Re: [PATCH 1/2] Add lld(linker) specific option.

[Simon Marchi <simon.marchi@polymtl.ca>]

On 2022-03-30 07:21, Balasubrmanian, Vignesh wrote:
> Simon,
> 
> Thanks for the suggestion.
> Yes, our clang is configured to use lld.
> I modified it as you suggested and attached the same.
> 
> Thanks,
> vigneshbalu

Thanks, I did a few adjustements to the patch and commit message, and
pushed it as below.

Simon


From 2bb8c72b39f4dcce0be292b2c701edbe4dd4ca7c Mon Sep 17 00:00:00 2001
From: Vignesh Balasubramanian <Vignesh.Balasubrmanian@amd.com>
Date: Wed, 30 Mar 2022 16:29:43 +0530
Subject: [PATCH] gdb/testsuite: add text_segment option to gdb_compile

LLVM's lld linker doesn't have the "-Ttext-segment" option, but
"--image-base" can be used instead.

To centralize the logic of checking which option is supported, add the
text_segment option to gdb_compile.  Change tests that are currently
using -Ttext-segment to use that new option instead.

This patch fixes only compilation error, for example:

Before:

    $ make check TESTS="gdb.base/jit-elf.exp" RUNTESTFLAGS="CC_FOR_TARGET=clang LDFLAGS_FOR_TARGET=-fuse-ld=ld"
    Running /home/simark/src/binutils-gdb/gdb/testsuite/gdb.base/jit-elf.exp ...
    gdb compile failed, clang-13: warning: -Xlinker -Ttext-segment=0x7000000: 'linker' input unused [-Wunused-command-line-argument]

After:

    $ make check TESTS="gdb.base/jit-elf.exp" RUNTESTFLAGS="CC_FOR_TARGET=clang LDFLAGS_FOR_TARGET=-fuse-ld=ld"
    Running /home/simark/src/binutils-gdb/gdb/testsuite/gdb.base/jit-elf.exp ...
    FAIL: gdb.base/jit-elf.exp: one_jit_test-1: continue to breakpoint: break here 1
    FAIL: gdb.base/jit-elf.exp: one_jit_test-1: continue to breakpoint: break here 2
    FAIL: gdb.base/jit-elf.exp: one_jit_test-2: continue to breakpoint: break here 1
    FAIL: gdb.base/jit-elf.exp: one_jit_test-2: info function ^jit_function
    FAIL: gdb.base/jit-elf.exp: one_jit_test-2: continue to breakpoint: break here 2
    FAIL: gdb.base/jit-elf.exp: attach: one_jit_test-2: continue to breakpoint: break here 1
    FAIL: gdb.base/jit-elf.exp: attach: one_jit_test-2: break here 1: attach
    FAIL: gdb.base/jit-elf.exp: PIE: one_jit_test-1: continue to breakpoint: break here 1
    FAIL: gdb.base/jit-elf.exp: PIE: one_jit_test-1: continue to breakpoint: break here 2

                    === gdb Summary ===

    # of expected passes            26
    # of unexpected failures        9

Change-Id: I3678c5c9bbfc2f80671698e28a038e6b3d14e635
---
 gdb/testsuite/gdb.arch/arm-bl-branch-dest.exp |  2 +-
 .../gdb.base/execl-update-breakpoints.exp     | 16 +-------
 gdb/testsuite/gdb.threads/step-over-exec.exp  |  4 +-
 gdb/testsuite/lib/gdb.exp                     | 39 +++++++++++++++++++
 gdb/testsuite/lib/jit-elf-helpers.exp         |  8 ++--
 5 files changed, 48 insertions(+), 21 deletions(-)

diff --git a/gdb/testsuite/gdb.arch/arm-bl-branch-dest.exp b/gdb/testsuite/gdb.arch/arm-bl-branch-dest.exp
index cebeb629a9f4..34d98aec96e3 100644
--- a/gdb/testsuite/gdb.arch/arm-bl-branch-dest.exp
+++ b/gdb/testsuite/gdb.arch/arm-bl-branch-dest.exp
@@ -26,7 +26,7 @@ standard_testfile
 # the "-Wl,-Ttext-segment" option compile the binary.
 
 if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} \
-    [list debug ldflags=-Wl,-Ttext-segment=0xb0000000]] } {
+    [list debug text_segment=0xb0000000]] } {
     return -1
 }
 
diff --git a/gdb/testsuite/gdb.base/execl-update-breakpoints.exp b/gdb/testsuite/gdb.base/execl-update-breakpoints.exp
index 8a9bdf662160..29647958e65c 100644
--- a/gdb/testsuite/gdb.base/execl-update-breakpoints.exp
+++ b/gdb/testsuite/gdb.base/execl-update-breakpoints.exp
@@ -32,20 +32,8 @@ if { [gdb_compile [file join $srcdir $subdir $srcfile] $objfile \
     return -1
 }
 
-set opts1_ld [list debug ldflags=-Wl,-Ttext-segment=0x1000000]
-set opts1_gold [list debug ldflags=-Wl,-Ttext=0x1000000]
-set opts2_ld [list debug ldflags=-Wl,-Ttext-segment=0x2000000]
-set opts2_gold [list debug ldflags=-Wl,-Ttext=0x2000000]
-
-if { [gdb_compile $objfile $exec1 executable $opts1_ld] != "" } {
-    # Old gold linker versions don't support -Ttext-segment.  Fall
-    # back to -Ttext.
-    if { [gdb_compile $objfile $exec1 executable $opts1_gold] != ""
-	 || [gdb_compile $objfile $exec2 executable $opts2_gold] != ""} {
-	untested "link failed"
-	return -1
-    }
-} elseif { [gdb_compile $objfile $exec2 executable $opts2_ld] != "" } {
+if { [gdb_compile $objfile $exec1 executable {debug text_segment=0x1000000}] != ""
+     || [gdb_compile $objfile $exec2 executable {debug text_segment=0x2000000}] != ""} {
     untested "link failed"
     return -1
 }
diff --git a/gdb/testsuite/gdb.threads/step-over-exec.exp b/gdb/testsuite/gdb.threads/step-over-exec.exp
index 9e252e65f97f..783f865585c0 100644
--- a/gdb/testsuite/gdb.threads/step-over-exec.exp
+++ b/gdb/testsuite/gdb.threads/step-over-exec.exp
@@ -47,8 +47,8 @@ proc do_test { execr_thread different_text_segments displaced_stepping } {
     set execd_opts [list debug]
 
     if { $different_text_segments } {
-	lappend execr_opts "ldflags=-Wl,-Ttext-segment=0x600000"
-	lappend execd_opts "ldflags=-Wl,-Ttext-segment=0x800000"
+	lappend execr_opts "text_segment=0x600000"
+	lappend execd_opts "text_segment=0x800000"
     }
 
     if { $execr_thread == "leader" } {
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 7c35fbb18c4e..10f78736629e 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -4351,6 +4351,7 @@ set gdb_saved_set_unbuffered_mode_obj ""
 #   - nopie: Prevent creation of PIE executables.
 #   - macros: Add the required compiler flag to include macro information in
 #     debug information
+#   - text_segment=addr: Tell the linker to place the text segment at ADDR.
 #
 # And here are some of the not too obscure options understood by DejaGnu that
 # influence the compilation:
@@ -4470,6 +4471,19 @@ proc gdb_compile {source dest type options} {
 	} elseif { $opt == "getting_compiler_info" } {
 	    # If this is set, calling test_compiler_info will cause recursion.
 	    set getting_compiler_info 1
+        } elseif {[regexp "^text_segment=(.*)" $opt dummy_var addr]} {
+            if { [linker_supports_Ttext_segment_flag] } {
+                # For GNU ld.
+                lappend new_options "ldflags=-Wl,-Ttext-segment=$addr"
+            } elseif { [linker_supports_image_base_flag] } {
+                # For LLVM's lld.
+                lappend new_options "ldflags=-Wl,--image-base=$addr"
+            } elseif { [linker_supports_Ttext_flag] } {
+                # For old GNU gold versions.
+                lappend new_options "ldflags=-Wl,-Ttext=$addr"
+            } else {
+                error "Don't know how to handle text_segment option."
+            }
         } else {
             lappend new_options $opt
         }
@@ -8235,6 +8249,31 @@ gdb_caching_proc have_fuse_ld_gold {
     return [gdb_simple_compile $me $src executable $flags]
 }
 
+# Return 1 if linker supports -Ttext-segment, otherwise return 0.
+gdb_caching_proc linker_supports_Ttext_segment_flag {
+    set me "linker_supports_Ttext_segment_flag"
+    set flags additional_flags="-Wl,-Ttext-segment=0x7000000"
+    set src { int main() { return 0; } }
+    return [gdb_simple_compile $me $src executable $flags]
+}
+
+# Return 1 if linker supports -Ttext, otherwise return 0.
+gdb_caching_proc linker_supports_Ttext_flag {
+    set me "linker_supports_Ttext_flag"
+    set flags additional_flags="-Wl,-Ttext=0x7000000"
+    set src { int main() { return 0; } }
+    return [gdb_simple_compile $me $src executable $flags]
+}
+
+# Return 1 if linker supports --image-base, otherwise 0.
+gdb_caching_proc linker_supports_image_base_flag {
+    set me "linker_supports_image_base_flag"
+    set flags additional_flags="-Wl,--image-base=0x7000000"
+    set src { int main() { return 0; } }
+    return [gdb_simple_compile $me $src executable $flags]
+}
+
+
 # Return 1 if compiler supports scalar_storage_order attribute, otherwise
 # return 0.
 gdb_caching_proc supports_scalar_storage_order_attribute {
diff --git a/gdb/testsuite/lib/jit-elf-helpers.exp b/gdb/testsuite/lib/jit-elf-helpers.exp
index af70b11644ce..b699917f2090 100644
--- a/gdb/testsuite/lib/jit-elf-helpers.exp
+++ b/gdb/testsuite/lib/jit-elf-helpers.exp
@@ -88,14 +88,14 @@ proc compile_and_download_n_jit_so {jit_solib_basename jit_solib_srcfile count}
 	# wouldn't work for .debug sections.  Also, output for "info
 	# function" changes when debug info is present.
 	set addr [format 0x%x [expr $jit_load_address + $jit_load_increment * [expr $i-1]]]
-	# Using -Ttext-segment flag to ask linked to relocate everything
-	# in the compiled shared library against a fixed base address.  Combined
+
+	# Use "text_segment=..." to ask the linker to relocate everything in the
+	# compiled shared library against a fixed base address.  Combined
 	# with mapping the resulting binary to the same fixed base it allows
 	# to dynamically execute functions from it without any further adjustments.
 	set options [list \
 	    additional_flags=-DFUNCTION_NAME=[format "jit_function_%04d" $i] \
-	    additional_flags=-Xlinker \
-	    additional_flags=-Ttext-segment=$addr]
+	    text_segment=$addr]
 	if { [gdb_compile_shlib ${jit_solib_srcfile} ${binfile} \
 		  $options] != "" } {
 	    set f [file tail $binfile]

base-commit: a5c69b1e49bae4d0dcb20f324cebb310c63495c6
-- 
2.35.2