[RFA/linespec] wrong line number in breakpoint location

[Joel Brobecker <brobecker at adacore dot com>]

Hello,

Consider the following situation, where we have one file containing...

    $ cat -n body.inc
         1  i = i + 1;

... we include that file from some code, like so:

    $ cat -n cat -n small.c
        [...]
        17  int
        18  next (int i)
        19  {
        20  #include "body.inc"
        21    return i;
        22  }

When trying to insert a breakpoint on line 18, for instance:

    (gdb) b small.c:18
    Breakpoint 1 at 0x40049f: file body.inc, line 18.
                                                  ^^
                                                  ||

Here, the issue is that GDB reports the breakpoint to be in file
body.inc, which is true, but with the line number that corresponding
to the user-requested location, which is not correct.

Although the simple reproducer may look slightly artificial,
the above is simply one way to reproduce the same issue observed
when trying to insert a breakpoint on a function provided in
a .h files and then subsequently inlined in a C file.

What happens is the following:

  1. We resolve the small.c:8 linespec into a symtab_and_line which
     has "small.c" and 18 as the symtab and line number.

  2. Next, we call skip_prologue_sal, which calculates the PC
     past the prologue, and updates the symtab_and_line: PC,
     but also symtab (now body.inc) and the new line (now 1).

  3. However, right after that, we do:

            /* Make sure the line matches the request, not what was
               found.  */
            intermediate_results.sals[i].line = val.line;

We should either restore both symtab and line, or leave the actual
line to match the actual symtab.  This patch chose the latter.
This introduces a few changes in a few tests, which required some
updates, but looking at those change, I believe them to be expected.

gdb/ChangeLog:

        * linespec.c (create_sals_line_offset): Remove code that preserved
        the symtab_and_line's line number.

gdb/testsuite/ChangeLog:

        * break-include.c, break-include.inc, break-include.exp: New files.
        * gdb.base/ending-run.exp: Minor adaptations due to the breakpoint's
        line number now being the actual line number where the breakpoint
        was inserted.
        * gdb.mi/mi-break.exp: Likewise.
        * gdb.mi/mi-reverse.exp: Likewise.
        * gdb.mi/mi-simplerun.exp: Ditto.

Tested on x86_64-linux. OK to commit?

Thank you,
-- 
Joel

---
 gdb/linespec.c                           |  3 ---
 gdb/testsuite/gdb.base/break-include.c   | 39 ++++++++++++++++++++++++++++++++
 gdb/testsuite/gdb.base/break-include.exp | 34 ++++++++++++++++++++++++++++
 gdb/testsuite/gdb.base/break-include.inc | 18 +++++++++++++++
 gdb/testsuite/gdb.base/ending-run.exp    |  4 ++--
 gdb/testsuite/gdb.mi/mi-break.exp        | 11 +++++----
 gdb/testsuite/gdb.mi/mi-reverse.exp      |  2 +-
 gdb/testsuite/gdb.mi/mi-simplerun.exp    |  4 ++--
 8 files changed, 103 insertions(+), 12 deletions(-)
 create mode 100644 gdb/testsuite/gdb.base/break-include.c
 create mode 100644 gdb/testsuite/gdb.base/break-include.exp
 create mode 100644 gdb/testsuite/gdb.base/break-include.inc

diff --git a/gdb/linespec.c b/gdb/linespec.c
index 8c36f2a..f81e4c1 100644
--- a/gdb/linespec.c
+++ b/gdb/linespec.c
@@ -2246,9 +2246,6 @@ create_sals_line_offset (struct linespec_state *self,
 
 	    if (self->funfirstline)
 	      skip_prologue_sal (&intermediate_results[i]);
-	    /* Make sure the line matches the request, not what was
-	       found.  */
-	    intermediate_results[i].line = val.line;
 	    add_sal_to_sals (self, &values, &intermediate_results[i],
 			     sym ? SYMBOL_NATURAL_NAME (sym) : NULL, 0);
 	  }
diff --git a/gdb/testsuite/gdb.base/break-include.c b/gdb/testsuite/gdb.base/break-include.c
new file mode 100644
index 0000000..b6e6482
--- /dev/null
+++ b/gdb/testsuite/gdb.base/break-include.c
@@ -0,0 +1,39 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2016-2017 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+int next (int i);
+
+int
+main (void)
+{
+  int result = -1;
+
+  result = next (result);
+  return result;
+}
+
+/* We implement the following function as far away from the first line
+   of this file, so as to reduce confusion between line numbers from
+   this file, and line numbers from body.inc (which only really has
+   one line of code).  */
+
+int
+next (int i)  /* break here */
+{
+#include "break-include.inc"
+  return i;
+}
diff --git a/gdb/testsuite/gdb.base/break-include.exp b/gdb/testsuite/gdb.base/break-include.exp
new file mode 100644
index 0000000..a29a221
--- /dev/null
+++ b/gdb/testsuite/gdb.base/break-include.exp
@@ -0,0 +1,34 @@
+# This testcase is part of GDB, the GNU debugger.
+
+# Copyright 2016-2017 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+standard_testfile
+
+if { [prepare_for_testing ${testfile}.exp $testfile] } {
+    return -1
+}
+
+set bp_line [gdb_get_line_number "break here" ${testfile}.c]
+set bp_line_actual [gdb_get_line_number "ANCHOR" ${testfile}.inc]
+
+gdb_test "break $testfile.c:$bp_line" \
+    ".*Breakpoint.*$testfile.inc, line $bp_line_actual\\."
+
+# Might as well verify that breaking on function "next" gives
+# the same result...
+
+gdb_test "break next" \
+    ".*Breakpoint.*$testfile.inc, line $bp_line_actual\\."
diff --git a/gdb/testsuite/gdb.base/break-include.inc b/gdb/testsuite/gdb.base/break-include.inc
new file mode 100644
index 0000000..4573672
--- /dev/null
+++ b/gdb/testsuite/gdb.base/break-include.inc
@@ -0,0 +1,18 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2016-2017 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+i = i + 1;  /* ANCHOR */
diff --git a/gdb/testsuite/gdb.base/ending-run.exp b/gdb/testsuite/gdb.base/ending-run.exp
index 42cbf23..e2b1ccc 100644
--- a/gdb/testsuite/gdb.base/ending-run.exp
+++ b/gdb/testsuite/gdb.base/ending-run.exp
@@ -68,14 +68,14 @@ gdb_test_multiple "i b" "cleared bp at line before routine" {
 gdb_test "b ending-run.c:1" ".*Breakpoint.*4.*"
 gdb_test "b ending-run.c:$break1_line" ".*Note.*also.*Breakpoint.*5.*" "b ending-run.c:$break1_line, two"
 gdb_test "cle ending-run.c:$break1_line" \
-	".*Deleted breakpoint 5.*" "Cleared 2 by line"
+	".*Deleted breakpoints 4 5.*" "Cleared 2 by line"
 
 gdb_test_multiple "info line ending-run.c:$break1_line" "" {
     -re ".*address (0x\[0-9a-fA-F]*).*$gdb_prompt $" {
         set line_nine $expect_out(1,string)
         gdb_test "b ending-run.c:$break1_line" ".*Breakpoint 6.*ending-run.c, line $break1_line.*"
         gdb_test "b *$line_nine" ".*Note.*also.*Breakpoint 7.*" "breakpoint 7 at *ending-run.c:$break1_line"
-        gdb_test "cle" ".*Deleted breakpoints 4 6 7.*" "clear 2 by default"
+        gdb_test "cle" ".*Deleted breakpoints 6 7.*" "clear 2 by default"
     }
     -re ".*$gdb_prompt $" {
         fail "need to fix test for new compile outcome"
diff --git a/gdb/testsuite/gdb.mi/mi-break.exp b/gdb/testsuite/gdb.mi/mi-break.exp
index 41a48a1..0005f7e 100644
--- a/gdb/testsuite/gdb.mi/mi-break.exp
+++ b/gdb/testsuite/gdb.mi/mi-break.exp
@@ -49,7 +49,9 @@ set fullname "fullname=\"${fullname_syntax}${srcfile}\""
 proc test_tbreak_creation_and_listing {} {
     global srcfile
     global line_callee4_head
+    global line_callee4_body
     global line_callee3_head
+    global line_callee3_body
     global line_callee2_body
     global line_main_body
 
@@ -75,7 +77,7 @@ proc test_tbreak_creation_and_listing {} {
     lappend bps [mi_create_breakpoint "-t basics.c:$line_callee3_head" \
 		     "insert temp breakpoint at basics.c:\$line_callee3_head" \
 		     -number 3 -disp del -func callee3 -file ".*basics.c" \
-		     -line $line_callee3_head]
+		     -line $line_callee3_body]
 
     # Getting the quoting right is tricky.
     # That is "\"<file>\":$line_callee4_head"
@@ -83,7 +85,7 @@ proc test_tbreak_creation_and_listing {} {
 		     "-t \"\\\"${srcfile}\\\":$line_callee4_head\"" \
 		     "insert temp breakpoint at \"<fullfilename>\":\$line_callee4_head" \
 		     -number 4 -disp del -func callee4 -file ".*basics.c" \
-		     -line $line_callee4_head]
+		     -line $line_callee4_body]
 
     mi_gdb_test "666-break-list" \
 	"666\\\^done,[mi_make_breakpoint_table $bps]" \
@@ -319,6 +321,7 @@ proc test_breakpoint_commands {} {
 proc test_explicit_breakpoints {} {
     global srcfile
     global line_callee3_head line_callee4_head
+    global line_callee3_body line_callee4_body
     global line_callee2_body line_main_body
 
     mi_delete_breakpoints
@@ -349,13 +352,13 @@ proc test_explicit_breakpoints {} {
     lappend bps \
 	[mi_create_breakpoint "-t --source $srcfile --line $line_callee3_head" \
 	     "insert temp explicit breakpoint at $srcfile:$line_callee3_head" \
-	     -func callee3 -file ".*$srcfile" -line $line_callee3_head]
+	     -func callee3 -file ".*$srcfile" -line $line_callee3_body]
 
     lappend bps \
 	[mi_create_breakpoint \
 	     "-t --source \"$srcfile\" --line  $line_callee4_head" \
 	     "insert temp explicit breakpoint at \"$srcfile\":$line_callee4_head" \
-	     -func callee4 -file ".*$srcfile" -line $line_callee4_head]
+	     -func callee4 -file ".*$srcfile" -line $line_callee4_body]
 
     mi_gdb_test "-break-list" "\\^done,[mi_make_breakpoint_table $bps]" \
 	"list of explicit breakpoints"
diff --git a/gdb/testsuite/gdb.mi/mi-reverse.exp b/gdb/testsuite/gdb.mi/mi-reverse.exp
index 448a9a3..30b96f3 100644
--- a/gdb/testsuite/gdb.mi/mi-reverse.exp
+++ b/gdb/testsuite/gdb.mi/mi-reverse.exp
@@ -153,7 +153,7 @@ proc test_controlled_execution_reverse {} {
     mi_create_breakpoint "-t basics.c:$line_callee3_head" \
 	"insert temp breakpoint at basics.c:$line_callee3_head" \
 	-number 3 -disp del -func callee3 -file ".*basics.c" \
-	-line $line_callee3_head
+	-line $line_callee3_body
 
     mi_execute_to "exec-continue --reverse" \
         "breakpoint-hit" "callee3" \
diff --git a/gdb/testsuite/gdb.mi/mi-simplerun.exp b/gdb/testsuite/gdb.mi/mi-simplerun.exp
index db75f4d..e6b5a4f 100644
--- a/gdb/testsuite/gdb.mi/mi-simplerun.exp
+++ b/gdb/testsuite/gdb.mi/mi-simplerun.exp
@@ -78,13 +78,13 @@ proc test_breakpoints_creation_and_listing {} {
     lappend bps [mi_create_breakpoint "basics.c:$line_callee3_head" \
 		     "insert breakpoint at basics.c:\$line_callee3_head" \
 		     -number 3 -func callee3 -file ".*basics.c" \
-		     -line $line_callee3_head]
+		     -line $line_callee3_body]
 
     lappend bps [mi_create_breakpoint \
 		     "\"\\\"${srcfile}\\\":$line_callee4_head\"" \
 		     "insert breakpoint at \"<fullfilename>\":\$line_callee4_head" \
 		     -number 4 -func callee4 -file ".*basics.c" \
-		     -line $line_callee4_head]
+		     -line $line_callee4_body]
 
     mi_gdb_test "204-break-list" \
 	"204\\^done,[mi_make_breakpoint_table $bps]" \
-- 
2.1.4