gdb/testsuite: add macros test for source files compiled in various ways

Using different ways of passing source file paths to compilers results n
different file and directory paths in the line header.  For example:

  - gcc foo.c
  - gcc ./foo.c
  - gcc ../cwd/foo.c
  - gcc $PWD/foo.c

Because of this, GDB sometimes failed to look up macros.  The previous
patch fixed that as much as possible.  This patch adds the corresponding
tests.

Add both a DWARF assembler-based test and a regular test.  The DWARF
assembled-based one tests some hard-coded debug info based on what I
have observed some specific versions of gcc and clang generate.  We want
to make sure that GDB keeps handling all these cases correctly, even if
it's not always clear whether they are really valid DWARF.  Also, they
will be tested no matter what the current target compiler is for a given
test run.

The regular test is compiled using the target compiler, so it may help
find bugs when testing against some other toolchains than what was used
to generate the DWARF assembler-based test.

For the DWARF assembler-based test, add to testsuite/lib/dwarf.exp the
necessary code to generate a DWARF5 .debug_macro section.  The design of
the new procs is based on what was done for rnglists and loclists.

To test against a specific compiler one can use this command, for
example:

    $ make check TESTS="gdb.base/macro-source-path.exp" RUNTESTFLAGS="CC_FOR_TARGET=clang --target_board unix/gdb:debug_flags=-gdwarf-5"

Change-Id: Iab8da498e57d10cc2a3d09ea136685d9278cfcf6

gdb/testsuite/gdb.base/macro-source-path.c

@@ -0,0 +1,22 @@
+/* Copyright 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 this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#define TWO 2
+
+int
+main (void)
+{
+  return ONE + TWO;
+}

gdb/testsuite/gdb.base/macro-source-path.exp

@@ -0,0 +1,87 @@
+# This testcase is part of GDB, the GNU debugger.
+
+# Copyright 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Compile a source file using different ways of passing the path to the
+# compiler.  Then, verify that we can print a macro defined in that file.
+
+standard_testfile
+
+# If the host is remote, source files are uploaded to the host and compiled
+# there, but without the directory structure we expect, making the test
+# pointless.  Skip the test in that case.
+if { [is_remote host] } {
+    return
+}
+
+# Copy the source file at these locations in the output directory ($out):
+#
+#   $out/cwd/macro-source-path.c
+#   $out/other/macro-source-path.c
+#
+# Set the current working directory to $out/cwd, so that we can test compiling
+# using relative paths.
+
+set out_dir [standard_output_file ""]
+file mkdir $out_dir/cwd
+file mkdir $out_dir/other
+file copy -force $srcdir/$subdir/$srcfile $out_dir/cwd
+file copy -force $srcdir/$subdir/$srcfile $out_dir/other
+
+# Run one test.
+#
+# SRC is the path to the source file, to be passed to the compiler as-is.
+# NAME is the name of the test.
+
+proc test { src name } {
+    with_test_prefix $name {
+	set binfile $::out_dir/$name
+
+	if { [gdb_compile $src $binfile executable {debug macros additional_flags=-DONE=1}] != "" } {
+	    fail "could not compile"
+	    return
+	}
+
+	clean_restart $binfile
+
+	if { ![runto_main] } {
+	    return
+	}
+
+	# Print the macro that is defined on the command-line.
+	if { [test_compiler_info "clang-*"] } {
+	    # This is really a clang bug, it puts the macros defined on the command
+	    # line after the main source file, in the macro table.
+	    setup_kfail "gdb/29034" "*-*-*"
+	}
+	gdb_test "print ONE" " = 1"
+
+	# Print the macro that is defined in the main file.
+	gdb_test "print TWO" " = 2"
+    }
+}
+
+# When adding a test here, please consider adding an equivalent case to the test
+# of the same name in gdb.dwarf2.
+
+with_cwd "$out_dir/cwd" {
+    test $testfile.c filename
+    test ./$testfile.c dot-filename
+    test ../cwd/$testfile.c dot-dot-filename
+    test [file normalize $testfile.c] absolute-cwd
+    test ../other/$testfile.c dot-dot-other
+    test [file normalize ../other/$testfile.c] absolute-other
+}

gdb/testsuite/gdb.dwarf2/macro-source-path.c

@@ -0,0 +1,20 @@
+/* Copyright 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 this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+int
+main (void)
+{
+  asm ("main_label: .globl main_label");
+}