RE: [review v3] testsuite, cp: increase the coverage of testing pass-by-ref arguments

Aktemur, Tankut Baris
2020-01-13T20:20:47Z

On Monday, January 13, 2020 8:38 PM, Luis Machado wrote:
>
> On 1/13/20 4:35 PM, Aktemur, Tankut Baris wrote:
> > On Monday, January 13, 2020 7:21 PM, Luis Machado wrote:
> >>
> >> Hi,
> >>
> >> I noticed these new tests fail (in large numbers) for GCC 5.4.x. Is it
> >> expected? If so, it may be worth making this test conditional on newer
> >> GCC versions.
> >>
> >
> > Yes, this is expected. Older GCC versions did not emit certain DWARF attributes
> > (DW_AT_deleted, DW_AT_defaulted). This prevents GDB from making the right
> > pass-by-reference decision. I'll submit a patch for this.
>
> Thanks for clarifying this.
>
> I can submit that patch if you like. I have a box running an older GCC,
> so i noticed that and thought i'd check.
>
> Luis

Yes, sure.

Thank you.

-Baris

>
> >
> > Thanks for the suggestion.
> >
> > -Baris
> >
> >> On 12/14/19 6:53 AM, Tankut Baris Aktemur (Code Review) wrote:
> >>> Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/142
> >>> ......................................................................
> >>>
> >>> testsuite, cp: increase the coverage of testing pass-by-ref arguments
> >>>
> >>> Extend testcases for GDB's infcall of call-by-value functions that
> >>> take aggregate values as parameters. In particular, existing test has
> >>> been substantially extended with class definitions whose definitions
> >>> of copy constructor, destructor, and move constructor functions are a
> >>> combination of
> >>>
> >>> (1) explicitly defined by the user,
> >>> (2) defaulted inside the class declaration,
> >>> (3) defaulted outside the class declaration,
> >>> (4) deleted
> >>> (5) not defined in the source.
> >>>
> >>> For each combination, a small and a large class is generated as well
> >>> as a derived class and a container class. Additionally, the following
> >>> manually-written cases are provided:
> >>>
> >>> - a dynamic class (i.e. class with a virtual method)
> >>> - classes that contain an array field
> >>> - a class whose copy ctor is inlined
> >>> - a class whose destructor is deleted
> >>> - classes with multiple copy and/or move ctors
> >>>
> >>> Test cases check whether GDB makes the right decision to pass an
> >>> object by value or implicitly by reference, whether really a copy of
> >>> the argument is passed, and whether the copy constructor and
> >>> destructor of the clone of the argument are invoked properly.
> >>>
> >>> The input program pass-by-ref.cc is generated in the test's output
> >>> directory. The input program pass-by-ref-2.cc is manually-written.
> >>>
> >>> Tests have been verified on the X86_64 architecture with
> >>> GCC 7.4.0, 8.2.0, and 9.2.1.
> >>>
> >>> gdb/testsuite/ChangeLog:
> >>> 2019-11-07 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
> >>>
> >>> * gdb.cp/pass-by-ref.cc: Delete. Generated in the output
> >>> directory instead.
> >>> * gdb.cp/pass-by-ref.exp: Extend with more cases.
> >>> * gdb.cp/pass-by-ref-2.cc: New file.
> >>> * gdb.cp/pass-by-ref-2.exp: New file.
> >>>
> >>> Change-Id: Ie8ab1f260c6ad5ee4eb34b2c1597ce24af04abb6
> >>> ---
> >>> A gdb/testsuite/gdb.cp/pass-by-ref-2.cc
> >>> A gdb/testsuite/gdb.cp/pass-by-ref-2.exp
> >>> D gdb/testsuite/gdb.cp/pass-by-ref.cc
> >>> M gdb/testsuite/gdb.cp/pass-by-ref.exp
> >>> 4 files changed, 791 insertions(+), 86 deletions(-)
> >>>
> >>>
> >>>
> >>> diff --git a/gdb/testsuite/gdb.cp/pass-by-ref-2.cc b/gdb/testsuite/gdb.cp/pass-by-ref-2.cc
> >>> new file mode 100644
> >>> index 0000000..1cd5a16
> >>> --- /dev/null
> >>> +++ b/gdb/testsuite/gdb.cp/pass-by-ref-2.cc
> >>> @@ -0,0 +1,295 @@
> >>> +/* This testcase is part of GDB, the GNU debugger.
> >>> +
> >>> + Copyright 2019 Free Software Foundation, Inc.
> >>> +
> >>> + This program is free software; you can redistribute it and/or modify
> >>> + it under the terms of the GNU General Public License as published by
> >>> + the Free Software Foundation; either version 3 of the License, or
> >>> + (at your option) any later version.
> >>> +
> >>> + This program is distributed in the hope that it will be useful,
> >>> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> >>> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> >>> + GNU General Public License for more details.
> >>> +
> >>> + You should have received a copy of the GNU General Public License
> >>> + along with this program. If not, see <http://www.gnu.org/licenses/>. */
> >>> +
> >>> +class ByVal {
> >>> +public:
> >>> + ByVal (void);
> >>> +
> >>> + int x;
> >>> +};
> >>> +
> >>> +ByVal::ByVal (void)
> >>> +{
> >>> + x = 2;
> >>> +}
> >>> +
> >>> +class ByRef {
> >>> +public:
> >>> + ByRef (void);
> >>> +
> >>> + ByRef (const ByRef &rhs);
> >>> +
> >>> + int x;
> >>> +};
> >>> +
> >>> +ByRef::ByRef (void)
> >>> +{
> >>> + x = 2;
> >>> +}
> >>> +
> >>> +ByRef::ByRef (const ByRef &rhs)
> >>> +{
> >>> + x = 3; /* ByRef-cctor */
> >>> +}
> >>> +
> >>> +class ArrayContainerByVal {
> >>> +public:
> >>> + ByVal items[2];
> >>> +};
> >>> +
> >>> +int
> >>> +cbvArrayContainerByVal (ArrayContainerByVal arg)
> >>> +{
> >>> + arg.items[0].x += 4; // intentionally modify
> >>> + return arg.items[0].x;
> >>> +}
> >>> +
> >>> +class ArrayContainerByRef {
> >>> +public:
> >>> + ByRef items[2];
> >>> +};
> >>> +
> >>> +int
> >>> +cbvArrayContainerByRef (ArrayContainerByRef arg)
> >>> +{
> >>> + arg.items[0].x += 4; // intentionally modify
> >>> + return arg.items[0].x;
> >>> +}
> >>> +
> >>> +class DynamicBase {
> >>> +public:
> >>> + DynamicBase (void);
> >>> +
> >>> + virtual int get (void);
> >>> +
> >>> + int x;
> >>> +};
> >>> +
> >>> +DynamicBase::DynamicBase (void)
> >>> +{
> >>> + x = 2;
> >>> +}
> >>> +
> >>> +int
> >>> +DynamicBase::get (void)
> >>> +{
> >>> + return 42;
> >>> +}
> >>> +
> >>> +class Dynamic : public DynamicBase {
> >>> +public:
> >>> + virtual int get (void);
> >>> +};
> >>> +
> >>> +int
> >>> +Dynamic::get (void)
> >>> +{
> >>> + return 9999;
> >>> +}
> >>> +
> >>> +int
> >>> +cbvDynamic (DynamicBase arg)
> >>> +{
> >>> + arg.x += 4; // intentionally modify
> >>> + return arg.x + arg.get ();
> >>> +}
> >>> +
> >>> +class Inlined {
> >>> +public:
> >>> + Inlined (void);
> >>> +
> >>> + __attribute__((always_inline))
> >>> + Inlined (const Inlined &rhs)
> >>> + {
> >>> + x = 3;
> >>> + }
> >>> +
> >>> + int x;
> >>> +};
> >>> +
> >>> +Inlined::Inlined (void)
> >>> +{
> >>> + x = 2;
> >>> +}
> >>> +
> >>> +int
> >>> +cbvInlined (Inlined arg)
> >>> +{
> >>> + arg.x += 4; // intentionally modify
> >>> + return arg.x;
> >>> +}
> >>> +
> >>> +class DtorDel {
> >>> +public:
> >>> + DtorDel (void);
> >>> +
> >>> + ~DtorDel (void) = delete;
> >>> +
> >>> + int x;
> >>> +};
> >>> +
> >>> +DtorDel::DtorDel (void)
> >>> +{
> >>> + x = 2;
> >>> +}
> >>> +
> >>> +int
> >>> +cbvDtorDel (DtorDel arg)
> >>> +{
> >>> + // Calling this method should be rejected
> >>> + return arg.x;
> >>> +}
> >>> +
> >>> +class FourCCtor {
> >>> +public:
> >>> + FourCCtor (void);
> >>> +
> >>> + FourCCtor (FourCCtor &rhs);
> >>> + FourCCtor (const FourCCtor &rhs);
> >>> + FourCCtor (volatile FourCCtor &rhs);
> >>> + FourCCtor (const volatile FourCCtor &rhs);
> >>> +
> >>> + int x;
> >>> +};
> >>> +
> >>> +FourCCtor::FourCCtor (void)
> >>> +{
> >>> + x = 2;
> >>> +}
> >>> +
> >>> +FourCCtor::FourCCtor (FourCCtor &rhs)
> >>> +{
> >>> + x = 3;
> >>> +}
> >>> +
> >>> +FourCCtor::FourCCtor (const FourCCtor &rhs)
> >>> +{
> >>> + x = 4;
> >>> +}
> >>> +
> >>> +FourCCtor::FourCCtor (volatile FourCCtor &rhs)
> >>> +{
> >>> + x = 5;
> >>> +}
> >>> +
> >>> +FourCCtor::FourCCtor (const volatile FourCCtor &rhs)
> >>> +{
> >>> + x = 6;
> >>> +}
> >>> +
> >>> +int
> >>> +cbvFourCCtor (FourCCtor arg)
> >>> +{
> >>> + arg.x += 10; // intentionally modify
> >>> + return arg.x;
> >>> +}
> >>> +
> >>> +class TwoMCtor {
> >>> +public:
> >>> + TwoMCtor (void);
> >>> +
> >>> + /* Even though one move ctor is defaulted, the other
> >>> + is explicit. */
> >>> + TwoMCtor (const TwoMCtor &&rhs);
> >>> + TwoMCtor (TwoMCtor &&rhs) = default;
> >>> +
> >>> + int x;
> >>> +};
> >>> +
> >>> +TwoMCtor::TwoMCtor (void)
> >>> +{
> >>> + x = 2;
> >>> +}
> >>> +
> >>> +TwoMCtor::TwoMCtor (const TwoMCtor &&rhs)
> >>> +{
> >>> + x = 3;
> >>> +}
> >>> +
> >>> +int
> >>> +cbvTwoMCtor (TwoMCtor arg)
> >>> +{
> >>> + arg.x += 10; // intentionally modify
> >>> + return arg.x;
> >>> +}
> >>> +
> >>> +class TwoMCtorAndCCtor {
> >>> +public:
> >>> + TwoMCtorAndCCtor (void);
> >>> +
> >>> + TwoMCtorAndCCtor (const TwoMCtorAndCCtor &rhs) = default;
> >>> +
> >>> + /* Even though one move ctor is defaulted, the other
> >>> + is explicit. This makes the type pass-by-ref. */
> >>> + TwoMCtorAndCCtor (const TwoMCtorAndCCtor &&rhs);
> >>> + TwoMCtorAndCCtor (TwoMCtorAndCCtor &&rhs) = default;
> >>> +
> >>> + int x;
> >>> +};
> >>> +
> >>> +TwoMCtorAndCCtor::TwoMCtorAndCCtor (void)
> >>> +{
> >>> + x = 2;
> >>> +}
> >>> +
> >>> +TwoMCtorAndCCtor::TwoMCtorAndCCtor (const TwoMCtorAndCCtor &&rhs)
> >>> +{
> >>> + x = 4;
> >>> +}
> >>> +
> >>> +int
> >>> +cbvTwoMCtorAndCCtor (TwoMCtorAndCCtor arg)
> >>> +{
> >>> + arg.x += 10; // intentionally modify
> >>> + return arg.x;
> >>> +}
> >>> +
> >>> +ArrayContainerByVal arrayContainerByVal;
> >>> +ArrayContainerByRef arrayContainerByRef;
> >>> +Dynamic dynamic;
> >>> +Inlined inlined;
> >>> +// Cannot stack-allocate DtorDel
> >>> +DtorDel *dtorDel;
> >>> +FourCCtor fourCctor_c0v0;
> >>> +const FourCCtor fourCctor_c1v0;
> >>> +volatile FourCCtor fourCctor_c0v1;
> >>> +const volatile FourCCtor fourCctor_c1v1;
> >>> +TwoMCtor twoMctor;
> >>> +TwoMCtorAndCCtor twoMctorAndCctor;
> >>> +
> >>> +int
> >>> +main (void)
> >>> +{
> >>> + int v;
> >>> + dtorDel = new DtorDel;
> >>> + /* Explicitly call the cbv function to make sure the compiler
> >>> + will not omit any code in the binary. */
> >>> + v = cbvArrayContainerByVal (arrayContainerByVal);
> >>> + v = cbvArrayContainerByRef (arrayContainerByRef);
> >>> + v = cbvDynamic (dynamic);
> >>> + v = cbvInlined (inlined);
> >>> + v = cbvFourCCtor (fourCctor_c0v0);
> >>> + v = cbvFourCCtor (fourCctor_c1v0);
> >>> + v = cbvFourCCtor (fourCctor_c0v1);
> >>> + v = cbvFourCCtor (fourCctor_c1v1);
> >>> + /* v = cbvTwoMCtor (twoMctor); */ // This is illegal, cctor is deleted
> >>> + v = cbvTwoMCtorAndCCtor (twoMctorAndCctor);
> >>> +
> >>> + /* stop here */
> >>> +
> >>> + return 0;
> >>> +}
> >>> diff --git a/gdb/testsuite/gdb.cp/pass-by-ref-2.exp b/gdb/testsuite/gdb.cp/pass-by-ref-2.exp
> >>> new file mode 100644
> >>> index 0000000..7cce886
> >>> --- /dev/null
> >>> +++ b/gdb/testsuite/gdb.cp/pass-by-ref-2.exp
> >>> @@ -0,0 +1,114 @@
> >>> +# Copyright 2019 Free Software Foundation, Inc.
> >>> +
> >>> +# This program is free software; you can redistribute it and/or modify
> >>> +# it under the terms of the GNU General Public License as published by
> >>> +# the Free Software Foundation; either version 3 of the License, or
> >>> +# (at your option) any later version.
> >>> +#
> >>> +# This program is distributed in the hope that it will be useful,
> >>> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> >>> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> >>> +# GNU General Public License for more details.
> >>> +#
> >>> +# You should have received a copy of the GNU General Public License
> >>> +# along with this program. If not, see <http://www.gnu.org/licenses/>.
> >>> +
> >>> +# Check that GDB can call C++ functions whose parameters have
> >>> +# object type, and are either passed by value or implicitly by reference.
> >>> +#
> >>> +# This is a companion test to pass-by-ref.exp. In this test, the input
> >>> +# is manually-written. In pass-by-ref.exp, the test input is generated.
> >>> +#
> >>> +# We include tests for classes that
> >>> +# - contain arrays as fields,
> >>> +# - are dynamic (i.e. have virtual methods)
> >>> +# - have inlined copy ctor
> >>> +# - have deleted destructor
> >>> +
> >>> +if {[skip_cplus_tests]} {
> >>> + untested "c++ test skipped"
> >>> + continue
> >>> +}
> >>> +
> >>> +standard_testfile .cc
> >>> +
> >>> +set options {debug c++ additional_flags=-std=c++11}
> >>> +if {[prepare_for_testing "failed to prepare" $testfile $srcfile $options]} {
> >>> + return -1
> >>> +}
> >>> +
> >>> +if {![runto_main]} {
> >>> + untested "failed to run to main"
> >>> + return -1
> >>> +}
> >>> +
> >>> +set bp_location [gdb_get_line_number "stop here"]
> >>> +gdb_breakpoint $bp_location
> >>> +gdb_continue_to_breakpoint "end of main" ".*return .*;"
> >>> +
> >>> +gdb_test "print cbvArrayContainerByVal (arrayContainerByVal)" "6" \
> >>> + "call cbvArrayContainerByVal"
> >>> +gdb_test "print arrayContainerByVal.items\[0\].x" "2" \
> >>> + "cbv argument 'arrayContainerByVal' should not change"
> >>> +
> >>> +gdb_test "print cbvArrayContainerByRef (arrayContainerByRef)" "7" \
> >>> + "call cbvArrayContainerByRef"
> >>> +gdb_test "print arrayContainerByRef.items\[0\].x" "2" \
> >>> + "cbv argument 'arrayContainerByRef' should not change"
> >>> +
> >>> +gdb_test "print cbvDynamic (dynamic)" "48" \
> >>> + "call cbvDynamic"
> >>> +gdb_test "print dynamic.x" "2" \
> >>> + "cbv argument 'dynamic' should not change"
> >>> +
> >>> +set sig "\"Inlined\:\:Inlined\\(.*Inlined const\&\\)\""
> >>> +gdb_test "print cbvInlined (inlined)" \
> >>> + "expression cannot be evaluated .* \\(maybe inlined\\?\\)"
> >>> +
> >>> +gdb_test "print cbvDtorDel (*dtorDel)" \
> >>> + ".* cannot be evaluated .* 'DtorDel' is not destructible" \
> >>> + "type not destructible"
> >>> +
> >>> +# Test that GDB calls the correct copy ctor
> >>> +gdb_test "print cbvFourCCtor (fourCctor_c0v0)" "13" \
> >>> + "call cbvFourCCtor (c0v0)"
> >>> +gdb_test "print fourCctor_c0v0.x" "2" \
> >>> + "cbv argument 'twoCctor_c0v0' should not change"
> >>> +
> >>> +gdb_test "print cbvFourCCtor (fourCctor_c1v0)" "14" \
> >>> + "call cbvFourCCtor (c1v0)"
> >>> +gdb_test "print fourCctor_c1v0.x" "2" \
> >>> + "cbv argument 'twoCctor_c1v0' should not change"
> >>> +
> >>> +gdb_test "print cbvFourCCtor (fourCctor_c0v1)" "15" \
> >>> + "call cbvFourCCtor (c0v1)"
> >>> +gdb_test "print fourCctor_c0v1.x" "2" \
> >>> + "cbv argument 'twoCctor_c0v1' should not change"
> >>> +
> >>> +gdb_test "print cbvFourCCtor (fourCctor_c1v1)" "16" \
> >>> + "call cbvFourCCtor (c1v1)"
> >>> +gdb_test "print fourCctor_c1v1.x" "2" \
> >>> + "cbv argument 'twoCctor_c1v1' should not change"
> >>> +
> >>> +gdb_test "print cbvTwoMCtor (twoMctor)" \
> >>> + ".* cannot be evaluated .* 'TwoMCtor' is not copy constructible" \
> >>> + "copy ctor is implicitly deleted"
> >>> +
> >>> +gdb_test "print cbvTwoMCtorAndCCtor (twoMctorAndCctor)" "12" \
> >>> + "call cbvTwoMCtorAndCCtor"
> >>> +gdb_test "print twoMctorAndCctor.x" "2" \
> >>> + "cbv argument 'twoMctorAndCtor' should not change"
> >>> +
> >>> +# Test that we get a breakpoint from the cctor during infcall and
> >>> +# we can examine arguments. This is a test that the dummy frame
> >>> +# of the copy constructor is set up correctly by the infcall mechanism.
> >>> +set bp_location [gdb_get_line_number "ByRef-cctor"]
> >>> +gdb_breakpoint $bp_location
> >>> +gdb_test "print cbvArrayContainerByRef (arrayContainerByRef)" \
> >>> + ".*The program being debugged stopped.*" \
> >>> + "call cbvArrayContainerByRef with BP"
> >>> +gdb_test "backtrace" [multi_line \
> >>> + "#0 ByRef\:\:ByRef .* at .*$srcfile:$bp_location" \
> >>> + "#1 .* ArrayContainerByRef::ArrayContainerByRef .*" \
> >>> + "#2 <function called from gdb>" \
> >>> + "#3 main.*"]
> >>> diff --git a/gdb/testsuite/gdb.cp/pass-by-ref.cc b/gdb/testsuite/gdb.cp/pass-by-ref.cc
> >>> deleted file mode 100644
> >>> index bbe450a..0000000
> >>> --- a/gdb/testsuite/gdb.cp/pass-by-ref.cc
> >>> +++ /dev/null
> >>> @@ -1,79 +0,0 @@
> >>> -/* This testcase is part of GDB, the GNU debugger.
> >>> -
> >>> - Copyright 2007-2019 Free Software Foundation, Inc.
> >>> -
> >>> - This program is free software; you can redistribute it and/or modify
> >>> - it under the terms of the GNU General Public License as published by
> >>> - the Free Software Foundation; either version 3 of the License, or
> >>> - (at your option) any later version.
> >>> -
> >>> - This program is distributed in the hope that it will be useful,
> >>> - but WITHOUT ANY WARRANTY; without even the implied warranty of
> >>> - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> >>> - GNU General Public License for more details.
> >>> -
> >>> - You should have received a copy of the GNU General Public License
> >>> - along with this program. If not, see <http://www.gnu.org/licenses/>. */
> >>> -
> >>> -class Obj {
> >>> -public:
> >>> - Obj ();
> >>> - Obj (const Obj &);
> >>> - ~Obj ();
> >>> - int var[2];
> >>> -};
> >>> -
> >>> -int foo (Obj arg)
> >>> -{
> >>> - return arg.var[0] + arg.var[1];
> >>> -}
> >>> -
> >>> -Obj::Obj ()
> >>> -{
> >>> - var[0] = 1;
> >>> - var[1] = 2;
> >>> -}
> >>> -
> >>> -Obj::Obj (const Obj &obj)
> >>> -{
> >>> - var[0] = obj.var[0];
> >>> - var[1] = obj.var[1];
> >>> -}
> >>> -
> >>> -Obj::~Obj ()
> >>> -{
> >>> -
> >>> -}
> >>> -
> >>> -struct Derived : public Obj
> >>> -{
> >>> - int other;
> >>> -};
> >>> -
> >>> -int blap (Derived arg)
> >>> -{
> >>> - return foo (arg);
> >>> -}
> >>> -
> >>> -struct Container
> >>> -{
> >>> - Obj obj;
> >>> -};
> >>> -
> >>> -int blip (Container arg)
> >>> -{
> >>> - return foo (arg.obj);
> >>> -}
> >>> -
> >>> -Obj global_obj;
> >>> -Derived global_derived;
> >>> -Container global_container;
> >>> -
> >>> -int
> >>> -main ()
> >>> -{
> >>> - int bar = foo (global_obj);
> >>> - blap (global_derived);
> >>> - blip (global_container);
> >>> - return bar;
> >>> -}
> >>> diff --git a/gdb/testsuite/gdb.cp/pass-by-ref.exp b/gdb/testsuite/gdb.cp/pass-by-ref.exp
> >>> index 94dd345..f44be77 100644
> >>> --- a/gdb/testsuite/gdb.cp/pass-by-ref.exp
> >>> +++ b/gdb/testsuite/gdb.cp/pass-by-ref.exp
> >>> @@ -14,20 +14,395 @@
> >>> # along with this program. If not, see <http://www.gnu.org/licenses/>.
> >>>
> >>> # Check that GDB can call C++ functions whose parameters have
> >>> -# object type, but are passed by reference.
> >>> +# object type, and are either passed by value or implicitly by reference.
> >>> +#
> >>> +# Suppose F is a function that has a call-by-value parameter whose
> >>> +# type is class C. When calling F with an argument A, a copy of A should
> >>> +# be created and passed to F. If C is a trivially-copyable type, A can
> >>> +# be copied by a straightforward memory copy. However, roughly speaking,
> >>> +# if C has a user-defined copy constructor and/or a user-defined
> >>> +# destructor, the copy ctor should be used to initialize the copy of A
> >>> +# before calling F, and a reference to that copy is passed to F. After
> >>> +# the function returns, the destructor should be called to destruct the
> >>> +# copy. In this case, C is said to be a 'pass-by-reference' type.
> >>> +# Determining whether C is pass-by-ref depends on
> >>> +# how the copy ctor, destructor, and the move ctor of C are defined.
> >>> +# First of all, C is not copy constructible if its copy constructor is
> >>> +# explicitly or implicitly deleted. In this case, it would be illegal
> >>> +# to pass values of type C to a function. C is pass-by-value, if all of
> >>> +# its copy ctor, dtor, and move ctor are trivially defined.
> >>> +# Otherwise, it is pass-by-ref.
> >>> +#
> >>> +# To cover the many possible combinations, this test generates classes
> >>> +# that contain three special functions:
> >>> +# (1) a copy constructor,
> >>> +# (2) a destructor, and
> >>> +# (3) a move constructor.
> >>> +# A special function is in one of the following states:
> >>> +# * explicit: The function is explicitly defined by the user.
> >>> +# * defaultedIn: The function is defaulted inside the class decl,
> >>> +# using the 'default' keyword.
> >>> +# * defaultedOut: The function is declared inside the class decl,
> >>> +# and defaulted outside using the 'default' keyword.
> >>> +# * deleted: The function is explicitly deleted by the user,
> >>> +# using the 'delete' keyword.
> >>> +# * absent: The function is not declared by the user (i.e. it does not
> >>> +# exist in the source. The compiler generates (or deletes) the
> >>> +# definition in this case.
> >>> +#
> >>> +# The C++ ABI decides if a class is pass-by-value or pass-by-ref
> >>> +# (i.e. trivially copyable or not) first at the language level, based
> >>> +# on the state of the special functions. Then, at the target level, a
> >>> +# class may be determined to be pass-by-ref because of its size
> >>> +# (e.g. if it is too large to fit on registers). For this reason, this
> >>> +# test generates both a small and a large version for the same
> >>> +# combination of special function states.
> >>> +#
> >>> +# A class is not trivially-copyable if a base class or a field is not
> >>> +# trivially-copyable, even though the class definition itself seems
> >>> +# trivial. To test these cases, we also generate derived classes and
> >>> +# container classes.
> >>> +#
> >>> +# The generated code is placed in the test output directory.
> >>> +#
> >>> +# The companion test file pass-by-ref-2.exp also contains
> >>> +# manually-written cases.
> >>>
> >>> -if { [skip_cplus_tests] } { continue }
> >>> +if {[skip_cplus_tests]} {
> >>> + untested "c++ test skipped"
> >>> + continue
> >>> +}
> >>>
> >>> +# The program source is generated in the output directory.
> >>> +# We use standard_testfile here to set convenience variables.
> >>> standard_testfile .cc
> >>>
> >>> -if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug c++}]} {
> >>> +# Some constant values used when generating the source
> >>> +
> >>> +set SMALL 2
> >>> +set LARGE 150
> >>> +set ORIGINAL 2
> >>> +set CUSTOM 3
> >>> +set ADDED 4
> >>> +set TRACE 5
> >>> +
> >>> +
> >>> +# Return 1 if the class whose special function states are STATES
> >>> +# is copyable. Otherwise return 0.
> >>> +
> >>> +proc is_copy_constructible { states } {
> >>> + set cctor [lindex $states 0]
> >>> + set dtor [lindex $states 1]
> >>> + set mctor [lindex $states 2]
> >>> +
> >>> + if {$cctor == "deleted" || ($cctor == "absent" && $mctor != "absent")} {
> >>> + return 0
> >>> + }
> >>> + return 1
> >>> +}
> >>> +
> >>> +# Generate a declaration and an out-of-class definition for a function
> >>> +# with the provided signature. The STATE should be one of the following:
> >>> +# - explicit, defaultedIn, defaultedOut, deleted, absent
> >>> +
> >>> +proc generate_member_function { classname signature length state } {
> >>> + set declaration ""
> >>> + set definition ""
> >>> +
> >>> + global CUSTOM
> >>> + global TRACE
> >>> +
> >>> + switch $state {
> >>> + explicit {
> >>> + set declaration "$signature;\n"
> >>> + set definition "$classname\:\:$signature
> >>> + {
> >>> + data\[0\] = $CUSTOM;
> >>> + data\[[expr $length - 1]\] = $CUSTOM;
> >>> + tracer = $TRACE;
> >>> + }\n"
> >>> + }
> >>> + defaultedIn {
> >>> + set declaration "$signature = default;\n"
> >>> + }
> >>> + defaultedOut {
> >>> + set declaration "$signature;\n"
> >>> + set definition "$classname\:\:$signature = default;\n"
> >>> + }
> >>> + deleted {
> >>> + set declaration "$signature = delete;\n"
> >>> + }
> >>> + default {
> >>> + # function is not user-defined in this case
> >>> + }
> >>> + }
> >>> +
> >>> + return [list $declaration $definition]
> >>> +}
> >>> +
> >>> +# Generate a C++ class with the given CLASSNAME and LENGTH-many
> >>> +# integer elements. The STATES is an array of 3 items
> >>> +# containing the desired state of the special functions
> >>> +# in this order:
> >>> +# copy constructor, destructor, move constructor
> >>> +
> >>> +proc generate_class { classname length states } {
> >>> + set declarations ""
> >>> + set definitions ""
> >>> + set classname "${classname}_[join $states _]"
> >>> +
> >>> + for {set i 0} {$i < [llength $states]} {incr i} {
> >>> + set sig ""
> >>> + switch $i {
> >>> + 0 {set sig "$classname (const $classname \&rhs)"}
> >>> + 1 {set sig "\~$classname (void)"}
> >>> + 2 {set sig "$classname ($classname \&\&rhs)"}
> >>> + }
> >>> +
> >>> + set state [lindex $states $i]
> >>> + set code [generate_member_function $classname $sig $length $state]
> >>> + append declarations [lindex $code 0]
> >>> + append definitions [lindex $code 1]
> >>> + }
> >>> +
> >>> + global ORIGINAL
> >>> +
> >>> + return "
> >>> + /*** C++ class $classname ***/
> >>> + class ${classname} {
> >>> + public:
> >>> + $classname (void);
> >>> + $declarations
> >>> +
> >>> + int data\[$length\];
> >>> + };
> >>> +
> >>> + $classname\:\:$classname (void)
> >>> + {
> >>> + data\[0\] = $ORIGINAL;
> >>> + data\[[expr $length - 1]\] = $ORIGINAL;
> >>> + }
> >>> +
> >>> + $definitions
> >>> +
> >>> + $classname ${classname}_var; /* global var */
> >>> +
> >>> + template int cbv<$classname> ($classname arg);"
> >>> +}
> >>> +
> >>> +# Generate a small C++ class
> >>> +
> >>> +proc generate_small_class { states } {
> >>> + global SMALL
> >>> + return [generate_class Small $SMALL $states];
> >>> +}
> >>> +
> >>> +# Generate a large C++ class
> >>> +
> >>> +proc generate_large_class { states } {
> >>> + global LARGE
> >>> + return [generate_class Large $LARGE $states];
> >>> +}
> >>> +
> >>> +# Generate a class that derives from a small class
> >>> +
> >>> +proc generate_derived_class { states } {
> >>> + set base "Small_[join $states _]"
> >>> + set classname "Derived_[join $states _]"
> >>> +
> >>> + return "
> >>> + /*** Class derived from $base ***/
> >>> + class $classname : public $base {
> >>> + public:
> >>> + };
> >>> +
> >>> + $classname ${classname}_var; /* global var */
> >>> +
> >>> + template int cbv<$classname> ($classname arg);"
> >>> +}
> >>> +
> >>> +# Generate a class that contains a small class item
> >>> +
> >>> +proc generate_container_class { states } {
> >>> + set contained "Small_[join $states _]"
> >>> + set classname "Container_[join $states _]"
> >>> +
> >>> + return "
> >>> + /*** Class that contains $contained ***/
> >>> + class $classname {
> >>> + public:
> >>> + $contained item;
> >>> + };
> >>> +
> >>> + $classname ${classname}_var; /* global var */
> >>> +
> >>> + template int cbv_container<$classname> ($classname arg);"
> >>> +}
> >>> +
> >>> +# Generate useful statements that use a class in the debugee program
> >>> +
> >>> +proc generate_stmts { classprefix states {cbvfun "cbv"}} {
> >>> + set classname "${classprefix}_[join $states _]"
> >>> +
> >>> + # Having an explicit call to the cbv function in the debugee program
> >>> + # ensures that the compiler will emit necessary function in the binary.
> >>> + if {[is_copy_constructible $states]} {
> >>> + set cbvcall "$cbvfun<$classname> (${classname}_var);\n"
> >>> + } else {
> >>> + set cbvcall ""
> >>> + }
> >>> +
> >>> + return "$cbvcall"
> >>> +}
> >>> +
> >>> +# Generate the complete debugee program
> >>> +
> >>> +proc generate_program { classes stmts } {
> >>> + global ADDED
> >>> +
> >>> + return "
> >>> + /*** THIS FILE IS GENERATED BY THE TEST. ***/
> >>> +
> >>> + static int tracer = 0;
> >>> +
> >>> + /* The call-by-value function. */
> >>> + template <class T>
> >>> + int
> >>> + cbv (T arg)
> >>> + {
> >>> + arg.data\[0\] += $ADDED; // intentionally modify the arg
> >>> + return arg.data\[0\];
> >>> + }
> >>> +
> >>> + template <class T>
> >>> + int
> >>> + cbv_container (T arg)
> >>> + {
> >>> + arg.item.data\[0\] += $ADDED; // intentionally modify
> >>> + return arg.item.data\[0\];
> >>> + }
> >>> +
> >>> + $classes
> >>> +
> >>> + int
> >>> + main (void)
> >>> + {
> >>> + $stmts
> >>> +
> >>> + /* stop here */
> >>> +
> >>> + return 0;
> >>> + }"
> >>> +}
> >>> +
> >>> +# Compute all the combinations of special function states.
> >>> +# We do not contain the 'deleted' state for the destructor,
> >>> +# because it is illegal to have stack-allocated objects
> >>> +# whose destructor have been deleted. This case is covered
> >>> +# in pass-by-ref-2 via heap-allocated objects.
> >>> +
> >>> +set options_nodelete [list absent explicit defaultedIn defaultedOut]
> >>> +set options [concat $options_nodelete {deleted}]
> >>> +set all_combinations {}
> >>> +
> >>> +foreach cctor $options {
> >>> + foreach dtor $options_nodelete {
> >>> + foreach mctor $options {
> >>> + lappend all_combinations [list $cctor $dtor $mctor]
> >>> + }
> >>> + }
> >>> +}
> >>> +
> >>> +# Generate the classes.
> >>> +
> >>> +set classes ""
> >>> +set stmts ""
> >>> +
> >>> +foreach state $all_combinations {
> >>> + append classes [generate_small_class $state]
> >>> + append stmts [generate_stmts "Small" $state]
> >>> +
> >>> + append classes [generate_large_class $state]
> >>> + append stmts [generate_stmts "Large" $state]
> >>> +
> >>> + append classes [generate_derived_class $state]
> >>> + append stmts [generate_stmts "Derived" $state]
> >>> +
> >>> + append classes [generate_container_class $state]
> >>> + append stmts [generate_stmts "Container" $state "cbv_container"]
> >>> +}
> >>> +
> >>> +# Generate the program code and compile
> >>> +set program [generate_program $classes $stmts]
> >>> +set srcfile [standard_output_file ${srcfile}]
> >>> +gdb_produce_source $srcfile $program
> >>> +
> >>> +set options {debug c++ additional_flags=-std=c++11}
> >>> +if {[prepare_for_testing "failed to prepare" $testfile $srcfile $options]} {
> >>> return -1
> >>> }
> >>>
> >>> -if ![runto_main] then {
> >>> +if {![runto_main]} {
> >>> + untested "failed to run to main"
> >>> return -1
> >>> }
> >>>
> >>> -gdb_test "print foo (global_obj)" " = 3" "call function in obj"
> >>> -gdb_test "print blap (global_derived)" " = 3" "call function in derived"
> >>> -gdb_test "print blip (global_container)" " = 3" "call function in container"
> >>> +set bp_location [gdb_get_line_number "stop here"]
> >>> +gdb_breakpoint $bp_location
> >>> +gdb_continue_to_breakpoint "end of main" ".*return .*;"
> >>> +
> >>> +# Do the checks for a given class whose name is prefixed with PREFIX,
> >>> +# and whose special functions have the states given in STATES.
> >>> +# The name of the call-by-value function and the expression to access
> >>> +# the data field can be specified explicitly if the default values
> >>> +# do not work.
> >>> +
> >>> +proc test_for_class { prefix states cbvfun data_field length} {
> >>> + set name "${prefix}_[join $states _]"
> >>> +
> >>> + set cctor [lindex $states 0]
> >>> + set dtor [lindex $states 1]
> >>> + set mctor [lindex $states 2]
> >>> +
> >>> + global ORIGINAL
> >>> + global CUSTOM
> >>> + global ADDED
> >>> + global TRACE
> >>> +
> >>> + with_test_prefix $name {
> >>> + if {[is_copy_constructible $states]} {
> >>> + set expected [expr {$ORIGINAL + $ADDED}]
> >>> + if {$cctor == "explicit"} {
> >>> + set expected [expr {$CUSTOM + $ADDED}]
> >>> + }
> >>> + if {$dtor == "explicit"} {
> >>> + gdb_test "print tracer = 0" " = 0" "reset the tracer"
> >>> + }
> >>> + gdb_test "print ${cbvfun}<$name> (${name}_var)" " = $expected" \
> >>> + "call '$cbvfun'"
> >>> + gdb_test "print ${name}_var.${data_field}\[0\]" " = $ORIGINAL" \
> >>> + "cbv argument should not change (item 0)"
> >>> + if {$length > 1} {
> >>> + set last_index [expr $length - 1]
> >>> + gdb_test "print ${name}_var.${data_field}\[$last_index\]" \
> >>> + " = $ORIGINAL" \
> >>> + "cbv argument should not change (item $last_index)"
> >>> + }
> >>> + if {$dtor == "explicit"} {
> >>> + gdb_test "print tracer" " = $TRACE" \
> >>> + "destructor should be called"
> >>> + }
> >>> + } else {
> >>> + gdb_test "print ${cbvfun}<$name> (${name}_var)" \
> >>> + ".* cannot be evaluated .* '${name}' is not copy constructible" \
> >>> + "calling '$cbvfun' should be refused"
> >>> + }
> >>> + }
> >>> +}
> >>> +
> >>> +foreach state $all_combinations {
> >>> + test_for_class "Small" $state "cbv" "data" $SMALL
> >>> + test_for_class "Large" $state "cbv" "data" $LARGE
> >>> + test_for_class "Derived" $state "cbv" "data" 1
> >>> + test_for_class "Container" $state "cbv_container" "item.data" 1
> >>> +}
> >>>
> > Intel Deutschland GmbH
> > Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany
> > Tel: +49 89 99 8853-0, www.intel.de
> > Managing Directors: Christin Eisenschmid, Gary Kershaw
> > Chairperson of the Supervisory Board: Nicole Lau
> > Registered Office: Munich
> > Commercial Register: Amtsgericht Muenchen HRB 186928
> >
Intel Deutschland GmbH
Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de
Managing Directors: Christin Eisenschmid, Gary Kershaw
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928