[binutils-gdb] [gdb/tdep] Fix gdb.base/msym-bp-shl.exp for ppc64le

[Tom de Vries <vries@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=2650ea9730e31fc5c9111afc1a689dbca76707f5

commit 2650ea9730e31fc5c9111afc1a689dbca76707f5
Author: Tom de Vries <tdevries@suse.de>
Date:   Mon Nov 28 10:50:03 2022 +0100

    [gdb/tdep] Fix gdb.base/msym-bp-shl.exp for ppc64le
    
    With test-case gdb.base/msym-bp-shl.exp on powerpc64le-linux, I run into:
    ...
    (gdb) PASS: gdb.base/msym-bp-shl.exp: debug=0: before run: break foo
    info breakpoint^M
    Num     Type           Disp Enb Address            What^M
    1       breakpoint     keep y   <MULTIPLE>         ^M
    1.1                         y   0x00000000000008d4 <foo+12>^M
    1.2                         y   0x0000000000000a34 crti.S:88^M
    (gdb) FAIL: gdb.base/msym-bp-shl.exp: debug=0: before run: info breakpoint
    ...
    
    The problem is that the prologue skipper walks from foo@plt at 0xa28 to 0xa34:
    ...
    0000000000000a28 <foo@plt>:
     a28:   c0 ff ff 4b     b       9e8 <__glink_PLTresolve>
    
    Disassembly of section .fini:
    
    0000000000000a2c <_fini>:
     a2c:   02 00 4c 3c     addis   r2,r12,2
     a30:   d4 74 42 38     addi    r2,r2,29908
     a34:   a6 02 08 7c     mflr    r0
    ...
    
    This is caused by ppc_elfv2_elf_make_msymbol_special which marks foo@plt as
    having a local entry point, due to incorrectly accessing an asymbol struct
    using a (larger) elf_symbol_type.
    
    Fix this by simply ignoring artificial symbols in
    ppc_elfv2_elf_make_msymbol_special.
    
    Tested on powerpc64le.
    
    Approved-By: Ulrich Weigand <uweigand@de.ibm.com>
    Reviewed-By: Carl Love <cel@us.ibm.com>
    Tested-By: Carl Love <cel@us.ibm.com>
    PR tdep/29814
    Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29814

Diff:
---
 gdb/ppc-linux-tdep.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/gdb/ppc-linux-tdep.c b/gdb/ppc-linux-tdep.c
index cc5a26431ba..39d692b2764 100644
--- a/gdb/ppc-linux-tdep.c
+++ b/gdb/ppc-linux-tdep.c
@@ -1632,6 +1632,11 @@ ppc_linux_core_read_description (struct gdbarch *gdbarch,
 static void
 ppc_elfv2_elf_make_msymbol_special (asymbol *sym, struct minimal_symbol *msym)
 {
+  if ((sym->flags & BSF_SYNTHETIC) != 0)
+    /* ELFv2 synthetic symbols (the PLT stubs and the __glink_PLTresolve
+       trampoline) do not have a local entry point.  */
+    return;
+
   elf_symbol_type *elf_sym = (elf_symbol_type *)sym;
 
   /* If the symbol is marked as having a local entry point, set a target