[clang][cli] Specify KeyPath prefixes via TableGen classes

It turns out we need to handle `LangOptions` separately from the rest of the options. `LangOptions` used to be conditionally parsed only when `!(DashX.getFormat() == InputKind::Precompiled || DashX.getLanguage() == Language::LLVM_IR)` and we need to restore this order (for more info, see D94682).

We could do this similarly to how `DiagnosticOptions` are handled: via a counterpart to the `IsDiag` mix-in (e.g. `IsLang`). These mix-ins would prefix the option key path with the appropriate `CompilerInvocation::XxxOpts` member. However, this solution would be problematic, as we'd now have two kinds of options (`Lang` and `Diag`) with seemingly incomplete key paths in the same file. To understand what `CompilerInvocation` member an option affects, one would need to read the whole option definition and notice the `IsDiag` or `IsLang` class.

Instead, this patch introduces more robust way to handle different kinds of options separately: via the `KeyPathAndMacroPrefix` class. We have one specialization of that class per `CompilerInvocation` member (e.g. `LangOpts`, `DiagnosticOpts`, etc.). Now, instead of specifying a key path with `"LangOpts->UndefPrefixes"`, we use `LangOpts<"UndefPrefixes">`. This keeps the readability intact (you don't have to look for the `IsLang` mix-in, the key path is complete on its own) and allows us to specify a custom macro prefix within `LangOpts`.

Reviewed By: Bigcheese

Differential Revision: https://reviews.llvm.org/D94676

1 files changed, 5 insertions, 10 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 6d5b4a8..37d7f6f 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1404,6 +1404,9 @@ bool clang::ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
     Diags = &*IgnoringDiags;
   }
 
+  // The key paths of diagnostic options defined in Options.td start with
+  // "DiagnosticOpts->". Let's provide the expected variable name and type.
+  DiagnosticOptions *DiagnosticOpts = &Opts;
   bool Success = true;
 
 #define DIAG_OPTION_WITH_MARSHALLING(                                          \
@@ -1412,7 +1415,7 @@ bool clang::ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
     DEFAULT_VALUE, IMPLIED_CHECK, IMPLIED_VALUE, NORMALIZER, DENORMALIZER,     \
     MERGER, EXTRACTOR, TABLE_INDEX)                                            \
   PARSE_OPTION_WITH_MARSHALLING(Args, *Diags, Success, ID, FLAGS, PARAM,       \
-                                SHOULD_PARSE, Opts.KEYPATH, DEFAULT_VALUE,     \
+                                SHOULD_PARSE, KEYPATH, DEFAULT_VALUE,          \
                                 IMPLIED_CHECK, IMPLIED_VALUE, NORMALIZER,      \
                                 MERGER, TABLE_INDEX)
 #include "clang/Driver/Options.inc"
@@ -3153,15 +3156,7 @@ void CompilerInvocation::generateCC1CommandLine(
                                    IMPLIED_CHECK, IMPLIED_VALUE, DENORMALIZER, \
                                    EXTRACTOR, TABLE_INDEX)
 
-#define DIAG_OPTION_WITH_MARSHALLING(                                          \
-    PREFIX_TYPE, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,        \
-    HELPTEXT, METAVAR, VALUES, SPELLING, SHOULD_PARSE, ALWAYS_EMIT, KEYPATH,   \
-    DEFAULT_VALUE, IMPLIED_CHECK, IMPLIED_VALUE, NORMALIZER, DENORMALIZER,     \
-    MERGER, EXTRACTOR, TABLE_INDEX)                                            \
-  GENERATE_OPTION_WITH_MARSHALLING(                                            \
-      Args, SA, KIND, FLAGS, SPELLING, ALWAYS_EMIT,                            \
-      this->DiagnosticOpts->KEYPATH, DEFAULT_VALUE, IMPLIED_CHECK,             \
-      IMPLIED_VALUE, DENORMALIZER, EXTRACTOR, TABLE_INDEX)
+#define DIAG_OPTION_WITH_MARSHALLING OPTION_WITH_MARSHALLING
 
 #include "clang/Driver/Options.inc"