[binutils-gdb] Make gdb.ada/float-bits.exp more generic

[binutils-gdb] Make gdb.ada/float-bits.exp more generic

[Luis Machado]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d1fb8316b09ea35edaaa9a93e32a3adba51aef46

commit d1fb8316b09ea35edaaa9a93e32a3adba51aef46
Author: Luis Machado <luis.machado@arm.com>
Date:   Tue Apr 26 11:56:07 2022 +0100

    Make gdb.ada/float-bits.exp more generic
    
    There are assumptions in the test about the long double format
    being used. While the results are OK for i387 128-bit long doubles, it
    is not correct for IEEE quad 128-bit long doubles.
    
    Also, depending on the target (64-bit/32-bit), long doubles may not
    be available at all. And it may be the case that the compiler for a 64-bit
    target doesn't support 128-bit long doubles, but GDB might still support it
    internally.
    
    Lastly, not every long double format has invalid values. Some formats
    consider all values as valid floating point numbers.
    
    These divergences cause the following FAIL's on aarch64/arm:
    
    FAIL: gdb.ada/float-bits.exp: print val_long_double
    FAIL: gdb.ada/float-bits.exp: print val_long_double after assignment
    
    With the above in mind, extend the test a little so it behaves well on
    different architectures and so it works with different long double
    formats.
    
    Main changes:
    
    - Use long double values appropriate for the long double format.
    - Test long double assignment to compiler-generated long
      double variables.
    - Test long double assignment to GDB internal variables.
    
    Tested on x86_64 (16 PASS), i686 (16 PASS), aarch64 (12 PASS) and arm (9 PASS).

Diff:
---
 gdb/testsuite/gdb.ada/float-bits.exp | 87 ++++++++++++++++++++++++++++--------
 1 file changed, 68 insertions(+), 19 deletions(-)

diff --git a/gdb/testsuite/gdb.ada/float-bits.exp b/gdb/testsuite/gdb.ada/float-bits.exp
index 4ca8dbf88e5..55a0566580c 100644
--- a/gdb/testsuite/gdb.ada/float-bits.exp
+++ b/gdb/testsuite/gdb.ada/float-bits.exp
@@ -25,6 +25,27 @@ if {[gdb_compile_ada "${srcfile}" "${binfile}" executable {debug}] != ""} {
     return -1
 }
 
+# Given a floating point EXPRESSION, return the size of the result.
+
+proc float_size { expression } {
+
+    set size 0
+    gdb_test_multiple "ptype ${expression}" "" {
+	-re -wrap "<16-byte float>" {
+	    set size 16
+	}
+	-re -wrap "<12-byte float>" {
+	    set size 12
+	}
+	-re -wrap "<\\d+-byte float>" {
+	    # Assume 8 for anything less than or equal to 8.
+	    set size 8
+	}
+    }
+
+    return $size
+}
+
 clean_restart ${testfile}
 
 set bp_location [gdb_get_line_number "BREAK" ${testdir}/prog.adb]
@@ -42,29 +63,57 @@ gdb_test "print val_double := 16lf#bc0d83c94fb6d2ac#" " = -2.0e-19"
 gdb_test "print val_double" " = -2.0e-19" \
     "print val_double after assignment"
 
-set 16llf_supported 0
-gdb_test_multiple "ptype long_long_float" "" {
-    -re -wrap "<16-byte float>" {
-	set 16llf_supported 1
-	pass $gdb_test_name
-    }
-    -re -wrap "<\\d+-byte float>" {
-	pass $gdb_test_name
+# Fetch the size of a compiler-generated long double.
+set compiler_long_double_size [float_size "long_long_float" ]
+
+# Fetch the size of an internal long double type in GDB.
+set gdb_long_double_size [float_size "16llf#0#" ]
+
+# Different architectures use different long double formats.  For
+# example, IEEE quad versus i387 long doubles.  Account for that in the
+# tests below.
+
+# Set default values for 128-bit IEEE quad long doubles.
+set valid_long_double "16llf#4000921fb54442d18469898cc51701b8#"
+set printed_long_double "3.1415926535897932384626433832795028"
+set invalid_long_double ""
+set has_invalid_long_double 0
+
+if { [istarget x86_64-*-* ] || [istarget i?86-*-*] } {
+    # i387 long double have invalid values
+    set has_invalid_long_double 1
+    if { $compiler_long_double_size == 16 } {
+	# 5.0e+25 in i387 128-bit long double.
+	set valid_long_double "16llf#7ffff7ff4054a56fa5b99019a5c8#"
+	set invalid_long_double "16llf#a56fa5b99019a5c800007ffff7ff4054#"
+	set printed_long_double "5.0e\\+25"
+    } elseif { $compiler_long_double_size == 12 } {
+	# 5.0e+25 in i387 80-bit long double.
+	set valid_long_double "16llf#56554054a56fa5b99019a5c8#"
+	set invalid_long_double "16llf#9019a5c800007ffff7ff4054#"
+	set printed_long_double "5.0e\\+25"
     }
 }
 
-if { $16llf_supported } {
-    gdb_test "print 16llf#7FFFF7FF4054A56FA5B99019A5C8#" " = 5.0e\\+25"
+# Exercise GDB-side long doubles.
+if { $gdb_long_double_size > 8 } {
+    gdb_test "print ${valid_long_double}" " = ${printed_long_double}"
+    gdb_test "print \$foo:=${valid_long_double}" "= ${printed_long_double}"
+    gdb_test "print \$foo" "= ${printed_long_double}" \
+	"print internal long double variable after assignment"
 }
-gdb_test "print val_long_double" " = 5.0e\\+25"
-if { $16llf_supported } {
-    gdb_test "print val_long_double := 16llf#7FFFF7FF4054A56FA5B99019A5C8#" \
-	" = 5.0e\\+25"
+
+# Exercise compiler-side long doubles.
+if { $compiler_long_double_size > 8 } {
+    gdb_test "print val_long_double" " = 5.0e\\+25"
+    gdb_test "print val_long_double := ${valid_long_double}" \
+	" = ${printed_long_double}"
+    gdb_test "print val_long_double" " = ${printed_long_double}" \
+	"print val_long_double after assignment"
 }
-gdb_test "print val_long_double" " = 5.0e\\+25" \
-    "print val_long_double after assignment"
 
-if { $16llf_supported } {
-    gdb_test "print 16llf#a56fa5b99019a5c800007ffff7ff4054#" \
-	" = <invalid float value>"
+# If the target has invalid long double values, test it now.
+if { $has_invalid_long_double } {
+    gdb_test "print ${invalid_long_double}" \
+	" = <invalid float value>" "print invalid long double value"
 }