[binutils-gdb] [gdb/tui] Fix len_without_escapes in tui-disasm.c

[Tom de Vries]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d811a7cf74fa8523f67a13c0527b27f4954e9ae1

commit d811a7cf74fa8523f67a13c0527b27f4954e9ae1
Author: Tom de Vries <tdevries@suse.de>
Date:   Tue Apr 6 10:40:11 2021 +0200

    [gdb/tui] Fix len_without_escapes in tui-disasm.c
    
    On openSUSE Tumbleweed I run into:
    ...
    FAIL: gdb.tui/basic.exp: asm window shows main
    ERROR: invalid command name "_csi_L"
    ...
    
    Using a minimal example, we get:
    ...
    $ gdb -q outputs/gdb.tui/basic/basic -ex "tui enable" -ex "layout asm"
    <TUI output>
    src/gdb/ui-style.c:243: internal-error: bool \
      ui_file_style::parse(const char*, size_t*): Assertion `match == 0' failed.
    ...
    
    The problem is in len_without_escapes, where we detect the start of an escape
    sequence, but then pass ptr to style.parse while ptr no longer points to the
    escape due to the ptr++ in the while condition:
    ...
      while ((c = *ptr++) != '\0')
         {
          if (c == '\033')
            {
              ui_file_style style;
              size_t n_read;
              if (style.parse (ptr, &n_read))
    ...
    
    Fix this by removing the ++ in the while condition, and adding ptr++ in the
    loop body where appropriate.
    
    Tested on x86_64-linux.
    
    gdb/ChangeLog:
    
    2021-04-06  Tom de Vries  <tdevries@suse.de>
    
            PR tui/27680
            * tui/tui-disasm.c (len_without_escapes): Pass ptr pointing at escape
            to style.parse.

Diff:
---
 gdb/ChangeLog        | 6 ++++++
 gdb/tui/tui-disasm.c | 7 +++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 281c567a8d7..0abd3dd6df1 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2021-04-06  Tom de Vries  <tdevries@suse.de>
+
+	PR tui/27680
+	* tui/tui-disasm.c (len_without_escapes): Pass ptr pointing at escape
+	to style.parse.
+
 2021-04-04  Simon Marchi  <simon.marchi@polymtl.ca>
 
 	* avr-tdep.c (avr_frame_unwind_cache): Use
diff --git a/gdb/tui/tui-disasm.c b/gdb/tui/tui-disasm.c
index 65b300cb008..163552aede4 100644
--- a/gdb/tui/tui-disasm.c
+++ b/gdb/tui/tui-disasm.c
@@ -61,7 +61,7 @@ len_without_escapes (const std::string &str)
   const char *ptr = str.c_str ();
   char c;
 
-  while ((c = *ptr++) != '\0')
+  while ((c = *ptr) != '\0')
     {
       if (c == '\033')
 	{
@@ -77,7 +77,10 @@ len_without_escapes (const std::string &str)
 	    }
 	}
       else
-	++len;
+	{
+	  ++len;
+	  ++ptr;
+	}
     }
   return len;
 }