[gcc r12-8308] c++, coroutines: Make sure our temporaries are in a bind expr [PR105287]

[gcc r12-8308] c++, coroutines: Make sure our temporaries are in a bind expr [PR105287]

[Iain D Sandoe]

https://gcc.gnu.org/g:15a176a833f23e64ad38690a678bf938227ce46f

commit r12-8308-g15a176a833f23e64ad38690a678bf938227ce46f
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Sun Apr 17 20:58:28 2022 +0100

    c++, coroutines: Make sure our temporaries are in a bind expr [PR105287]
    
    There are a few cases where we can generate a temporary that does not need
    to be added to the coroutine frame (i.e. these are genuinely ephemeral).  The
    intent was that unnamed temporaries should not be 'promoted' to coroutine
    frame entries.  However there was a thinko and these were not actually ever
    added to the bind expressions being generated for the expanded awaits.  This
    meant that they were showing in the global namspace, leading to an empty
    DECL_CONTEXT and the ICE reported.
    
    Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
    
            PR c++/105287
    
    gcc/cp/ChangeLog:
    
            * coroutines.cc (maybe_promote_temps): Ensure generated temporaries
            are added to the bind expr.
            (add_var_to_bind): Fix local var naming to use portable punctuation.
            (register_local_var_uses): Do not add synthetic names to unnamed
            temporaries.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/coroutines/pr105287.C: New test.

Diff:
---
 gcc/cp/coroutines.cc                       | 18 +++++------
 gcc/testsuite/g++.dg/coroutines/pr105287.C | 48 ++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+), 9 deletions(-)

diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc
index 64f4b4412e5..9b651b845b7 100644
--- a/gcc/cp/coroutines.cc
+++ b/gcc/cp/coroutines.cc
@@ -3110,7 +3110,7 @@ maybe_promote_temps (tree *stmt, void *d)
 	 If the initializer is a conditional expression, we need to collect
 	 and declare any promoted variables nested within it.  DTORs for such
 	 variables must be run conditionally too.  */
-      if (t->var && DECL_NAME (t->var))
+      if (t->var)
 	{
 	  tree var = t->var;
 	  DECL_CHAIN (var) = vlist;
@@ -3311,7 +3311,7 @@ add_var_to_bind (tree& bind, tree var_type,
   tree b_vars = BIND_EXPR_VARS (bind);
   /* Build a variable to hold the condition, this will be included in the
      frame as a local var.  */
-  char *nam = xasprintf ("%s.%d", nam_root, nam_vers);
+  char *nam = xasprintf ("__%s_%d", nam_root, nam_vers);
   tree newvar = build_lang_decl (VAR_DECL, get_identifier (nam), var_type);
   free (nam);
   DECL_CHAIN (newvar) = b_vars;
@@ -3956,7 +3956,7 @@ register_local_var_uses (tree *stmt, int *do_subtree, void *d)
 	     scopes with identically named locals and still be able to
 	     identify them in the coroutine frame.  */
 	  tree lvname = DECL_NAME (lvar);
-	  char *buf;
+	  char *buf = NULL;
 
 	  /* The outermost bind scope contains the artificial variables that
 	     we inject to implement the coro state machine.  We want to be able
@@ -3966,14 +3966,14 @@ register_local_var_uses (tree *stmt, int *do_subtree, void *d)
 	  else if (lvname != NULL_TREE)
 	    buf = xasprintf ("%s_%u_%u", IDENTIFIER_POINTER (lvname),
 			     lvd->nest_depth, lvd->bind_indx);
-	  else
-	    buf = xasprintf ("_D%u_%u_%u", DECL_UID (lvar), lvd->nest_depth,
-			     lvd->bind_indx);
 	  /* TODO: Figure out if we should build a local type that has any
 	     excess alignment or size from the original decl.  */
-	  local_var.field_id
-	    = coro_make_frame_entry (lvd->field_list, buf, lvtype, lvd->loc);
-	  free (buf);
+	  if (buf)
+	    {
+	      local_var.field_id = coro_make_frame_entry (lvd->field_list, buf,
+							  lvtype, lvd->loc);
+	      free (buf);
+	    }
 	  /* We don't walk any of the local var sub-trees, they won't contain
 	     any bind exprs.  */
 	}
diff --git a/gcc/testsuite/g++.dg/coroutines/pr105287.C b/gcc/testsuite/g++.dg/coroutines/pr105287.C
new file mode 100644
index 00000000000..9790945287d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/coroutines/pr105287.C
@@ -0,0 +1,48 @@
+// { dg-additional-options "-fanalyzer" }
+// { dg-excess-errors "lots of analyzer output, but no ICE" }
+namespace std {
+template <typename _Result> struct coroutine_traits : _Result {};
+template <typename = void> struct coroutine_handle {
+  operator coroutine_handle<>();
+};
+}
+struct coro1 {
+  using handle_type = std::coroutine_handle<>;
+  coro1(handle_type);
+  struct suspend_always_prt {
+    bool await_ready() noexcept;
+    void await_suspend(handle_type) noexcept;
+    void await_resume() noexcept;
+  };
+  struct promise_type {
+    std::coroutine_handle<> ch_;
+    auto get_return_object() { return ch_; }
+    auto initial_suspend() { return suspend_always_prt{}; }
+    auto final_suspend() noexcept { return suspend_always_prt{}; }
+    void unhandled_exception();
+  };
+};
+struct BoolAwaiter {
+  BoolAwaiter(bool);
+  bool await_ready();
+  void await_suspend(std::coroutine_handle<>);
+  bool await_resume();
+};
+struct IntAwaiter {
+  IntAwaiter(int);
+  bool await_ready();
+  void await_suspend(std::coroutine_handle<>);
+  int await_resume();
+};
+coro1 my_coro() {
+ int a = 1;
+ if (a == 0) {
+   int b = 5;
+   
+ }
+ {
+   int c = 10;
+ }
+ co_await BoolAwaiter(true) && co_await IntAwaiter(a); 
+ 
+ }