[RFA] Add test for use of "<block>::<variable>" syntax for locals in watch.

[Paul Hilfinger <Hilfinger@adacore.com>]

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This patch augments watchpoint.c to check the BLOCK::VARIABLE syntax
in watched expressions when it refers to local variables (and also to
fix a small bug I found in the existing version of the file).
However, as things stand, the test is not particularly stringent,
since the relevant part is restricted to the hppa, sparc SunOS, and
m32r platforms.  I modified the restriction temporarily to check that
the test now works on i686 Linux, but did not make that a part of the
patch, since I think that someone who knows more about the reason for
the restriction ought to decide whether it is time to remove it.

First, fix a technical problem with the function recurser.  The test sets a
watch on local_x at a point where its value is technically undefined.  The
test is written assuming that the value is not initially 2, but nothing in the
C standard guarantees that.

Second, augment the existing test for variables in recursive calls to check an
equivalent expression that explicitly sets the scope of the local variable
being tracked.

Paul N. Hilfinger
(Hilfinger@adacore.com)


2012-01-07  Paul Hilfinger  <brobecker@adacore.com>

* gdb/testsuite/gdb.base/watchpoint.c (recurser): Initialize local_x.
  (main) Repeat recurser call.
* gdb/testsuite/gdb.base/watchpoint.exp: Check that 'watch recurser::local_x' is
  equivalent to 'local_x'.
---
 gdb/testsuite/gdb.base/watchpoint.c   |    8 +++++++-
 gdb/testsuite/gdb.base/watchpoint.exp |   14 ++++++++++++++
 2 files changed, 21 insertions(+), 1 deletions(-)


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diff --git a/gdb/testsuite/gdb.base/watchpoint.c b/gdb/testsuite/gdb.base/watchpoint.c
index 50f0a83..88c110f 100644
--- a/gdb/testsuite/gdb.base/watchpoint.c
+++ b/gdb/testsuite/gdb.base/watchpoint.c
@@ -80,7 +80,7 @@ void recurser (int  x)
 void recurser (x) int  x;
 #endif
 {
-  int  local_x;
+  int  local_x = 0;
 
   if (x > 0)
     recurser (x-1);
@@ -232,6 +232,12 @@ int main ()
   marker6 ();
   recurser (2);
 
+  /* This invocation is used for watches of a local variable with explicitly
+     specified scope when recursion happens.
+     */
+  marker6 ();
+  recurser (2);
+
   marker6 ();
 
   func3 ();
diff --git a/gdb/testsuite/gdb.base/watchpoint.exp b/gdb/testsuite/gdb.base/watchpoint.exp
index f321de5..1860368 100644
--- a/gdb/testsuite/gdb.base/watchpoint.exp
+++ b/gdb/testsuite/gdb.base/watchpoint.exp
@@ -580,6 +580,7 @@ proc test_complex_watchpoint {} {
         #
         gdb_test "tbreak recurser" ".*breakpoint.*"
         gdb_test "cont" "Continuing.*recurser.*"
+        gdb_test "next" "if \\(x > 0.*" "next past local_x initialization"
         gdb_test "watch local_x" ".*\[Ww\]atchpoint \[0-9\]*: local_x" \
                  "set local watch in recursive call"
         gdb_test "cont" "Continuing.*\[Ww\]atchpoint .*: local_x.*New value = 2.*" \
@@ -587,6 +588,19 @@ proc test_complex_watchpoint {} {
         gdb_test "cont" "Continuing.*\[Ww\]atchpoint .* deleted because the program has left the block in.*which its expression is valid.*" \
                  "self-delete local watch in recursive call"
 
+        # Repeat the preceding test, but this time use "recurser::local_x" as
+        # the variable to track.
+        gdb_test "cont" "Continuing.*marker6.*"
+        gdb_test "tbreak recurser" ".*breakpoint.*"
+        gdb_test "cont" "Continuing.*recurser.*"
+        gdb_test "next" "if \\(x > 0.*" "next past local_x initialization"
+        gdb_test "watch recurser::local_x" ".*\[Ww\]atchpoint \[0-9\]*: recurser::local_x" \
+                 "set local watch in recursive call with explicit scope"
+        gdb_test "cont" "Continuing.*\[Ww\]atchpoint .*: recurser::local_x.*New value = 2.*" \
+                 "trigger local watch with explicit scope in recursive call"
+        gdb_test "cont" "Continuing.*\[Ww\]atchpoint .* deleted because the program has left the block in.*which its expression is valid.*" \
+                 "self-delete local watch with explicit scope in recursive call (2)"
+
 	# Disable everything so we can finish the program at full speed
 	gdb_test_no_output "disable" "disable in test_complex_watchpoint"