Re: [PATCH 2/7] [gdb/testsuite] fix test gdb.base/print-file-var.exp for remote execution

[Tom de Vries <tdevries@suse.de>]

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On 10/25/22 18:29, Ivan Tetyushkin wrote:
> ---
>   gdb/testsuite/gdb.base/print-file-var.exp | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/gdb/testsuite/gdb.base/print-file-var.exp b/gdb/testsuite/gdb.base/print-file-var.exp
> index 9abe87d7758..73137630fed 100644
> --- a/gdb/testsuite/gdb.base/print-file-var.exp
> +++ b/gdb/testsuite/gdb.base/print-file-var.exp
> @@ -42,6 +42,8 @@ proc test {hidden dlopen version_id_main lang} {
>       set libobj1 [standard_output_file ${lib1}$suffix.so]
>       set libobj2 [standard_output_file ${lib2}$suffix.so]
>   
> +    set runtimelibobj2 [get_runtime_file $libobj2]
> +
>       set lib_opts { debug $lang }
>       lappend lib_opts "additional_flags=-DHIDDEN=$hidden"
>   
> @@ -60,7 +62,7 @@ proc test {hidden dlopen version_id_main lang} {
>       set link_opts [list debug shlib=${libobj1}]
>   
>       if {$dlopen} {
> -	lappend main_opts "additional_flags=-DSHLIB_NAME=\"$libobj2\""
> +	lappend main_opts "additional_flags=-DSHLIB_NAME=\"$runtimelibobj2\""
>   	lappend link_opts "shlib_load"
>       } else {
>   	lappend link_opts "shlib=${libobj2}"

I get this test-case passing by avoiding to use an absolute file name:
...
diff --git a/gdb/testsuite/gdb.base/print-file-var.exp 
b/gdb/testsuite/gdb.base/print-file-
var.exp
index 9abe87d7758..338840cb05e 100644
--- a/gdb/testsuite/gdb.base/print-file-var.exp
+++ b/gdb/testsuite/gdb.base/print-file-var.exp
@@ -60,7 +60,7 @@ proc test {hidden dlopen version_id_main lang} {
      set link_opts [list debug shlib=${libobj1}]

      if {$dlopen} {
-       lappend main_opts "additional_flags=-DSHLIB_NAME=\"$libobj2\""
+       lappend main_opts "additional_flags=-DSHLIB_NAME=\"[file tail 
$libobj2]\""
         lappend link_opts "shlib_load"
      } else {
         lappend link_opts "shlib=${libobj2}"
...
which means that the file is found relative to $ORIGIN, as is the case 
for $dlopen == 0.

I'm not entirely happy with this fix, because what we'd rather want is 
to use the name as returned by remote_download, but that's done in 
gdb_load_shlib later on (which also handles shlib_target_file, so 
actually, the name as returned by this proc is the one we really want), 
so it's not available yet at the time we do the compilation.

I've thought about allowing gdb_load_shlib to be called without gdb 
instance, and for cases where there's no instance, registering the 
solib-search-path setting to be done at gdb start.  This will allow us 
to move the gdb_load_shlib calls to before the compilation, such that we 
can use the result to set -DSHLIB_NAME.  But I think it's a solution 
bound to cause confusion because things happen under the hood.

Alternatively, we can try to not pass in the name into compilation 
(working around only some of the problems related to remote host 
testing, see https://sourceware.org/bugzilla/show_bug.cgi?id=16947), but 
that also has its limitations: we need to be able to patch target memory 
or the ability to use argv.

Perhaps splitting up the functionality in gdb_load_shlib makes the most 
sense.  By default, it'll do the same as before, but by calling it 
twice, once with -only-download, and once with -no-download can we get 
the solib name before starting gdb.

I've given this a try in patch attached below.

Ivan, could you check if the patch fixes the gdb.base/print-file-var.exp 
test-case for you?

Thanks,
- Tom

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From b072645433f83d62a4b7cf857d3d50f0dd7e0c75 Mon Sep 17 00:00:00 2001
From: Tom de Vries <tdevries@suse.de>
Date: Sun, 6 Nov 2022 11:26:23 +0100
Subject: [PATCH 3/3] [gdb/testsuite] Fix gdb.base/print-file-var.exp for
 remote target

---
 gdb/testsuite/gdb.base/print-file-var.exp |  6 ++-
 gdb/testsuite/lib/gdb.exp                 | 48 +++++++++++++++++------
 2 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/gdb/testsuite/gdb.base/print-file-var.exp b/gdb/testsuite/gdb.base/print-file-var.exp
index 9abe87d7758..abdbbbfdce4 100644
--- a/gdb/testsuite/gdb.base/print-file-var.exp
+++ b/gdb/testsuite/gdb.base/print-file-var.exp
@@ -59,8 +59,10 @@ proc test {hidden dlopen version_id_main lang} {
     set main_opts [list debug $lang]
     set link_opts [list debug shlib=${libobj1}]
 
+    set target_libobj2 [gdb_load_shlib $libobj2 -only-download]
+
     if {$dlopen} {
-	lappend main_opts "additional_flags=-DSHLIB_NAME=\"$libobj2\""
+	lappend main_opts "additional_flags=-DSHLIB_NAME=\"$target_libobj2\""
 	lappend link_opts "shlib_load"
     } else {
 	lappend link_opts "shlib=${libobj2}"
@@ -79,7 +81,7 @@ proc test {hidden dlopen version_id_main lang} {
 
     clean_restart $executable
     gdb_load_shlib $libobj1
-    gdb_load_shlib $libobj2
+    gdb_load_shlib $libobj2 -no-download
 
     if ![runto_main] {
 	return -1
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index e2cda30b95a..5328afb27e8 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -5873,24 +5873,46 @@ proc gdb_remote_download {dest fromfile {tofile {}}} {
 #
 # Copy the listed library to the target.
 
-proc gdb_load_shlib { file } {
+proc gdb_load_shlib { file args } {
     global gdb_spawn_id
 
-    if ![info exists gdb_spawn_id] {
-	perror "gdb_load_shlib: GDB is not running"
+    set download 1
+    set solib-search-path 1
+    parse_args {
+	{no-download}
+	{only-download}
+    }
+    if { ${no-download} && ${only-download} } {
+	perror \
+	    "gdb_load_shlib: Cannot use both -no-download and -only-download"
+    }
+    if { ${no-download} } {
+	set download 0
+    }
+    if { ${only-download} } {
+	set solib-search-path 0
     }
 
-    set dest [gdb_remote_download target [shlib_target_file $file]]
+    set dest ""
+    if { $download } {
+	set dest [gdb_remote_download target [shlib_target_file $file]]
+    }
 
-    if {[is_remote target]} {
-	# If the target is remote, we need to tell gdb where to find the
-	# libraries.
-	#
-	# We could set this even when not testing remotely, but a user
-	# generally won't set it unless necessary.  In order to make the tests
-	# more like the real-life scenarios, we don't set it for local testing.
-	gdb_test "set solib-search-path [file dirname $file]" "" \
-	    "set solib-search-path for [file tail $file]"
+    if { ${solib-search-path} } {
+	if ![info exists gdb_spawn_id] {
+	    perror "gdb_load_shlib: GDB is not running"
+	}
+
+	if {[is_remote target]} {
+	    # If the target is remote, we need to tell gdb where to find the
+	    # libraries.
+	    #
+	    # We could set this even when not testing remotely, but a user
+	    # generally won't set it unless necessary.  In order to make the tests
+	    # more like the real-life scenarios, we don't set it for local testing.
+	    gdb_test "set solib-search-path [file dirname $file]" "" \
+		"set solib-search-path for [file tail $file]"
+	}
     }
 
     return $dest
-- 
2.35.3