[PATCH 3/3] Fix bug in ada_print_floating

[Tom Tromey <tromey@adacore.com>]

ada_print_floating rewrites a floating-point string representation to
conform to Ada syntax.  However, if you managed to get a floating
point error, you might see:

    (gdb) print whatever
    $2 = <invalid float valu.0e>

What's happening here is that ada_print_floating doesn't recognize
this error case, and proceeds to modify the error text.

This patch fixes this problem.
---
 gdb/ada-valprint.c                   | 7 +++++++
 gdb/testsuite/gdb.ada/float-bits.exp | 3 +++
 2 files changed, 10 insertions(+)

diff --git a/gdb/ada-valprint.c b/gdb/ada-valprint.c
index bf95719f040..e113088491c 100644
--- a/gdb/ada-valprint.c
+++ b/gdb/ada-valprint.c
@@ -314,6 +314,13 @@ ada_print_floating (const gdb_byte *valaddr, struct type *type,
   std::string s = tmp_stream.release ();
   size_t skip_count = 0;
 
+  /* Don't try to modify a result representing an error.  */
+  if (s[0] == '<')
+    {
+      fputs_filtered (s.c_str (), stream);
+      return;
+    }
+
   /* Modify for Ada rules.  */
 
   size_t pos = s.find ("inf");
diff --git a/gdb/testsuite/gdb.ada/float-bits.exp b/gdb/testsuite/gdb.ada/float-bits.exp
index 61db5f325ad..c98afb53c06 100644
--- a/gdb/testsuite/gdb.ada/float-bits.exp
+++ b/gdb/testsuite/gdb.ada/float-bits.exp
@@ -48,3 +48,6 @@ gdb_test "print val_long_double := 16llf#7FFFF7FF4054A56FA5B99019A5C8#" \
     " = 5.0e\\+25"
 gdb_test "print val_long_double" " = 5.0e\\+25" \
     "print val_long_double after assignment"
+
+gdb_test "print 16llf#a56fa5b99019a5c800007ffff7ff4054#" \
+    " = <invalid float value>"
-- 
2.31.1