const cpp_entity& e, visitor_info) {
-        if (e.kind() == cpp_entity_kind::file_t)
-            return true;
-        else if (e.name().empty())
-            return true;
-        else if (is_templated(e))
-            return true;
-
-        INFO(e.name());
-        REQUIRE(e.comment());
-        REQUIRE(e.comment().value() == e.name() + "\n" + e.name());
-        return true;
-    });
-
-    auto add = 0u;
-    for (auto& comment : file->unmatched_comments())
-    {
-        if (comment.content == "cstddef\ncstddef")
-            // happens if include parsing is not supported
-            // error is still going to be detected because if it is supported, the entity will be matched above
-            add = 1u;
-        else
-            REQUIRE(comment.content == "u");
-    }
-    REQUIRE((file->unmatched_comments().size() == 3u + add));
-}

test/preprocessor.cpp

@@ -4,9 +4,11 @@
 #include "libclang/preprocessor.hpp"
 #include "test_parser.hpp"
 
+#include <cppast/cpp_variable.hpp>
+
 using namespace cppast;
 
-TEST_CASE("preprocessor_parses_escaped_character", "[!hide][clang4]")
+TEST_CASE("preprocessor escaped character", "[!hide][clang4]")
 {
     write_file("ppec.hpp", R"(
 )");
@@ -33,9 +35,25 @@ TEST_CASE("preprocessor_parses_escaped_character", "[!hide][clang4]")
     REQUIRE(preprocessed.includes[0].file_name == "ppec.hpp");
 }
 
+TEST_CASE("preprocessing use external macro")
+{
+    auto file = parse({}, "preprocessing_external_macro.cpp", R"(
+#include <cmath>
+#ifdef _GLIBCXX_RELEASE
+
+// this requires libstdc++
+/// auto result=(__builtin_nanf(""));
+auto result = NAN;
+
+#endif
+)");
+
+    test_visit<cpp_variable>(*file, [&](const cpp_variable&) {});
+}
+
 TEST_CASE("fast_preprocessing include guard")
 {
-    auto file_name = "fast_preprocessing_include_guard";
+    auto file_name = "fast_preprocessing_include_guard.hpp";
     write_file(file_name, R"(
 // This is a C++ comment that should get skipped.
 
@@ -63,3 +81,185 @@ struct foo {};
     REQUIRE(result.macros.size() == 1u);
     REQUIRE(result.macros[0].macro->name() == "INCLUDE_GUARD");
 }
+
+TEST_CASE("preprocessor line numbers")
+{
+    auto code = R"(/// 1
+
+#include <iostream>
+
+/// 5
+
+#include <string>
+
+int var;
+
+/// 11
+
+#define foo \
+    \
+    \
+    int \
+    main()
+
+/// 19
+
+foo {}
+
+/// 23
+
+/* C comment
+spanning
+multiple
+lines
+*/
+
+/**
+
+*/
+
+#include <vector>
+
+/// 37
+)";
+
+    auto file = parse({}, "preprocessor_line_numbers.cpp", code);
+    for (auto& comment : file->unmatched_comments())
+    {
+        if (comment.content[0] != '\n')
+            REQUIRE(comment.line == std::stoi(comment.content));
+    }
+    REQUIRE((file->unmatched_comments().size() == 6u + 1u));
+}
+
+TEST_CASE("comment content")
+{
+    auto code = R"(
+/// simple comment
+
+///no space
+
+/// multi
+/// line
+/// comment
+
+/** C comment */
+/**C comment no space*/
+
+/** Multiline
+C
+  comment
+with indent */
+
+    /** Multiline
+        C
+         comment
+          with
+           indent */
+
+    /** Multiline
+            * C
+            * comment
+            * with
+            * indent
+            * star */
+)";
+
+    auto file     = parse({}, "comment-content.cpp", code);
+    auto comments = file->unmatched_comments();
+    REQUIRE((comments.size() == 8u));
+
+    REQUIRE(comments[0u].content == "simple comment");
+    REQUIRE(comments[1u].content == "no space");
+    REQUIRE(comments[2u].content == "multi\nline\ncomment");
+    REQUIRE(comments[3u].content == "C comment");
+    REQUIRE(comments[4u].content == "C comment no space");
+    REQUIRE(comments[5u].content == "Multiline\nC\n  comment\nwith indent");
+    REQUIRE(comments[6u].content == "Multiline\nC\n comment\n  with\n   indent");
+    REQUIRE(comments[7u].content == "Multiline\nC\ncomment\nwith\nindent\nstar");
+}
+
+TEST_CASE("comment matching")
+{
+    auto code = R"(
+/// u
+
+/// a
+/// a
+struct a {};
+
+/// u
+/** b
+  * b */
+void b(int, float)
+{
+    auto c = '#';
+}
+
+/** u */
+//! c
+/// c
+enum class c
+{
+    d, //< d
+    /// d
+    e, //< e
+    /// e
+
+    /** f
+f **/
+    f,
+};
+
+/// g
+/// g
+#define g(name) \
+class name \
+{ \
+};
+
+/// h
+/// h
+g(h)
+
+/*! i
+ i */
+using i = int;
+
+/// cstddef
+/// cstddef
+#include <cstddef>
+
+/// j
+/// j
+template <typename T/**/>
+void j();
+)";
+
+    auto file = parse({}, "comment-matching.cpp", code);
+    visit(*file, [&](const cpp_entity& e, visitor_info) {
+        if (e.kind() == cpp_entity_kind::file_t)
+            return true;
+        else if (e.name().empty())
+            return true;
+        else if (is_templated(e))
+            return true;
+
+        INFO(e.name());
+        REQUIRE(e.comment());
+        REQUIRE(e.comment().value() == e.name() + "\n" + e.name());
+        return true;
+    });
+
+    auto add = 0u;
+    for (auto& comment : file->unmatched_comments())
+    {
+        if (comment.content == "cstddef\ncstddef")
+            // happens if include parsing is not supported
+            // error is still going to be detected because if it is supported, the entity will be matched above
+            add = 1u;
+        else
+            REQUIRE(comment.content == "u");
+    }
+    REQUIRE((file->unmatched_comments().size() == 3u + add));
+}