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

["Aktemur, Tankut Baris" <tankut dot baris dot aktemur at intel dot com>]

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 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
> > +}
> >
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