[binutils-gdb] [gdb/testsuite] Fix error handling in gdb_file_cmd

[binutils-gdb] [gdb/testsuite] Fix error handling in gdb_file_cmd

[Tom de Vries]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=95146b5da22532c6688e457adb48fecbceb194b3

commit 95146b5da22532c6688e457adb48fecbceb194b3
Author: Tom de Vries <tdevries@suse.de>
Date:   Thu Jun 4 16:33:55 2020 +0200

    [gdb/testsuite] Fix error handling in gdb_file_cmd
    
    Consider a gdb_load patch to call the gdb_file_cmd twice:
    ...
     proc gdb_load { arg } {
         if { $arg != "" } {
    +       set res [gdb_file_cmd $arg]
    +       if { $res != 0 } {
    +           return $res
    +       }
            return [gdb_file_cmd $arg]
         }
         return 0
     }
    ...
    
    When running test-case gdb.base/index-cache.exp, we run into:
    ...
    ERROR: Couldn't load outputs/gdb.base/index-cache/index-cache, other program \
      already loaded (timeout).
    FAIL: gdb.base/index-cache.exp: test_cache_enabled_miss: check index-cache \
      stats (GDB internal error)
    ERROR: Couldn't load outputs/gdb.base/index-cache/index-cache, other program \
      already loaded (timeout).
    ...
    
    The first timeout in more detail:
    ...
    (gdb) file outputs/gdb.base/index-cache/index-cache^M
    Load new symbol table from "index-cache"? (y or n) y^M
    Reading symbols from index-cache...^M
    src/gdb/dwarf2/read.c:2540: internal-error: \
      void create_cus_from_index(dwarf2_per_bfd*, const gdb_byte*, offset_type, \
                                 const gdb_byte*, offset_type): \
      Assertion `per_bfd->all_comp_units.empty ()' failed.^M
    A problem internal to GDB has been detected,^M
    further debugging may prove unreliable.^M
    Quit this debugging session? (y or n) ERROR: Couldn't load index-cache, \
      other program already loaded (timeout).
    ...
    
    Proc gdb_file_cmd has a gdb_expect handling the result of the file command,
    and if the result is a "Load new symbol table from index-cache? (y or n) "
    prompt, it sends a "y" and enters in a nested gdb_expect to handle the
    result.
    
    The first gdb_expect contains code to handle "A problem internal to GDB has
    been detected", but the second one doesn't, which causes the timeout.
    
    Fix this by removing the nested gdb_expect, and using exp_continue instead,
    such that we have instead:
    ...
    ERROR: Couldn't load outputs/gdb.base/index-cache/index-cache -- with new \
      symbol table into gdb (GDB internal error).
    ERROR: Couldn't load outputs/gdb.base/index-cache/index-cache -- with new \
      symbol table into gdb (GDB internal error).
    ...
    
    Tested on x86_64-linux.
    
    gdb/testsuite/ChangeLog:
    
    2020-06-04  Tom de Vries  <tdevries@suse.de>
    
            * lib/gdb.exp (gdb_file_cmd): Replace incomplete gdb_expect by
            exp_continue.

Diff:
---
 gdb/testsuite/ChangeLog   |  5 +++++
 gdb/testsuite/lib/gdb.exp | 23 ++++++++---------------
 2 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index ab9443eceb7..9d979382c36 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-06-04  Tom de Vries  <tdevries@suse.de>
+
+	* lib/gdb.exp (gdb_file_cmd): Replace incomplete gdb_expect by
+	exp_continue.
+
 2020-06-04  Tom de Vries  <tdevries@suse.de>
 
 	* lib/gdb.exp (gdb_file_cmd): Use perror instead of fail.
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 63a9e3da535..3cdaefaa9cd 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -1761,6 +1761,7 @@ proc gdb_file_cmd { arg } {
     }
 
     send_gdb "file $arg\n"
+    set new_symbol_table 0
     gdb_expect 120 {
 	-re "Reading symbols from.*LZMA support was disabled.*$gdb_prompt $" {
 	    verbose "\t\tLoaded $arg into $GDB; .gnu_debugdata found but no LZMA available"
@@ -1778,22 +1779,14 @@ proc gdb_file_cmd { arg } {
 	    return 0
         }
         -re "Load new symbol table from \".*\".*y or n. $" {
+	    if { $new_symbol_table > 0 } {
+		perror "Couldn't load $arg, interactive prompt loop detected."
+		return -1
+	    }
             send_gdb "y\n" answer
-            gdb_expect 120 {
-                -re "Reading symbols from.*$gdb_prompt $" {
-                    verbose "\t\tLoaded $arg with new symbol table into $GDB"
-		    set gdb_file_cmd_debug_info "debug"
-		    return 0
-                }
-                timeout {
-                    perror "Couldn't load $arg, other program already loaded (timeout)."
-		    return -1
-                }
-		eof {
-		    perror "Couldn't load $arg, other program already loaded (eof)."
-		    return -1
-		}
-            }
+	    incr new_symbol_table
+	    set arg "$arg -- with new symbol table"
+	    exp_continue
 	}
         -re "No such file or directory.*$gdb_prompt $" {
             perror "($arg) No such file or directory"