gdb: Update linkage name lookup function to allow mst_file_data/bss types.

From the commit 667ed4b14ddaa9af196481f1757c0e517e80b6ed onward, instead
of normal name GDB looks for the "jit_descriptor" linkage name in the JIT
code initialization.  Without this change, the function
"lookup_minimal_symbol_linkage", only matches the non-static data.  So in
case jit_debugger is static type then setting up breakpoint in the JIT code
fails.  Issue is seen for the intel compilers, where jit_debug_descriptor has
static type i.e. "mst_file_data".  Hence lookup_minimal_symbol_linkage returns
nullptr for it.  So, in this case breakpoint does not hit in the JIT code.
To resolve this, the commit introduces a new boolean argument to the
lookup_minimal_symbol_linkage function.  This argument allows the function to
also match mst_file_data and mst_file_bss types when set to true.  The
function is called with this new argument set to true only from JIT code
initialization handling, ensuring that the current behavior remains unchanged
for other cases.  Because handling of static types of data symbols for all cases
result in regression for "gdb.base/print-file-var.exp" test.

Example of minsym for the JIT code emitted by the intel compilers where
lookup_minimal_symbol_linkage fails without this change because jit_debugger
type is "mst_file_data".

(top-gdb) p *msymbol
$1 = {<general_symbol_info> =
{m_name = 0x7fffcc77dc95 "__jit_debug_descriptor",
m_value = {ivalue = 84325936, block = 0x506b630,
bytes = 0x506b630 <error: Cannot access memory at address 0x506b630>,
address = 0x506b630, unrel_addr = (unknown: 0x506b630),
common_block = 0x506b630, chain = 0x506b630},
language_specific = {obstack = 0x0, demangled_name = 0x0},
m_language = language_unknown, ada_mangled = 0, m_section = 29},
m_size = 24, filename = 0x55555a751b70 "JITLoaderGDB.cpp",
m_type = mst_file_data, created_by_gdb = 0,
m_target_flag_1 = 0, m_target_flag_2 = 0, m_has_size = 1,
name_set = 1, hash_next = 0x55555b86e4f0, demangled_hash_next = 0x0}

Updated the test "jit-elf-so.exp" to test the static type of jit_descriptor
object.

Approved-By: Tom Tromey <tom@tromey.com>

2 files changed, 10 insertions, 3 deletions

diff --git a/gdb/testsuite/gdb.base/jit-elf-so.exp b/gdb/testsuite/gdb.base/jit-elf-so.exp
index f28c181..2759c64 100644
--- a/gdb/testsuite/gdb.base/jit-elf-so.exp
+++ b/gdb/testsuite/gdb.base/jit-elf-so.exp
@@ -46,7 +46,8 @@ set jit_solib_srcfile ${srcdir}/${subdir}/${jit_solib_basename}.c
 # On failure, return -1.
 proc compile_jit_dlmain {options} {
     global main_loader_srcfile main_loader_binfile main_loader_basename
-    set options [concat $options debug]
+    set options [concat $options debug \
+	additional_flags=-DJIT_DESCRIPTOR_LINKAGE="static"]
 
     if { [gdb_compile ${main_loader_srcfile} ${main_loader_binfile} \
 	    executable $options] != "" } {
@@ -133,7 +134,8 @@ proc one_jit_test {solib_binfiles_target match_str} {
 
 # Compile the main code (which loads the JIT objects) as a shared library.
 if { [compile_jit_elf_main_as_so $main_solib_srcfile $main_solib_binfile \
-	{additional_flags="-DMAIN=jit_dl_main"}] < 0 } {
+	{additional_flags="-DMAIN=jit_dl_main" \
+	    additional_flags="-DJIT_DESCRIPTOR_LINKAGE=static"}] < 0 } {
     return
 }
 
diff --git a/gdb/testsuite/gdb.base/jit-protocol.h b/gdb/testsuite/gdb.base/jit-protocol.h
index d143dd6..3e85c19 100644
--- a/gdb/testsuite/gdb.base/jit-protocol.h
+++ b/gdb/testsuite/gdb.base/jit-protocol.h
@@ -26,6 +26,10 @@
 
 #include <stdint.h>
 
+#ifndef JIT_DESCRIPTOR_LINKAGE
+#define JIT_DESCRIPTOR_LINKAGE
+#endif
+
 typedef enum
 {
   JIT_NOACTION = 0,
@@ -51,7 +55,8 @@ struct jit_descriptor
   struct jit_code_entry *first_entry;
 };
 
-struct jit_descriptor __jit_debug_descriptor = { 1, 0, 0, 0 };
+JIT_DESCRIPTOR_LINKAGE struct jit_descriptor __jit_debug_descriptor
+  = { 1, 0, 0, 0 };
 
 void __attribute__((noinline)) __jit_debug_register_code()
 {