[PATCH 6/6] gdb/tui: Link source and assembler scrolling .... again

[Andrew Burgess <andrew dot burgess at embecosm dot com>]

Until recently when the source window was scrolled the assembler
window would scroll in sync - keeping the disassembly for the current
line in view.

This was broken in commit:

  commit b4b49dcbff6b437fa8b4e2fc0c3f27b457f11310
  Date:   Wed Nov 13 16:47:58 2019 -0700

      Don't call tui_show_source from tui_ui_out

This commit restores the synchronised scrolling and also maintains the
horizontal scroll within the source view when it is vertically
scrolled, something that was broken before.

This commit does not mean that scrolling the assembler view scrolls
the source view.  The connection this way never existed, though maybe
it should, but I'll leave adding this feature for a separate commit.

gdb/ChangeLog:

	* tui/tui-source.c (tui_source_window::do_scroll_vertical): Update
	all source windows, and maintain horizontal scroll status while
	doing so.

gdb/testsuite/ChangeLog:

	* gdb.tui/basic.exp: Add more scrolling tests.

Change-Id: I250114a3bc670040a6a759d41905776771b2f818
---
 gdb/ChangeLog                   |  6 ++++++
 gdb/testsuite/ChangeLog         |  4 ++++
 gdb/testsuite/gdb.tui/basic.exp | 27 +++++++++++++++++++++++++++
 gdb/tui/tui-source.c            |  4 +++-
 4 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/gdb/testsuite/gdb.tui/basic.exp b/gdb/testsuite/gdb.tui/basic.exp
index be822f8a915..34e60384c4e 100644
--- a/gdb/testsuite/gdb.tui/basic.exp
+++ b/gdb/testsuite/gdb.tui/basic.exp
@@ -48,6 +48,33 @@ if {[Term::wait_for [string_to_regexp $line]] \
     fail "scroll up"
 }
 
+# Check the horizontal scrolling.  First confirm that 'main ()' is
+# where we expect it to be.  This relies on the current way we
+# position source code on the screen, which might change in the
+# future.  The important part of this test is detecting the left/right
+# scrolling, not which line main is actually on.
+set line_num 6
+set line [Term::get_line $line_num]
+gdb_assert {[regexp -- "19\[\\t \]+main \\(\\)" $line]} \
+    "check main is where we expect on the screen"
+set regexp "19\[\\t \]+ain \\(\\)"
+# Send a right arrow.
+send_gdb "\033\[C"
+if {[Term::wait_for $regexp]} {
+    pass "scroll right"
+} else {
+    fail "scroll right"
+}
+set line [Term::get_line $line_num]
+# Send a down arrow.
+send_gdb "\033\[B"
+if {[Term::wait_for $regexp] \
+	&& [Term::get_line [expr {$line_num - 1}]] == $line} {
+    pass "scroll down"
+} else {
+    fail "scroll down"
+}
+
 Term::check_box "source box" 0 0 80 15
 
 Term::command "layout asm"
diff --git a/gdb/tui/tui-source.c b/gdb/tui/tui-source.c
index 13f2dc7cfe1..912eaa45440 100644
--- a/gdb/tui/tui-source.c
+++ b/gdb/tui/tui-source.c
@@ -158,7 +158,9 @@ tui_source_window::do_scroll_vertical (int num_to_scroll)
 	line_no = 1;
 
       cursal.line = line_no;
-      update_source_window (arch, cursal);
+      find_line_pc (cursal.symtab, cursal.line, &cursal.pc);
+      for (struct tui_source_window_base *win_info : tui_source_windows ())
+	win_info->update_source_window_as_is (arch, cursal);
     }
 }
 
-- 
2.14.5