use system libs by default

.clang-format

@@ -227,3 +227,7 @@ IncludeCategories:
 # Comments
 FixNamespaceComments: true
 CommentPragmas: '^ clang-format'
+
+---
+Language: Json
+BasedOnStyle: llvm

CMakeLists.txt

@@ -261,15 +261,6 @@ if (NOT EXISTS "${LIBCXX_DIR}")
             "Please provide a LLVM with libc++ enabled\n")
 endif()
 
-set(STDLIB_INCLUDE_DIR "${LLVM_BINARY_DIR}/lib/clang/${Clang_VERSION_MAJOR}/include"
-                       CACHE PATH "Path to the clang headers include directory")
-message(STATUS "STDLIB_INCLUDE_DIR: ${STDLIB_INCLUDE_DIR}")
-if (NOT EXISTS "${STDLIB_INCLUDE_DIR}")
-    message(FATAL_ERROR
-            "STDLIB_INCLUDE_DIR (${STDLIB_INCLUDE_DIR}) does not exist.\n"
-            "Missing clang headers\n")
-endif()
-
 list(APPEND CMAKE_MODULE_PATH "${LLVM_CMAKE_DIR}")
 include(HandleLLVMOptions)
 add_definitions(${LLVM_DEFINITIONS})
@@ -388,6 +379,7 @@ if (WIN32)
             mrdocs-core
             PUBLIC
             /permissive-    # strict C++
+            /Zc:__cplusplus # report C++ standard support
             /W4             # enable all warnings
             /MP             # multi-processor compilation
             /EHs            # C++ Exception handling
@@ -411,6 +403,13 @@ if (MRDOCS_DOCUMENTATION_BUILD)
     return()
 endif()
 
+# Replicate the clang resource directory structure within our own build,
+# so that libclang will find it when executing directly from the build directory.
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "bin")
+file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/lib/clang")
+set(RESOURCE_DIR "lib/clang/${Clang_VERSION_MAJOR}")
+file(CREATE_LINK "${LLVM_BINARY_DIR}/${RESOURCE_DIR}" "${CMAKE_CURRENT_BINARY_DIR}/${RESOURCE_DIR}" SYMBOLIC)
+
 #-------------------------------------------------
 #
 # Tool
@@ -490,7 +489,6 @@ if (MRDOCS_BUILD_TESTS)
                 "--addons=${CMAKE_SOURCE_DIR}/share/mrdocs/addons"
                 --generator=${testgenerator}
                 "--stdlib-includes=${LIBCXX_DIR}"
-                "--stdlib-includes=${STDLIB_INCLUDE_DIR}"
                 "--libc-includes=${CMAKE_SOURCE_DIR}/share/mrdocs/headers/libc-stubs"
                 --log-level=warn
         )
@@ -505,7 +503,6 @@ if (MRDOCS_BUILD_TESTS)
                     "--addons=${CMAKE_SOURCE_DIR}/share/mrdocs/addons"
                     --generator=${testgenerator}
                     "--stdlib-includes=${LIBCXX_DIR}"
-                    "--stdlib-includes=${STDLIB_INCLUDE_DIR}"
                     "--libc-includes=${CMAKE_SOURCE_DIR}/share/mrdocs/headers/libc-stubs"
                     --log-level=warn
                 DEPENDS mrdocs-test
@@ -703,9 +700,6 @@ if (MRDOCS_INSTALL)
     install(DIRECTORY ${LIBCXX_DIR}/
             DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/mrdocs/headers/libcxx
             FILES_MATCHING PATTERN "*")
-    install(DIRECTORY ${STDLIB_INCLUDE_DIR}/
-            DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/mrdocs/headers/clang
-            FILES_MATCHING PATTERN "*")
     install(DIRECTORY ${CMAKE_SOURCE_DIR}/share/mrdocs/headers/libc-stubs/
             DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/mrdocs/headers/libc-stubs
             FILES_MATCHING PATTERN "*")

docs/modules/ROOT/pages/usage.adoc

@@ -278,7 +278,7 @@ It's also common for libraries to depend on the C++ standard library, the C stan
 
 That means unless `-nostdinc` is defined, all systems include paths are included. This is what allows the user to also use headers like `<Windows.h>` or `<linux/version.h>` without explicitly including anything else, even though they are not part of the C standard library. This is often seen as a convenience but can lead to portability issues.
 
-In this context, MrDocs provides the `use-system-stdlib` and `use-system-libc` options. Both are set as `false` by default, meaning MrDocs will compile the code as if the `-nostdinc&plus;&plus; -nostdlib&plus;&plus;` and `-nostdinc` flags were passed to Clang. Additionally:
+In this context, MrDocs provides the `use-system-stdlib` and `use-system-libc` options. Both are set as `true` by default; setting both to `false` results in MrDocs compiling the code as if the `-nostdinc&plus;&plus; -nostdlib&plus;&plus;` and `-nostdinc` flags were passed to Clang. Additionally:
 
 - When `use-system-stdlib` is `false`, MrDocs will use the bundled libc&plus;&plus; headers available in `<mrdocs-root>/share/mrdocs/headers/libcxx` and `<mrdocs-root>/share/mrdocs/headers/clang`. These paths can be adjusted with the `stdlib-includes` option.
 - When `use-system-libc` is `false`, MrDocs will use the bundled libc stubs available in `<mrdocs-root>/share/mrdocs/headers/libc-stubs`. This path can be adjusted with the `libc-includes` option.

docs/mrdocs.schema.json

@@ -531,8 +531,7 @@
     },
     "stdlib-includes": {
       "default": [
-        "<mrdocs-root>/share/mrdocs/headers/libcxx",
-        "<mrdocs-root>/share/mrdocs/headers/clang"
+        "<mrdocs-root>/share/mrdocs/headers/libcxx"
       ],
       "description": "When `use-system-stdlib` is disabled, the C++ standard library headers are available in these paths.",
       "items": {
@@ -557,7 +556,7 @@
       "type": "string"
     },
     "use-system-libc": {
-      "default": false,
+      "default": true,
       "description": "To achieve reproducible results, MrDocs bundles the LibC headers with its definitions. To use the C standard library available in the system instead, set this option to true.",
       "enum": [
         true,
@@ -567,7 +566,7 @@
       "type": "boolean"
     },
     "use-system-stdlib": {
-      "default": false,
+      "default": true,
       "description": "To achieve reproducible results, MrDocs bundles the LibC++ headers. To use the C++ standard library available in the system instead, set this option to true.",
       "enum": [
         true,

docs/website/snippets/sqrt.cpp

@@ -1,5 +1,4 @@
 #include <type_traits>
-#include <stdexcept>
 
 /** Computes the square root of an integral value.
 

src/lib/AST/ASTVisitor.cpp

@@ -2378,7 +2378,8 @@ extractSFINAEInfo(clang::QualType const T)
     Result.Type = resultType->getAsType();
     for (std::size_t I = 0; I < Args.size(); ++I)
     {
-        if (SFINAEControl->ControllingParams[I])
+        if (I < SFINAEControl->ControllingParams.size()
+            && SFINAEControl->ControllingParams[I])
         {
             MRDOCS_SYMBOL_TRACE(Args[I], context_);
             clang::TemplateArgument ArgsI = Args[I];

src/lib/ConfigOptions.json

@@ -493,16 +493,15 @@
         "brief": "Use the system C++ standard library",
         "details": "To achieve reproducible results, MrDocs bundles the LibC++ headers. To use the C++ standard library available in the system instead, set this option to true.",
         "type": "bool",
-        "default": false
+        "default": true
       },
       {
         "name": "stdlib-includes",
         "brief": "C++ Standard Library include paths",
         "details": "When `use-system-stdlib` is disabled, the C++ standard library headers are available in these paths.",
         "type": "list<path>",
         "default": [
-          "<mrdocs-root>/share/mrdocs/headers/libcxx",
-          "<mrdocs-root>/share/mrdocs/headers/clang"
+          "<mrdocs-root>/share/mrdocs/headers/libcxx"
         ],
         "relative-to": "<config-dir>",
         "must-exist": false,
@@ -513,7 +512,7 @@
         "brief": "Use the system C standard library",
         "details": "To achieve reproducible results, MrDocs bundles the LibC headers with its definitions. To use the C standard library available in the system instead, set this option to true.",
         "type": "bool",
-        "default": false
+        "default": true
       },
       {
         "name": "libc-includes",
@@ -672,4 +671,4 @@
       }
     ]
   }
-]
+]

src/lib/MrDocsCompilationDatabase.cpp

@@ -302,7 +302,10 @@ adjustCommandLine(
         cmdLineCStrs.data(),
         cmdLineCStrs.data() + cmdLineCStrs.size());
 
-    auto const systemIncludeFlag = is_clang_cl ? "-external:I" : "-isystem";
+    char const* systemIncludeFlag = is_clang_cl ? "-external:I" : "-isystem";
+    // FIXME: No CL equivalent, but not really needed there?
+    char const* afterIncludeFlag = is_clang_cl ? "-external:I" : "-idirafter";
+
 
     // ------------------------------------------------------
     // Supress all warnings
@@ -406,10 +409,10 @@ adjustCommandLine(
 
     if (!(*config)->useSystemLibc)
     {
-        new_cmdline.emplace_back("-nostdinc");
+        new_cmdline.emplace_back(is_clang_cl ? "-X" : "-nostdlibinc");
         for (auto const& inc : (*config)->libcIncludes)
         {
-            new_cmdline.emplace_back(systemIncludeFlag);
+            new_cmdline.emplace_back(afterIncludeFlag);
             new_cmdline.emplace_back(inc);
         }
     }

src/lib/MrDocsSettingsDB.cpp

@@ -11,6 +11,7 @@
 
 #include "MrDocsSettingsDB.hpp"
 #include <mrdocs/Support/Path.hpp>
+#include <llvm/Support/Program.h>
 
 
 namespace mrdocs {
@@ -60,17 +61,18 @@ MrDocsSettingsDB::MrDocsSettingsDB(ConfigImpl const& config)
         });
     }
 
+    llvm::ErrorOr<std::string> clangPath = llvm::sys::findProgramByName(
+        "clang");
+
     for (auto const& pathName: sourceFiles)
     {
         // auto fileName = files::getFileName(pathName);
         auto parentDir = files::getParentDir(pathName);
 
         std::vector<std::string> cmds;
-        cmds.emplace_back("clang");
+        cmds.emplace_back(clangPath ? *clangPath : "clang");
         cmds.emplace_back("-fsyntax-only");
         cmds.emplace_back("-std=c++23");
-        cmds.emplace_back("-pedantic-errors");
-        cmds.emplace_back("-Werror");
         cmds.emplace_back("-x");
         cmds.emplace_back("c++");
         cmds.emplace_back(pathName);

src/test/TestRunner.cpp

@@ -125,7 +125,10 @@ handleFile(
 
     auto parentDir = files::getParentDir(filePath);
     std::unordered_map<std::string, std::vector<std::string>>
-        defaultIncludePaths;
+        defaultIncludePaths = {
+            {    "clang", { MRDOCS_TEST_FILES_DIR "/include" } },
+            { "clang-cl", { MRDOCS_TEST_FILES_DIR "/include" } },
+    };
 
     // Test normally
     {

test-files/golden-tests/config/sfinae/redeclare.cpp

@@ -10,5 +10,4 @@ void f(std::enable_if_t<std::is_class_v<T>>);
 
 template <typename T>
 void f(std::enable_if_t<std::is_class_v<T>>)
-{
-}
+{}

test-files/golden-tests/config/sfinae/redeclare.yml

@@ -0,0 +1,2 @@
+warn-if-doc-error: false
+warn-no-paramdoc: false

test-files/golden-tests/config/sfinae/return-based.yml

@@ -0,0 +1,2 @@
+warn-if-doc-error: false
+warn-no-paramdoc: false

test-files/golden-tests/core/libcxx.yml

@@ -0,0 +1,2 @@
+use-system-stdlib: false
+use-system-libc: false

test-files/golden-tests/snippets/sqrt.cpp

@@ -1,5 +1,4 @@
 #include <type_traits>
-#include <stdexcept>
 
 /** Computes the square root of an integral value.
 

test-files/golden-tests/snippets/sqrt.xml

@@ -5,7 +5,7 @@
   <template>
     <tparam name="T" class="type"/>
     <function name="sqrt" requires="std::is_integral_v&lt;T&gt;" id="Ys2WHtLDVIke+oa2xBB2ekE+xds=">
-      <file short-path="sqrt.cpp" source-path="sqrt.cpp" line="15" class="def"/>
+      <file short-path="sqrt.cpp" source-path="sqrt.cpp" line="14" class="def"/>
       <return>
         <type name="T"/>
       </return>

test-files/golden-tests/snippets/sqrt.yml

@@ -0,0 +1,2 @@
+warn-if-doc-error: false
+warn-no-paramdoc: false

test-files/golden-tests/symbols/function/sfinae.cpp

@@ -1,5 +1,4 @@
 #include <type_traits>
-#include <stdexcept>
 
 /// Enabled via return type
 template <class T>