gccrs: Add Debug info testsuite

This testsuite is specifically about testcases which scan the asm debug
info for results.

	gcc/testsuite/
	* rust/debug/chartype.rs: New.
	* rust/debug/custom_link_section.rs: New.
	* rust/debug/debug.exp: New.
	* rust/debug/i8u8.rs: New.
	* rust/debug/lang.rs: New.
	* rust/debug/no_mangle.rs: New.
	* rust/debug/oldlang.rs: New.
	* rust/debug/tuple.rs: New.
	* rust/debug/win64-abi.rs: New.

Co-authored-by: Tom Tromey <tom@tromey.com>
Co-authored-by: Mark Wielaard <mark@klomp.org>
Co-authored-by: Marc Poulhiès <dkm@kataplop.net>

gcc/testsuite/rust/debug/chartype.rs

@@ -0,0 +1,10 @@
+// 'char' should use DW_ATE_UTF
+fn main () {
+    let c = 'x';
+// { dg-do compile }
+// Use -w to avoid warnings about the unused variables
+// DW_ATE_UTF entered in DWARF 4.
+// { dg-options "-w -gdwarf-4 -dA" }
+// DW_ATE_UTF = 0x10
+// { dg-final { scan-assembler "0x10\[ \t]\[^\n\r]* DW_AT_encoding" } } */
+}

gcc/testsuite/rust/debug/custom_link_section.rs

@@ -0,0 +1,13 @@
+#[link_section = ".universe"]
+fn not_in_text() -> i32 {
+    42
+}
+
+fn main() -> i32 {
+// { dg-do compile }
+// { dg-options "-gdwarf-5 -dA -w" }
+    not_in_text();
+// { dg-final { scan-assembler ".universe" } } */
+
+    0
+}

gcc/testsuite/rust/debug/debug.exp

@@ -0,0 +1,33 @@
+# Copyright (C) 2021-2022 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/>.
+
+# Debugging tests.
+
+# Load support procs.
+load_lib rust-dg.exp
+
+# Initialize `dg'.
+dg-init
+
+# Main loop.
+set saved-dg-do-what-default ${dg-do-what-default}
+
+set dg-do-what-default "compile"
+dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/*.rs]] "" ""
+set dg-do-what-default ${saved-dg-do-what-default}
+
+# All done.
+dg-finish

gcc/testsuite/rust/debug/i8u8.rs

@@ -0,0 +1,12 @@
+// i8 and u8 types should not have the DWARF 'char' encoding.
+fn main () {
+    let x : i8 = 5;
+    let y : u8 = 7;
+// { dg-do compile }
+// Use -w to avoid warnings about the unused variables
+// { dg-options "-w -g -dA" }
+// DW_ATE_signed_char = 6
+// { dg-final { scan-assembler-not "0x6\[ \t]\[^\n\r]* DW_AT_encoding" } } */
+// DW_ATE_unsigned_char = 8
+// { dg-final { scan-assembler-not "0x8\[ \t]\[^\n\r]* DW_AT_encoding" } } */
+}

gcc/testsuite/rust/debug/lang.rs

@@ -0,0 +1,6 @@
+fn main () {
+// { dg-do compile }
+// { dg-options "-gdwarf-5 -dA" }
+// DW_LANG_Rust is 0x1c
+// { dg-final { scan-assembler "0x1c\[ \t]\[^\n\r]* DW_AT_language" } } */
+}

gcc/testsuite/rust/debug/no_mangle.rs

@@ -0,0 +1,17 @@
+#[no_mangle]
+fn do_not_mangle() -> i32 {
+    0 
+}
+
+fn please_mangle() {}
+
+fn main() {
+// { dg-do compile }
+// { dg-options "-gdwarf-5 -dA" }
+    let _ = do_not_mangle();
+    please_mangle();
+// look for unmangled function name:
+// { dg-final { scan-assembler "do_not_mangle:" } } */
+// look for legacy mangled function name:
+// { dg-final { scan-assembler "13please_mangle" } } */
+}

gcc/testsuite/rust/debug/oldlang.rs

@@ -0,0 +1,6 @@
+fn main () {
+// { dg-do compile }
+// { dg-options "-gstrict-dwarf -gdwarf-3 -dA" }
+// Strict DWARF < 5 uses DW_LANG_C = 0x0002
+// { dg-final { scan-assembler "0x2\[ \t]\[^\n\r]* DW_AT_language" } } */
+}

gcc/testsuite/rust/debug/tuple.rs

@@ -0,0 +1,8 @@
+fn main () {
+// { dg-do compile }
+// { dg-options "-gdwarf-5 -dA -w" }
+    let x = (32, 32);
+// Look for field __0 and __1
+// { dg-final { scan-assembler "__0" } } */
+// { dg-final { scan-assembler "__1" } } */
+}

gcc/testsuite/rust/debug/win64-abi.rs

@@ -0,0 +1,11 @@
+// { dg-do compile { target { x86_64-*-* } } }
+// { dg-options "-gdwarf-5 -dA -w -O1 -m64" }
+pub extern "win64" fn square(num: i32) -> i32 {
+    num * num
+}
+
+fn main() {
+    // MS ABI dictates that the first argument is ecx instead of edi from the sysv world
+    // { dg-final { scan-assembler "%ecx, %ecx" } }
+    square(1);
+}