Backport "[gdb/breakpoint] Fix assert in jit_event_handler"

Resolves: rhbz#2130624

_gdb.spec.Patch.include

@@ -471,3 +471,7 @@ Patch113: gdb-rhbz2155439-assert-failure-copy_type.patch
 # (Tom de Vries)
 Patch114: gdb-fix-gdb.base-printcmds-s390x-regressions.patch
 
+# Backport "[gdb/breakpoint] Fix assert in jit_event_handler"
+# (Tom de Vries, RHBZ2130624)
+Patch115: gdb-rhbz-2130624-assert_in_jit_event_handler.patch
+

_gdb.spec.patch.include

@@ -112,3 +112,4 @@
 %patch112 -p1
 %patch113 -p1
 %patch114 -p1
+%patch115 -p1

_patch_order

@@ -112,3 +112,4 @@ gdb-rhbz1870017-p10-plt-prologue-skipping.patch
 gdb-rhbz2086761-unknown-cfa-rule.patch
 gdb-rhbz2155439-assert-failure-copy_type.patch
 gdb-fix-gdb.base-printcmds-s390x-regressions.patch
+gdb-rhbz-2130624-assert_in_jit_event_handler.patch

gdb-rhbz-2130624-assert_in_jit_event_handler.patch

@@ -0,0 +1,115 @@
+From FEDORA_PATCHES Mon Sep 17 00:00:00 2001
+From: Tom de Vries <tdevries@suse.de>
+Date: Fri, 21 May 2021 15:09:14 +0200
+Subject: gdb-rhbz-2130624-assert_in_jit_event_handler.patch
+
+;; Backport "[gdb/breakpoint] Fix assert in jit_event_handler"
+;; (Tom de Vries, RHBZ2130624)
+
+Consider a minimal test-case test.c:
+...
+int main (void) { return 0; }
+...
+which we can compile into llvm byte code using clang:
+...
+$ clang -g -S -emit-llvm --target=x86_64-unknown-unknown-elf test.c
+...
+and then run using lli, which uses the llvm jit:
+...
+$ lli test.ll
+...
+
+If we run this under gdb, we run into an assert:
+...
+$ gdb -q -batch -ex run --args /usr/bin/lli test.ll
+Dwarf Error: Cannot not find DIE at 0x18a936e7 \
+  [from module libLLVM.so.10-10.0.1-lp152.30.4.x86_64.debug]
+
+[Thread debugging using libthread_db enabled]
+Using host libthread_db library "/lib64/libthread_db.so.1".
+src/gdb/jit.c:1178: internal-error: \
+  void jit_event_handler(gdbarch*, objfile*): \
+  Assertion `jiter->jiter_data != nullptr' failed.
+...
+
+This is caused by the following.
+
+When running jit_breakpoint_re_set_internal, we first handle
+libLLVM.so.10.debug, and set a jit breakpoint.
+
+Next we handle libLLVM.so.10:
+...
+(gdb) p the_objfile.original_name
+$42 = 0x2494170 "libLLVM.so.10"
+...
+but the minimal symbols we find are from libLLVM.so.10.debug:
+...
+(gdb) p reg_symbol.objfile.original_name
+$43 = 0x38e7c50 "libLLVM.so.10-10.0.1-lp152.30.4.x86_64.debug"
+(gdb) p desc_symbol.objfile.original_name
+$44 = 0x38e7c50 "libLLVM.so.10-10.0.1-lp152.30.4.x86_64.debug"
+...
+and consequently, the objf_data is the one from libLLVM.so.10.debug:
+...
+      jiter_objfile_data *objf_data
+        = get_jiter_objfile_data (reg_symbol.objfile);
+...
+and so we hit this:
+...
+      if (objf_data->cached_code_address == addr)
+        continue;
+...
+and no second jit breakpoint is inserted.
+
+Subsequently, the jit breakpoint is triggered and handled, but when finding
+the symbol for the breakpoint address we get:
+...
+(gdb) p jit_bp_sym.objfile.original_name
+$52 = 0x2494170 "libLLVM.so.10"
+...
+
+The assert 'jiter->jiter_data != nullptr' triggers because it checks
+libLLVM.so.10 while the one with jiter_data setup is libLLVM.so.10.debug.
+
+This fixes the assert:
+...
+       jiter_objfile_data *objf_data
+-        = get_jiter_objfile_data (reg_symbol.objfile);
+-        = get_jiter_objfile_data (the_objfile);
+...
+but consequently we'll have two jit breakpoints, so we also make sure we don't
+set a jit breakpoint on separate debug objects like libLLVM.so.10.debug.
+
+Tested on x86_64-linux.
+
+gdb/ChangeLog:
+
+2021-05-21  Tom de Vries  <tdevries@suse.de>
+
+	PR breakpoint/27889
+	* jit.c (jit_breakpoint_re_set_internal): Skip separate debug
+	objects.  Call get_jiter_objfile_data with the_objfile.
+
+diff --git a/gdb/jit.c b/gdb/jit.c
+--- a/gdb/jit.c
++++ b/gdb/jit.c
+@@ -893,6 +893,10 @@ jit_breakpoint_re_set_internal (struct gdbarch *gdbarch, program_space *pspace)
+ {
+   for (objfile *the_objfile : pspace->objfiles ())
+     {
++      /* Skip separate debug objects.  */
++      if (the_objfile->separate_debug_objfile_backlink != nullptr)
++	continue;
++
+       if (the_objfile->skip_jit_symbol_lookup)
+ 	continue;
+ 
+@@ -919,7 +923,7 @@ jit_breakpoint_re_set_internal (struct gdbarch *gdbarch, program_space *pspace)
+ 	}
+ 
+       jiter_objfile_data *objf_data
+-	= get_jiter_objfile_data (reg_symbol.objfile);
++	= get_jiter_objfile_data (the_objfile);
+       objf_data->register_code = reg_symbol.minsym;
+       objf_data->descriptor = desc_symbol.minsym;
+ 

gdb.spec

@@ -1158,6 +1158,10 @@ fi
 %endif
 
 %changelog
+* Mon Mar 27 2023 Bruno Larsen <blarsen@redhat.com>
+- Backport "[gdb/breakpoint] Fix assert in jit_event_handler"
+  (Tom de Vries, RHBZ 2130624)
+
 * Wed Mar 23 2023 Bruno Larsen <blarsen@redhat.com>
 - Bakport "Fix assertion failure in copy_type"
   (Tom Tromey, RHBZ 2155439)