From 73fcf6418ddce47ead4ffde4fc9fea8e8bd1f4af Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Mon, 20 Nov 2017 23:03:17 +0000 Subject: [PATCH] Fix gdb.base/whatis-ptype-typedefs.exp on 32-bit archs The gdb.base/whatis-ptype-typedefs.exp testcase has several tests that fail on 32-bit architectures. E.g., on 'x86-64 -m32', I see: ... FAIL: gdb.base/whatis-ptype-typedefs.exp: lang=c: cast: whatis (float_typedef) v_uchar_array_t_struct_typedef (invalid) FAIL: gdb.base/whatis-ptype-typedefs.exp: lang=c: cast: ptype (float_typedef) v_uchar_array_t_struct_typedef (invalid) ... gdb.log: (gdb) whatis (float_typedef) v_uchar_array_t_struct_typedef type = float_typedef (gdb) FAIL: gdb.base/whatis-ptype-typedefs.exp: lang=c: cast: whatis (float_typedef) v_uchar_array_t_struct_typedef (invalid) As Simon explained [1], the issue boils down to the fact that on 64-bit, this is an invalid cast: (gdb) p (float_typedef) v_uchar_array_t_struct_typedef Invalid cast. while on 32 bits it is valid: (gdb) p (float_typedef) v_uchar_array_t_struct_typedef $1 = 1.16251721e-41 The expression basically tries to cast an array (which decays to a pointer) to a float. The cast works on 32 bits because a float and a pointer are of the same size, and value_cast works in that case: ~~~ More general than a C cast: accepts any two types of the same length, and if ARG2 is an lvalue it can be cast into anything at all. */ ~~~ On 64 bits, they are not the same size, so it ends throwing the "Invalid cast" error. The testcase is expecting the invalid cast behavior, thus the FAILs. A point of these tests was to cover as many code paths in value_cast as possible, as a sort of documentation of the current behavior: # The main idea here is testing all the different paths in the # value casting code in GDB (value_cast), making sure typedefs are # preserved. ... # We try all combinations, even those that don't parse, or are # invalid, to catch the case of a regression making them # inadvertently valid. For example, these convertions are # invalid: ... In that spirit, this commit makes the testcase adjust itself depending on size of floats and pointers, and also test floats of different sizes. Passes cleanly on x86-64 GNU/Linux both -m64/-m32. [1] - https://sourceware.org/ml/gdb-patches/2017-11/msg00382.html gdb/ChangeLog: 2017-11-20 Pedro Alves * gdb.base/whatis-ptype-typedefs.c (double_typedef) (long_double_typedef): New typedefs. Use DEF on double and long double. * gdb.base/whatis-ptype-typedefs.exp: Add double and long double cases. (run_tests): New 'float_ptr_same_size', 'double_ptr_same_size', and 'long_double_ptr_same_size' locals. Use them to decide whether cast from array/function to float is valid/invalid. --- gdb/testsuite/ChangeLog | 11 +++++++ gdb/testsuite/gdb.base/whatis-ptype-typedefs.c | 10 ++++++ gdb/testsuite/gdb.base/whatis-ptype-typedefs.exp | 39 ++++++++++++++++++++++-- 3 files changed, 57 insertions(+), 3 deletions(-) diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 12938e7..fa329b4 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,14 @@ +2017-11-20 Pedro Alves + + * gdb.base/whatis-ptype-typedefs.c (double_typedef) + (long_double_typedef): New typedefs. + Use DEF on double and long double. + * gdb.base/whatis-ptype-typedefs.exp: Add double and long double + cases. + (run_tests): New 'float_ptr_same_size', 'double_ptr_same_size', + and 'long_double_ptr_same_size' locals. Use them to decide + whether cast from array/function to float is valid/invalid. + 2017-11-17 Tom Tromey * gdb.rust/traits.rs: New file. diff --git a/gdb/testsuite/gdb.base/whatis-ptype-typedefs.c b/gdb/testsuite/gdb.base/whatis-ptype-typedefs.c index 5711a96..35c7279 100644 --- a/gdb/testsuite/gdb.base/whatis-ptype-typedefs.c +++ b/gdb/testsuite/gdb.base/whatis-ptype-typedefs.c @@ -56,6 +56,16 @@ DEF (int); typedef float float_typedef; DEF (float); +/* Double floats. */ + +typedef double double_typedef; +DEF (double); + +/* Long doubles. */ + +typedef long double long_double_typedef; +DEF (long_double); + /* Enums. */ typedef enum colors {red, green, blue} colors_typedef; diff --git a/gdb/testsuite/gdb.base/whatis-ptype-typedefs.exp b/gdb/testsuite/gdb.base/whatis-ptype-typedefs.exp index d333d81..ea0ef6c 100644 --- a/gdb/testsuite/gdb.base/whatis-ptype-typedefs.exp +++ b/gdb/testsuite/gdb.base/whatis-ptype-typedefs.exp @@ -92,6 +92,16 @@ set table { {"v_float_typedef" "float_typedef" "float"} {"v_float_typedef2" "float_typedef2" "float"} + {"double_typedef" "double" "double"} + {"double_typedef2" "double_typedef" "double"} + {"v_double_typedef" "double_typedef" "double"} + {"v_double_typedef2" "double_typedef2" "double"} + + {"long_double_typedef" "long double" "long double"} + {"long_double_typedef2" "long_double_typedef" "long double"} + {"v_long_double_typedef" "long_double_typedef" "long double"} + {"v_long_double_typedef2" "long_double_typedef2" "long double"} + {"colors_typedef" "(enum )?colors" "enum colors( : unsigned int)? {red, green, blue}"} {"colors_typedef2" "colors_typedef" "enum colors( : unsigned int)? {red, green, blue}"} {"v_colors_typedef" "colors_typedef" "enum colors( : unsigned int)? {red, green, blue}"} @@ -199,6 +209,22 @@ proc run_tests {lang} { } } + # If floats and pointers have the same size on this architecture, + # then casting from array/function to float works, because + # arrays/functions first decay to pointers, and then GDB's cast is + # more general than a C cast and accepts any two types of the same + # length. + set float_ptr_same_size \ + [get_integer_valueof "sizeof (float) == sizeof (void *)" -1] + + # Ditto double. + set double_ptr_same_size \ + [get_integer_valueof "sizeof (double) == sizeof (void *)" -1] + + # Ditto long double. + set long_double_ptr_same_size \ + [get_integer_valueof "sizeof (long double) == sizeof (void *)" -1] + # Test converting/casting all variables in the first column of the # table to all types (found in the first column of the table). # The aggregates are all defined to be the same size so that @@ -230,7 +256,7 @@ proc run_tests {lang} { # regression making them inadvertently valid. For # example, these convertions are invalid: # - # float <-> array + # float <-> array [iff sizeof pointer != sizeof float] # array -> function (not function pointer) # array -> member_ptr # @@ -247,8 +273,15 @@ proc run_tests {lang} { gdb_test "whatis ($to) $from" "syntax error.*" "whatis ($to) $from (syntax)" gdb_test "ptype ($to) $from" "syntax error.*" "ptype ($to) $from (syntax)" } elseif {([string match "*float*" $from] && [string match "*array*" $to]) - || ([string match "float*" $to] && [string match "*array*" $from]) - || ([string match "float*" $to] && [string match "*method" $from]) + || (!$float_ptr_same_size + && ([string match "float*" $to] && [string match "*array*" $from] + || [string match "float*" $to] && [string match "*method" $from])) + || (!$double_ptr_same_size + && ([string match "double*" $to] && [string match "*array*" $from] + || [string match "double*" $to] && [string match "*method" $from])) + || (!$long_double_ptr_same_size + && ([string match "long_double*" $to] && [string match "*array*" $from] + || [string match "long_double*" $to] && [string match "*method" $from])) || ([string match "*ftype" $to] && [string match "*array*" $from]) || ([string match "*ftype2" $to] && [string match "*array*" $from]) || ([string match "*ftype" $to] && [string match "*method" $from]) -- 2.7.4