Make ctxobj.exp and print-file-var.exp work on all platforms.

This patch adjusts the testing strategy used in a couple of testcases
where we are trying to print the value of a global variable defined
at multiple locations.  The problem is that the actual value depends
on the platform.  So instead of hard-coding the expected value in
the testcase script, we use local variables (in the inferior) holding
the correct value, and we compare the global variable's value with
the local variable's value.

gdb/testsuite/ChangeLog:

        * gdb.base/ctxobj-f.c (GET_VERSION): Introduce local variable
        and add comment.
        * gdb.base/ctxobj-m.c (main): Rewrite, and add comment.
        * gdb.base/ctxobj.exp: Insert breakpoint in ctxobj-f.c using
        "STOP" marker.  Adjust testing strategy to make it work on
        all targets.

        * gdb.base/print-file-var-main.c (main): Rewrite using local
        variables and adjust get_version_2's return value check.
        Add small comment.
        * gdb.base/print-file-var.exp: Insert breakpoint using "STOP"
        marker.  Adjust testing strategy to make it work on all targets.

gdb/testsuite/ChangeLog

@@ -1,3 +1,18 @@
+2012-06-05  Joel Brobecker  <brobecker@adacore.com>
+
+	* gdb.base/ctxobj-f.c (GET_VERSION): Introduce local variable
+	and add comment.
+	* gdb.base/ctxobj-m.c (main): Rewrite, and add comment.
+	* gdb.base/ctxobj.exp: Insert breakpoint in ctxobj-f.c using
+	"STOP" marker.  Adjust testing strategy to make it work on
+	all targets.
+
+	* gdb.base/print-file-var-main.c (main): Rewrite using local
+	variables and adjust get_version_2's return value check.
+	Add small comment.
+	* gdb.base/print-file-var.exp: Insert breakpoint using "STOP"
+	marker.  Adjust testing strategy to make it work on all targets.
+
 2012-06-05  Joel Brobecker  <brobecker@adacore.com>
 
 	* gdb.ada/bad-task-bp-keyword: New testcase.

gdb/testsuite/gdb.base/ctxobj-f.c

@@ -23,5 +23,10 @@ extern int this_version_num;
 int
 GET_VERSION (void)
 {
-  return this_version_num;
+  int v = this_version_num;
+
+  if (v > 999)
+    v = 999;
+
+  return v;  /* STOP */
 }

gdb/testsuite/gdb.base/ctxobj-m.c

@@ -20,10 +20,16 @@ extern int get_version_2 (void);
 int
 main (void)
 {
-  if (get_version_1 () != 104)
+  int v1 = get_version_1 ();
+  int v2 = get_version_2 ();
+
+  if (v1 != 104)
     return 1;
 
-  if (get_version_2 () != 203)
+  /* The value returned by get_version_2 depends on the target.
+     On GNU/Linux, for instance, it should return 104.  But on
+     x86-windows, for instance, it will return 203.  */
+  if (v2 != 104 && v2 != 203)
     return 2;
 
   return 0;

gdb/testsuite/gdb.base/ctxobj.exp

@@ -57,38 +57,53 @@ if ![runto_main] {
     return -1
 }
 
-gdb_breakpoint "get_version_1"
+set bp_location [gdb_get_line_number "STOP" "ctxobj-f.c"]
+gdb_test "break ctxobj-f.c:$bp_location" \
+         "Breakpoint \[0-9\]+ at 0x\[0-9a-fA-F\]+: .*" \
+         "break in get_version functions"
+
 gdb_test "continue" \
          "Breakpoint $decimal, get_version_1 \\(\\).*" \
          "continue to get_version_1"
 
 # Try printing "this_version_num".  There are two global variables
-# with that name, but we should pick the one in the shared library
-# we are currently debugging.  We will know we picked the correct one
-# if the value printed is 104.  The first print test verifies that
-# we're doing things right when the partial symtab hasn't been
-# expanded.  And the second print test will do the same, but after
-# the partial symtab has been expanded.
+# with that name, and some systems such as GNU/Linux merge them
+# into one single entity, while some other systems such as Windows
+# keep them separate.  In the first situation, we have to verify
+# that GDB does not randomly select the wrong instance.  And in
+# the second case, we have to verify that GDB prints the value
+# of the instance from the current debugging context (the shared
+# library currently being debugged).
+#
+# We perform two tests: The first print test verifies that we are
+# doing things right when the partial symtab hasn't been expanded.
+# And the second print test will do the same, but after the partial
+# symtab has been expanded.
+#
+# To avoid adding target-specific code in this testcase, the program
+# sets a local variable named 'v' with the value of the global
+# variable 'this_version_number'.  This allows us to compare the value
+# that GDB thinks 'this_version_num' has, against the actual value
+# seen by the program itself.
 
-gdb_test "print this_version_num" \
-         " = 104" \
+gdb_test "print this_version_num == v" \
+         " = 1" \
         "print libctxobj1's this_version_num from partial symtab"
 
-gdb_test "print this_version_num" \
-         " = 104" \
+gdb_test "print this_version_num == v" \
+         " = 1" \
         "print libctxobj1's this_version_num from symtab"
 
 # Do the same, but from get_version_2.
 
-gdb_breakpoint "get_version_2"
 gdb_test "continue" \
          "Breakpoint $decimal, get_version_2 \\(\\).*" \
          "continue to get_version_2"
 
-gdb_test "print this_version_num" \
-         " = 203" \
+gdb_test "print this_version_num == v" \
+         " = 1" \
         "print libctxobj2's this_version_num from partial symtab"
 
-gdb_test "print this_version_num" \
-         " = 203" \
+gdb_test "print this_version_num == v" \
+         " = 1" \
         "print libctxobj2's this_version_num from symtab"

gdb/testsuite/gdb.base/print-file-var-main.c

@@ -20,10 +20,15 @@ extern int get_version_2 (void);
 int
 main (void)
 {
-  if (get_version_1 () != 104)
+  int v1 = get_version_1 ();
+  int v2 = get_version_2 ();
+
+  if (v1 != 104)  /* STOP */
     return 1;
-  if (get_version_2 () != 104)
+  /* The value returned by get_version_2 depends on the target system.  */
+  if (v2 != 104 || v2 != 203)
     return 2;
+
   return 0;
 }
 

gdb/testsuite/gdb.base/print-file-var.exp

@@ -48,8 +48,39 @@ if ![runto_main] {
     return -1
 }
 
-gdb_test "print 'print-file-var-lib1.c'::this_version_id" \
-         " = 104"
+# Try printing "this_version_num" qualified with the name of the file
+# where the variables are defined.  There are two global variables
+# with that name, and some systems such as GNU/Linux merge them
+# into one single entity, while some other systems such as Windows
+# keep them separate.  In the first situation, we have to verify
+# that GDB does not randomly select the wrong instance, even when
+# a specific filename is used to qualified the lookup.  And in the
+# second case, we have to verify that GDB does select the instance
+# defined in the given filename.
+#
+# To avoid adding target-specific code in this testcase, the program
+# sets two local variable named 'v1' and 'v2' with the value of
+# our global variables.  This allows us to compare the value that
+# GDB returns for each query against the actual value seen by
+# the program itself.
 
-gdb_test "print 'print-file-var-lib2.c'::this_version_id" \
-         " = 203"
+# Get past the initialization of variables 'v1' and 'v2'.
+
+set bp_location \
+    [gdb_get_line_number "STOP" "${executable}.c"]
+gdb_test "break $executable.c:$bp_location" \
+         "Breakpoint \[0-9\]+ at 0x\[0-9a-fA-F\]+: .*" \
+         "breapoint past v1 & v2 initialization"
+
+gdb_test "continue" \
+         "Breakpoint \[0-9\]+, main \\(\\) at.*" \
+         "continue to STOP marker"
+
+# Now check the value of this_version_id in both print-file-var-lib1.c
+# and print-file-var-lib2.c.
+
+gdb_test "print 'print-file-var-lib1.c'::this_version_id == v1" \
+         " = 1"
+
+gdb_test "print 'print-file-var-lib2.c'::this_version_id == v2" \
+         " = 1"