[gcc/devel/rust/master] macros: add compile_error! macro

[gcc/devel/rust/master] macros: add compile_error! macro

[Thomas Schwinge]

https://gcc.gnu.org/g:35570ae4104086a20069f967fea35d7850f0710f

commit 35570ae4104086a20069f967fea35d7850f0710f
Author: liushuyu <liushuyu011@gmail.com>
Date:   Sun Apr 3 02:38:49 2022 -0600

    macros: add compile_error! macro
    
    addresses #927
    
    Signed-off-by: Zixing Liu <liushuyu011@gmail.com>

Diff:
---
 gcc/rust/expand/rust-macro-builtins.cc                   | 16 ++++++++++++++++
 gcc/rust/expand/rust-macro-builtins.h                    |  3 +++
 gcc/rust/util/rust-hir-map.cc                            |  1 +
 .../rust/compile/builtin_macro_compile_error.rs          | 12 ++++++++++++
 4 files changed, 32 insertions(+)

diff --git a/gcc/rust/expand/rust-macro-builtins.cc b/gcc/rust/expand/rust-macro-builtins.cc
index f9b8e302d09..3cd6e43d160 100644
--- a/gcc/rust/expand/rust-macro-builtins.cc
+++ b/gcc/rust/expand/rust-macro-builtins.cc
@@ -236,4 +236,20 @@ MacroBuiltin::include_str (Location invoc_locus, AST::MacroInvocData &invoc)
   return AST::ASTFragment ({node});
 }
 
+/* Expand builtin macro compile_error!("error"), which forces a compile error
+   during the compile time. */
+AST::ASTFragment
+MacroBuiltin::compile_error (Location invoc_locus, AST::MacroInvocData &invoc)
+{
+  auto lit_expr
+    = parse_single_string_literal (invoc.get_delim_tok_tree (), invoc_locus);
+  if (lit_expr == nullptr)
+    return AST::ASTFragment::create_error ();
+
+  std::string error_string = lit_expr->as_string ();
+  rust_error_at (invoc_locus, "%s", error_string.c_str ());
+
+  return AST::ASTFragment::create_error ();
+}
+
 } // namespace Rust
diff --git a/gcc/rust/expand/rust-macro-builtins.h b/gcc/rust/expand/rust-macro-builtins.h
index 8b7c016b253..b119466ac66 100644
--- a/gcc/rust/expand/rust-macro-builtins.h
+++ b/gcc/rust/expand/rust-macro-builtins.h
@@ -77,6 +77,9 @@ public:
 
   static AST::ASTFragment include_str (Location invoc_locus,
 				       AST::MacroInvocData &invoc);
+
+  static AST::ASTFragment compile_error (Location invoc_locus,
+					 AST::MacroInvocData &invoc);
 };
 } // namespace Rust
 
diff --git a/gcc/rust/util/rust-hir-map.cc b/gcc/rust/util/rust-hir-map.cc
index 7fbdbb0fc6d..47f91751aaf 100644
--- a/gcc/rust/util/rust-hir-map.cc
+++ b/gcc/rust/util/rust-hir-map.cc
@@ -753,6 +753,7 @@ Mappings::insert_macro_def (AST::MacroRulesDefinition *macro)
       {"column", MacroBuiltin::column},
       {"include_bytes", MacroBuiltin::include_bytes},
       {"include_str", MacroBuiltin::include_str},
+      {"compile_error", MacroBuiltin::compile_error},
     };
 
   auto builtin = builtin_macros.find (macro->get_rule_name ());
diff --git a/gcc/testsuite/rust/compile/builtin_macro_compile_error.rs b/gcc/testsuite/rust/compile/builtin_macro_compile_error.rs
new file mode 100644
index 00000000000..6f9a8cefebc
--- /dev/null
+++ b/gcc/testsuite/rust/compile/builtin_macro_compile_error.rs
@@ -0,0 +1,12 @@
+macro_rules! compile_error {
+  () => {{}};
+}
+
+fn main () {
+  let message = "error message";
+  compile_error! (message); // { dg-error "argument must be a string literal" "" }
+  compile_error! (); // { dg-error "macro takes 1 argument" "" }
+  compile_error! ("a", "b"); // { dg-error "macro takes 1 argument" "" }
+  compile_error! ("expected error message"); // { dg-error "expected error message" }
+  compile_error! ("expected error message",); // { dg-error "expected error message" }
+}