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[PATCH 1/2] GDB/testsuite: Avoid timeout lowering


Hi,

 The recent change to introduce `gdb_reverse_timeout' turned out 
ineffective for board setups that set the `gdb,timeout' target variable.  
A lower `gdb,timeout' setting takes precedence and defeats the effect of 
`gdb_reverse_timeout'.  This is because the global timeout is overridden 
in gdb_test_multiple and then again in gdb_expect.

 Three timeout variables are taken into account in these two places, in 
this precedence:

1. The `gdb,timeout' target variable.

2. The caller's local `timeout' variable (upvar timeout)

3. The global `timeout' variable.

This precedence is obeyed by gdb_test_multiple strictly.  OTOH gdb_expect 
will select the higher of the two formers and will only take the latter 
into account if none of the formers is present.  However the two timeout 
selections are conceptually the same and gdb_test_multiple does its only 
for the purpose of passing it down to gdb_expect.

 Therefore I decided there is no point to keep carrying on this 
duplication and removed the sequence from gdb_test_multiple, however 
retaining the `upvar timeout' variable definition.  This way gdb_expect 
will still access gdb_test_multiple's caller `timeout' variable (if any) 
via its own `upvar timeout' reference.

 Now as to the sequence in gdb_expect.  In addition to the three variables 
described above it also takes a timeout argument into account, as the 
fourth value to choose from.  It is currently used if it is higher than 
the timeout selected from the variables as described above.

 With the timeout selection code from gdb_test_multiple gone, gone is also 
the most prominent use of this timeout argument, it's now used in a couple 
of places only, mostly within this test framework library code itself for 
preparatory commands or suchlike.  With this being the case this timeout 
selection code can be simplified as follows:

1. Among the three timeout variables, the highest is always chosen.  This 
   is so that a test case doesn't inadvertently lower a high value timeout 
   needed by slow target boards.  This is what all test cases use.

2. Any timeout argument takes precedence.  This is for special cases such 
   as within the framework library code, e.g. it doesn't make sense to 
   send `set height 0' with a timeout of 7200 seconds.  This is a local 
   command that does not interact with the target and setting a high 
   timeout here only risks a test suite run taking ages if it goes astray 
   for some reason.

3. The fallback timeout of 60s remains.

I have successfully regression tested this change on arm-linux-gnueabi and 
mips-linux-gnu targets running gdbserver on real hardware and in the 
former case also in QEMU run in the system emulation mode.

 OK to apply?

2014-07-24  Maciej W. Rozycki  <macro@codesourcery.com>

	gdb/testsuite/
	* lib/gdb.exp (gdb_test_multiple): Remove code to select the 
	timeout, don't pass one down to gdb_expect.
	(gdb_expect): Rework timeout selection.

  Maciej

gdb-test-timeout.diff
Index: gdb-fsf-trunk-quilt/gdb/testsuite/lib/gdb.exp
===================================================================
--- gdb-fsf-trunk-quilt.orig/gdb/testsuite/lib/gdb.exp	2014-07-09 22:20:42.528922292 +0100
+++ gdb-fsf-trunk-quilt/gdb/testsuite/lib/gdb.exp	2014-07-12 14:21:16.338935555 +0100
@@ -789,21 +789,6 @@ proc gdb_test_multiple { command message
 	}
     }
 
-    if [target_info exists gdb,timeout] {
-	set tmt [target_info gdb,timeout]
-    } else {
-	if [info exists timeout] {
-	    set tmt $timeout
-	} else {
-	    global timeout
-	    if [info exists timeout] {
-		set tmt $timeout
-	    } else {
-		set tmt 60
-	    }
-	}
-    }
-
     set code {
 	-re ".*A problem internal to GDB has been detected" {
 	    fail "$message (GDB internal error)"
@@ -909,7 +894,7 @@ proc gdb_test_multiple { command message
     }
 
     set result 0
-    set code [catch {gdb_expect $tmt $code} string]
+    set code [catch {gdb_expect $code} string]
     if {$code == 1} {
 	global errorInfo errorCode
 	return -code error -errorinfo $errorInfo -errorcode $errorCode $string
@@ -3070,35 +3055,27 @@ proc gdb_expect { args } {
 	set expcode $args
     }
 
+    # A timeout argument takes precedence, otherwise of all the timeouts
+    # select the largest.
+    upvar #0 timeout gtimeout
     upvar timeout timeout
-
-    if [target_info exists gdb,timeout] {
+    if [info exists atimeout] {
+	set tmt $atimeout
+    } else {
+	set tmt 0
 	if [info exists timeout] {
-	    if { $timeout < [target_info gdb,timeout] } {
-		set gtimeout [target_info gdb,timeout]
-	    } else {
-		set gtimeout $timeout
-	    }
-	} else {
-	    set gtimeout [target_info gdb,timeout]
+	    set tmt $timeout
 	}
-    }
-
-    if ![info exists gtimeout] {
-	global timeout
-	if [info exists timeout] {
-	    set gtimeout $timeout
+	if { [info exists gtimeout] && $gtimeout > $tmt } {
+	    set tmt $gtimeout
 	}
-    }
-
-    if [info exists atimeout] {
-	if { ![info exists gtimeout] || $gtimeout < $atimeout } {
-	    set gtimeout $atimeout
+	if { [target_info exists gdb,timeout]
+	     && [target_info gdb,timeout] > $tmt } {
+	    set tmt [target_info gdb,timeout]
 	}
-    } else {
-	if ![info exists gtimeout] {
+	if { $tmt == 0 } {
 	    # Eeeeew.
-	    set gtimeout 60
+	    set tmt 60
 	}
     }
 
@@ -3113,7 +3090,7 @@ proc gdb_expect { args } {
 	}
     }
     set code [catch \
-	{uplevel remote_expect host $gtimeout $expcode} string]
+	{uplevel remote_expect host $tmt $expcode} string]
     if [info exists old_val] {
 	set remote_suppress_flag $old_val
     } else {


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