[gdb/testsuite] Fix gdb.base/float128.exp with --with-mpfr=no

When configuring gdb using --with-mpfr=no and running test-case
gdb.base/float128.exp, we run into:
...
FAIL: gdb.base/float128.exp: print large128 (GDB may be missing MPFR support!)
...

Fix this by detecting that gdb was build without mpfr using the show
configuration command, and changing the FAIL into UNSUPPORTED.

Tested on x86_64-linux.

gdb/testsuite/ChangeLog:

2020-12-11  Tom de Vries  <tdevries@suse.de>

	PR testsuite/26954
	* gdb.base/float128.exp: Detect and handle no mpfr support.

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 07e206a1a5ccdf5cdc1b76054bcdbd69a735a03b..5b89bcd5d85b4829291fe4ba251c8b65c0e27374 100644 (file)
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-12-11  Tom de Vries  <tdevries@suse.de>
+
+       PR testsuite/26954
+       * gdb.base/float128.exp: Detect and handle no mpfr support.
+
 2020-12-10  Simon Marchi  <simon.marchi@efficios.com>
 
        PR gdb/24694

diff --git a/gdb/testsuite/gdb.base/float128.exp b/gdb/testsuite/gdb.base/float128.exp
index 40babcadc12df791ec68ea4e3f5898f74eeafb53..6fe479bb94a8ff019640147199a2cec1b0a4959f 100644 (file)
--- a/gdb/testsuite/gdb.base/float128.exp
+++ b/gdb/testsuite/gdb.base/float128.exp
@@ -74,6 +74,16 @@ gdb_test_multiple "set var f128=20.375l" "$test" {
 gdb_test "print ld" ".* = 10\\.375.*" "the value of ld is changed to 10.375"
 gdb_test "print f128" ".* = 20\\.375.*" "the value of f128 is changed to 20.375"
 
+set mpfr_supported -1
+gdb_test_multiple "show configuration" "" {
+    -wrap -re "--with-mpfr\r\n.*" {
+       set mpfr_supported 1
+    }
+    -wrap -re "--without-mpfr\r\n.*" {
+       set mpfr_supported 0
+    }
+}
+
 # Test that we can correctly handle the largest IEEE-128 value
 # Note: If we get "inf" instead of the correct result, we may have run into
 # an internal overflow.  This typically happens on host platforms without
@@ -84,7 +94,17 @@ gdb_test_multiple "print large128" "$test" {
        pass "$test"
     }
     -re ".* = inf.*$gdb_prompt $" {
-       fail "$test (GDB may be missing MPFR support!)"
+       if { $mpfr_supported == 0 } {
+          # If the host platform has native 128-bit float support (as is
+          # the case for some versions of s390 and powerpc), the
+          # "print large128" test should be passing, even without MPFR
+          # support.  So, in those cases we should have fail here rather than
+          # unsupported.  However, given that we don't have a way to readily
+          # test for this, we fall back to unsupported.
+          unsupported "$test (Missing MPFR support)"
+       } else {
+           fail $test
+       }
     }
     -re ".*$gdb_prompt $" {
        fail "$test"