Support for __LINE__ and __FILE__ in preprocessor (#1772)

* #include an absolute path didn't work - because paths were taken to always be relative.

* First pass support for __LINE__ and __FILE__.

* Test include handling with __FILE__
Fix diagnostic compare when input is empty.

* Fix some issues in preprocessor handling of special macros like __LINE__
Add a more complex test.

* Use CONCAT2 in tests, because preprocessor doesn't quite get parameter expansion correct.

* Make __FILE__ and __LINE__ behave more like Clang/Gcc.

* A test for preprocessor bug.

* Fix __LINE__ and __FILE__ in macro expansion, should be initiating location.

* Fix some comments.

* Small tidy up around builtin macros.

* Small improvements for macro type names.
Escape found paths.

1 files changed, 19 insertions, 0 deletions

diff --git a/tools/slang-test/parse-diagnostic-util.cpp b/tools/slang-test/parse-diagnostic-util.cpp
index 41dae07f7..db16d0c7e 100644
--- a/tools/slang-test/parse-diagnostic-util.cpp
+++ b/tools/slang-test/parse-diagnostic-util.cpp
@@ -384,8 +384,27 @@ static SlangResult _findDownstreamCompiler(const UnownedStringSlice& slice, Slan
     return nullptr;
 }
 
+static bool _isWhitespace(const UnownedStringSlice& slice)
+{
+    for (const char c : slice)
+    {
+        if (!CharUtil::isWhitespace(c))
+        {
+            return false;
+        }
+    }
+    return true;
+}
+
 /* static */SlangResult ParseDiagnosticUtil::parseDiagnostics(const UnownedStringSlice& inText, List<DownstreamDiagnostic>& outDiagnostics)
 {
+    if (_isWhitespace(inText))
+    {
+        // If it's empty, then there are no diagnostics to add.
+        outDiagnostics.clear();
+        return SLANG_OK;
+    }
+
     // TODO(JS):
     // As it stands output of downstream compilers isn't standardized. This can be improved upon - and if so
     // we should have a function that will parse the standardized output