[COMMITTED 9/9] pru: New validation pass for minrt

[Dimitar Dimitrov <dimitar@dinux.eu>]

Add a new pru-specific pass to validate that the assumptions for the
minimal C runtime are not violated by the user program.

gcc/ChangeLog:

	* config/pru/pru-passes.cc (class pass_pru_minrt_check): New
	pass.
	(pass_pru_minrt_check::execute): New method.
	(make_pru_minrt_check): New function.
	* config/pru/pru-passes.def (INSERT_PASS_AFTER): Register the
	minrt check pass.
	* config/pru/pru-protos.h (make_pru_minrt_check): Add
	declaration.

gcc/testsuite/ChangeLog:

	* g++.target/pru/minrt-1.cc: New test.
	* g++.target/pru/minrt-2.cc: New test.
	* g++.target/pru/minrt-3.cc: New test.
	* g++.target/pru/pru.exp: New test.
	* gcc.target/pru/minrt-1.c: New test.
	* gcc.target/pru/minrt-2.c: New test.
	* gcc.target/pru/minrt-3.c: New test.

Signed-off-by: Dimitar Dimitrov <dimitar@dinux.eu>
---
 gcc/config/pru/pru-passes.cc            | 70 +++++++++++++++++++++++++
 gcc/config/pru/pru-passes.def           |  5 ++
 gcc/config/pru/pru-protos.h             |  1 +
 gcc/testsuite/g++.target/pru/minrt-1.cc | 10 ++++
 gcc/testsuite/g++.target/pru/minrt-2.cc | 10 ++++
 gcc/testsuite/g++.target/pru/minrt-3.cc |  9 ++++
 gcc/testsuite/g++.target/pru/pru.exp    | 34 ++++++++++++
 gcc/testsuite/gcc.target/pru/minrt-1.c  | 10 ++++
 gcc/testsuite/gcc.target/pru/minrt-2.c  | 10 ++++
 gcc/testsuite/gcc.target/pru/minrt-3.c  |  9 ++++
 10 files changed, 168 insertions(+)
 create mode 100644 gcc/testsuite/g++.target/pru/minrt-1.cc
 create mode 100644 gcc/testsuite/g++.target/pru/minrt-2.cc
 create mode 100644 gcc/testsuite/g++.target/pru/minrt-3.cc
 create mode 100644 gcc/testsuite/g++.target/pru/pru.exp
 create mode 100644 gcc/testsuite/gcc.target/pru/minrt-1.c
 create mode 100644 gcc/testsuite/gcc.target/pru/minrt-2.c
 create mode 100644 gcc/testsuite/gcc.target/pru/minrt-3.c

diff --git a/gcc/config/pru/pru-passes.cc b/gcc/config/pru/pru-passes.cc
index d2c6ae8737d..5e7e22df65d 100644
--- a/gcc/config/pru/pru-passes.cc
+++ b/gcc/config/pru/pru-passes.cc
@@ -214,3 +214,73 @@ make_pru_tiabi_check (gcc::context *ctxt)
 {
   return new pass_pru_tiabi_check (ctxt);
 }
+\f
+namespace {
+
+/* Scan the tree to ensure that the compiled code by GCC
+   conforms to the non-standard minimal runtime.  */
+const pass_data pass_data_pru_minrt_check =
+{
+  GIMPLE_PASS, /* type */
+  "*pru_minrt_check", /* name */
+  OPTGROUP_NONE, /* optinfo_flags */
+  TV_NONE, /* tv_id */
+  PROP_gimple_any, /* properties_required */
+  0, /* properties_provided */
+  0, /* properties_destroyed */
+  0, /* todo_flags_start */
+  0, /* todo_flags_finish */
+};
+
+/* Implementation class for the minrt compliance-check pass.  */
+class pass_pru_minrt_check : public gimple_opt_pass
+{
+public:
+  pass_pru_minrt_check (gcc::context *ctxt)
+    : gimple_opt_pass (pass_data_pru_minrt_check, ctxt)
+  {}
+
+  /* opt_pass methods: */
+  virtual unsigned int execute (function *);
+
+  virtual bool gate (function *)
+  {
+    return TARGET_MINRT;
+  }
+
+}; // class pass_pru_minrt_check
+\f
+/* Pass implementation.  */
+unsigned
+pass_pru_minrt_check::execute (function *fun)
+{
+  const_tree fntype = TREE_TYPE (fun->decl);
+
+  if (id_equal (DECL_NAME (fun->decl), "main"))
+    {
+      /* Argument list always ends with VOID_TYPE, so subtract one
+	 to get the number of function arguments.  */
+      const unsigned num_args = list_length (TYPE_ARG_TYPES (fntype)) - 1;
+
+      if (num_args != 0)
+	error_at (DECL_SOURCE_LOCATION (fun->decl), "function %<main%> "
+		  "must have no arguments when using the "
+		  "%<-minrt%> option");
+
+      /* The required CFG analysis to detect when a functions would never
+	 return is available only with -O1 and higher.  */
+      if (optimize >= 1 && !TREE_THIS_VOLATILE (fun->decl))
+	error_at (DECL_SOURCE_LOCATION (fun->decl), "function %<main%> "
+		  "must never return when using the "
+		  "%<-minrt%> option");
+    }
+  return 0;
+}
+
+} // anon namespace
+
+gimple_opt_pass *
+make_pru_minrt_check (gcc::context *ctxt)
+{
+  return new pass_pru_minrt_check (ctxt);
+}
diff --git a/gcc/config/pru/pru-passes.def b/gcc/config/pru/pru-passes.def
index cdef089bd82..3eee313ac67 100644
--- a/gcc/config/pru/pru-passes.def
+++ b/gcc/config/pru/pru-passes.def
@@ -22,3 +22,8 @@
    If GCC cannot output a conforming code, then an error is raised.  */
 
 INSERT_PASS_AFTER (pass_warn_unused_result, 1, pru_tiabi_check);
+
+/* If -minrt option is used, then this pass would validate
+   that the compiled code by GCC is compatible with the minimal
+   C runtime.  */
+INSERT_PASS_AFTER (pass_warn_function_noreturn, 1, pru_minrt_check);
diff --git a/gcc/config/pru/pru-protos.h b/gcc/config/pru/pru-protos.h
index 74426bb86ea..3baf605d915 100644
--- a/gcc/config/pru/pru-protos.h
+++ b/gcc/config/pru/pru-protos.h
@@ -73,6 +73,7 @@ extern int pru_get_ctable_base_offset (unsigned HOST_WIDE_INT caddr);
 extern int pru_symref2ioregno (rtx op);
 
 extern rtl_opt_pass *make_pru_tiabi_check (gcc::context *);
+extern rtl_opt_pass *make_pru_minrt_check (gcc::context *);
 
 #endif /* RTX_CODE */
 
diff --git a/gcc/testsuite/g++.target/pru/minrt-1.cc b/gcc/testsuite/g++.target/pru/minrt-1.cc
new file mode 100644
index 00000000000..c30ad2cbe1e
--- /dev/null
+++ b/gcc/testsuite/g++.target/pru/minrt-1.cc
@@ -0,0 +1,10 @@
+/* Test minrt checks */
+
+/* { dg-options "-O1 -minrt" } */
+
+
+int main(void)
+{
+  for (;;)
+    ;
+}
diff --git a/gcc/testsuite/g++.target/pru/minrt-2.cc b/gcc/testsuite/g++.target/pru/minrt-2.cc
new file mode 100644
index 00000000000..258385dbdba
--- /dev/null
+++ b/gcc/testsuite/g++.target/pru/minrt-2.cc
@@ -0,0 +1,10 @@
+/* Test minrt checks */
+
+/* { dg-options "-O1 -minrt" } */
+
+int main(int argc, char *argv[]) 
+/* { dg-error "function 'main' must have no arguments when using the '-minrt' option" "" { target pru-*-* } .-1 } */
+{
+  for (;;)
+    ;
+}
diff --git a/gcc/testsuite/g++.target/pru/minrt-3.cc b/gcc/testsuite/g++.target/pru/minrt-3.cc
new file mode 100644
index 00000000000..07b4e5e430a
--- /dev/null
+++ b/gcc/testsuite/g++.target/pru/minrt-3.cc
@@ -0,0 +1,9 @@
+/* Test minrt checks */
+
+/* { dg-options "-O1 -minrt" } */
+
+int main(void)
+/* { dg-error "function 'main' must never return when using the '-minrt' option" "" { target pru-*-* } .-1 } */
+{
+    return 0;
+}
diff --git a/gcc/testsuite/g++.target/pru/pru.exp b/gcc/testsuite/g++.target/pru/pru.exp
new file mode 100644
index 00000000000..c9a3ab2b076
--- /dev/null
+++ b/gcc/testsuite/g++.target/pru/pru.exp
@@ -0,0 +1,34 @@
+# Copyright (C) 2024 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.
+
+# GCC testsuite that uses the `dg.exp' driver.
+
+# Exit immediately if this isn't a pru target.
+if ![istarget pru*-*-*] then {
+  return
+}
+
+# Load support procs.
+load_lib g++-dg.exp
+
+# Initialize `dg'.
+dg-init
+
+# Main loop.
+dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/*.cc]] "" ""
+
+# All done.
+dg-finish
diff --git a/gcc/testsuite/gcc.target/pru/minrt-1.c b/gcc/testsuite/gcc.target/pru/minrt-1.c
new file mode 100644
index 00000000000..c30ad2cbe1e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/pru/minrt-1.c
@@ -0,0 +1,10 @@
+/* Test minrt checks */
+
+/* { dg-options "-O1 -minrt" } */
+
+
+int main(void)
+{
+  for (;;)
+    ;
+}
diff --git a/gcc/testsuite/gcc.target/pru/minrt-2.c b/gcc/testsuite/gcc.target/pru/minrt-2.c
new file mode 100644
index 00000000000..258385dbdba
--- /dev/null
+++ b/gcc/testsuite/gcc.target/pru/minrt-2.c
@@ -0,0 +1,10 @@
+/* Test minrt checks */
+
+/* { dg-options "-O1 -minrt" } */
+
+int main(int argc, char *argv[]) 
+/* { dg-error "function 'main' must have no arguments when using the '-minrt' option" "" { target pru-*-* } .-1 } */
+{
+  for (;;)
+    ;
+}
diff --git a/gcc/testsuite/gcc.target/pru/minrt-3.c b/gcc/testsuite/gcc.target/pru/minrt-3.c
new file mode 100644
index 00000000000..07b4e5e430a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/pru/minrt-3.c
@@ -0,0 +1,9 @@
+/* Test minrt checks */
+
+/* { dg-options "-O1 -minrt" } */
+
+int main(void)
+/* { dg-error "function 'main' must never return when using the '-minrt' option" "" { target pru-*-* } .-1 } */
+{
+    return 0;
+}
-- 
2.45.0