[binutils-gdb] gdb/testsuite/lib/future.exp: follow dejagnu default_target_compile

[Lancelot SIX <lsix@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=5d19bc378597f880ef8a168a831be886da45e8c5

commit 5d19bc378597f880ef8a168a831be886da45e8c5
Author: Lancelot SIX <lancelot.six@amd.com>
Date:   Mon Sep 5 18:26:06 2022 +0100

    gdb/testsuite/lib/future.exp: follow dejagnu default_target_compile
    
    GDB's testsuite can override dejagnu's default_target_compile if the
    system provided dejagnu installation does not provide support to compile
    languages GDB needs.
    
    Recent version of dejagnu (1.6.3, installed on RHEL-9) includes ba60272
    "Establish a default C compiler by evaluating [find_gcc] if no other
    compiler is given."[1].  This commit removed calls such as
    `set_board_info compiler  "[find_gcc]"` from the various baseboards
    and has default_target_compile call `find_gcc` itself to find a compiler
    if none was specified by the board description.
    
    On systems with dejagnu-1.6.3, if GDB's overrides is needed to support
    languages still unknown to dejagnu, we end up in the following
    situation:
      - The system board files do not set the C compiler anymore,
      - GDB's replacement for default_target_compile assumes that the
        compiler should have been set up by the board file.
    
    In this situation, no one sets the C compiler for the board and as a
    result many test are not compiled and not executed:
    
        [...]
        Running .../gdb/testsuite/gdb.base/bt-on-error-and-warning.exp ...
        gdb compile failed, default_target_compile: No compiler to compile with
        Running .../gdb/testsuite/gdb.base/dprintf-non-stop.exp ...
        gdb compile failed, default_target_compile: No compiler to compile with
        Running .../gdb/testsuite/gdb.base/structs3.exp ...
        gdb compile failed, default_target_compile: No compiler to compile with
        [...]
    
    We are observing this error with ROCgdb[2], a downstream port of GDB
    supporting AMD GPUs.  This port needs to use GDB's override of
    default_target_compile to compile HIP programs since dejagnu does not
    provide support for this language yet.
    
    This patch changes gdb_default_target_compile_1 in a similar way
    default_target_compile has been updated so both implementations remain
    compatible.  Even if this is not strictly required by GDB just yet,
    I believe keeping both implementations in sync desirable.
    
    Using board files provided with dejagnu <=1.6.2 is still supported: if
    the compiler is set by the board file, gdb_default_target_compile_1 uses
    it and does not need `find_gcc`.
    
    Patch tested on x86_64 RHEL-9 and ubuntu-20.04 on top of GDB and ROCgdb.
    
    [1] http://git.savannah.gnu.org/gitweb/?p=dejagnu.git;a=commit;h=ba60272a5ac6f6a7012acca03f596a6ed003f044
    [2] https://github.com/ROCm-Developer-Tools/ROCgdb
    
    Change-Id: Ibff52684d9cab8243a7c6748ecbd29f50c37e669

Diff:
---
 gdb/testsuite/lib/future.exp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/gdb/testsuite/lib/future.exp b/gdb/testsuite/lib/future.exp
index 36dd611d61c..17736ed360a 100644
--- a/gdb/testsuite/lib/future.exp
+++ b/gdb/testsuite/lib/future.exp
@@ -403,7 +403,11 @@ proc gdb_default_target_compile_1 {source destfile type options} {
     }
 
     if { $compiler == "" } {
-	set compiler [board_info $dest compiler]
+	if { [board_info $dest exists compiler] } {
+	    set compiler [board_info $dest compiler]
+	} elseif { $compiler_type eq "c" } {
+	    set compiler [find_gcc]
+	}
 	if { $compiler == "" } {
 	    return "default_target_compile: No compiler to compile with"
 	}