rust: Add -frust-compile-until option

This option helps ensure that we do not introduce regressions on various
parts of the compilation pipeline. For example, a testcase (or testsuite
from the `testing` project) might pass attribute checking, expansion and
lowering, but fail during typechecking. Should a change suddenly make
that testcase fail expansion, we would not be able to notice it. By
generating tests that run up until expansion, typechecking, compilation
and so forth we ensure that no regressions are added accidentally to
already failing tests/testsuites.

1 files changed, 24 insertions, 1 deletions

diff --git a/gcc/rust/rust-session-manager.h b/gcc/rust/rust-session-manager.h
index b3724c5..6ecd513 100644
--- a/gcc/rust/rust-session-manager.h
+++ b/gcc/rust/rust-session-manager.h
@@ -199,6 +199,22 @@ struct CompileOptions
   } edition
     = Edition::E2015;
 
+  enum class CompileStep
+  {
+    Ast,
+    AttributeCheck,
+    Expansion,
+    NameResolution,
+    Lowering,
+    TypeCheck,
+    Privacy,
+    Unsafety,
+    Const,
+    Compilation,
+    End,
+  } compile_until
+    = CompileStep::End;
+
   bool dump_option_enabled (DumpOption option) const
   {
     return dump_options.find (option) != dump_options.end ();
@@ -239,7 +255,14 @@ struct CompileOptions
     edition = static_cast<Edition> (raw_edition);
   }
 
-  const Edition &get_edition () { return edition; }
+  const Edition &get_edition () const { return edition; }
+
+  void set_compile_step (int raw_step)
+  {
+    compile_until = static_cast<CompileStep> (raw_step);
+  }
+
+  const CompileStep &get_compile_until () const { return compile_until; }
 
   void set_metadata_output (const std::string &path)
   {