[binutils-gdb] [gdb/testsuite] Fix gdb.cp/step-and-next-inline.exp with -fcf-protection

[binutils-gdb] [gdb/testsuite] Fix gdb.cp/step-and-next-inline.exp with -fcf-protection

[Tom de Vries]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=b1b0f69cb4a2ccd421419f9703edfcc5c3032dc0

commit b1b0f69cb4a2ccd421419f9703edfcc5c3032dc0
Author: Tom de Vries <tdevries@suse.de>
Date:   Fri Dec 30 14:00:39 2022 +0100

    [gdb/testsuite] Fix gdb.cp/step-and-next-inline.exp with -fcf-protection
    
    On Ubuntu 22.04.1 x86_64, I run into:
    ...
    (gdb) PASS: gdb.cp/step-and-next-inline.exp: no_header: not in inline 1
    next^M
    51        if (t != NULL^M
    (gdb) FAIL: gdb.cp/step-and-next-inline.exp: no_header: next step 1
    ...
    
    This is due to -fcf-protection, which adds the endbr64 at the start of get_alias_set:
    ...
    0000000000001180 <_Z13get_alias_setP4tree>:
        1180:       f3 0f 1e fa             endbr64
        1184:       48 85 ff                test   %rdi,%rdi
    ...
    so the extra insn gets an is-stmt line number entry:
    ...
    INDEX  LINE   ADDRESS            IS-STMT PROLOGUE-END
      ...
    11     50     0x0000000000001180 Y
    12     50     0x0000000000001180
    13     51     0x0000000000001184 Y
    14     54     0x0000000000001184
    ...
    and when stepping into get_alias_set we step to line 50:
    ...
    (gdb) PASS: gdb.cp/step-and-next-inline.exp: no_header: in main
    step^M
    get_alias_set (t=t@entry=0x555555558018 <xx>) at step-and-next-inline.cc:50^M
    50      {^M
    ...
    
    In contrast, with -fcf-protection=none, we get:
    ...
    0000000000001170 <_Z13get_alias_setP4tree>:
        1170:       48 85 ff                test   %rdi,%rdi
    ...
    and:
    ...
    INDEX  LINE   ADDRESS            IS-STMT PROLOGUE-END
      ...
    11     50     0x0000000000001170 Y
    12     51     0x0000000000001170 Y
    13     54     0x0000000000001170
    ...
    so when stepping into get_alias_set we step to line 51:
    ...
    (gdb) PASS: gdb.cp/step-and-next-inline.exp: no_header: in main
    step^M
    get_alias_set (t=t@entry=0x555555558018 <xx>) at step-and-next-inline.cc:51^M
    51        if (t != NULL^M
    ...
    
    Fix this by rewriting the gdb_test issuing the step command to check which
    line the step lands on, and issuing an extra next if needed.
    
    Tested on x86_64-linux, both with and without -fcf-protection=none.
    
    PR testsuite/29920
    Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29920

Diff:
---
 gdb/testsuite/gdb.cp/step-and-next-inline.exp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/gdb/testsuite/gdb.cp/step-and-next-inline.exp b/gdb/testsuite/gdb.cp/step-and-next-inline.exp
index 8b2ad2766bc..36fac239e2f 100644
--- a/gdb/testsuite/gdb.cp/step-and-next-inline.exp
+++ b/gdb/testsuite/gdb.cp/step-and-next-inline.exp
@@ -60,7 +60,16 @@ proc do_test { use_header } {
     }
 
     gdb_test "bt" "\\s*\\#0\\s+main.*" "in main"
-    gdb_test "step" ".*" "step into get_alias_set"
+    set line1 {\t\{}
+    set line2 {\t  if \(t != NULL}
+    gdb_test_multiple "step" "step into get_alias_set" {
+	-re -wrap $line1 {
+	    gdb_test "next" $line2 $gdb_test_name
+	}
+	-re -wrap $line2 {
+	    pass $gdb_test_name
+	}
+    }
     gdb_test "bt" "\\s*\\#0\\s+get_alias_set\[^\r\]*${srcfile}:.*" \
 	"not in inline 1"