+++ /dev/null
-*** Changes in GCC 3.4:
-
-* Changes in GCC 3.4 are described in 'gcc-3.4/changes.html'
-
-*** Changes in GCC 3.3:
-
-* The "new X = 3" extension has been removed; you must now use "new X(3)".
-
-* G++ no longer allows in-class initializations of static data members
- that do not have arithmetic or enumeration type. For example:
-
- struct S {
- static const char* const p = "abc";
- };
-
- is no longer accepted.
-
- Use the standards-conformant form:
-
- struct S {
- static const char* const p;
- };
-
- const char* const S::p = "abc";
-
- instead.
-
- (ISO C++ is even stricter; it does not allow in-class
- initializations of floating-point types.)
-
-*** Changes in GCC 3.1:
-
-* -fhonor-std and -fno-honor-std have been removed. -fno-honor-std was
- a workaround to allow std compliant code to work with the non-std
- compliant libstdc++-v2. libstdc++-v3 is std compliant.
-
-* The C++ ABI has been fixed so that `void (A::*)() const' is mangled as
- "M1AKFvvE", rather than "MK1AFvvE" as before. This change only affects
- pointer to cv-qualified member function types.
-
-* The C++ ABI has been changed to correctly handle this code:
-
- struct A {
- void operator delete[] (void *, size_t);
- };
-
- struct B : public A {
- };
-
- new B[10];
-
- The amount of storage allocated for the array will be greater than
- it was in 3.0, in order to store the number of elements in the
- array, so that the correct size can be passed to `operator delete[]'
- when the array is deleted. Previously, the value passed to
- `operator delete[]' was unpredictable.
-
- This change will only affect code that declares a two-argument
- `operator delete[]' with a second parameter of type `size_t'
- in a base class, and does not override that definition in a
- derived class.
-
-* The C++ ABI has been changed so that:
-
- struct A {
- void operator delete[] (void *, size_t);
- void operator delete[] (void *);
- };
-
- does not cause unnecessary storage to be allocated when an array of
- `A' objects is allocated.
-
- This change will only affect code that declares both of these
- forms of `operator delete[]', and declared the two-argument form
- before the one-argument form.
-
-* The C++ ABI has been changed so that when a parameter is passed by value,
- any cleanup for that parameter is performed in the caller, as specified
- by the ia64 C++ ABI, rather than the called function as before. As a
- result, classes with a non-trivial destructor but a trivial copy
- constructor will be passed and returned by invisible reference, rather
- than by bitwise copy as before.
-
-* G++ now supports the "named return value optimization": for code like
-
- A f () {
- A a;
- ...
- return a;
- }
-
- G++ will allocate 'a' in the return value slot, so that the return
- becomes a no-op. For this to work, all return statements in the function
- must return the same variable.
-
-*** Changes in GCC 3.0:
-
-* Support for guiding declarations has been removed.
-
-* G++ now supports importing member functions from base classes with a
- using-declaration.
-
-* G++ now enforces access control for nested types.
-
-* In some obscure cases, functions with the same type could have the
- same mangled name. This bug caused compiler crashes, link-time clashes,
- and debugger crashes. Fixing this bug required breaking ABI
- compatibility for the functions involved. The functions in questions
- are those whose types involve non-type template arguments whose
- mangled representations require more than one digit.
-
-* Support for assignment to `this' has been removed. This idiom
- was used in the very early days of C++, before users were allowed
- to overload `operator new'; it is no longer allowed by the C++
- standard.
-
-* Support for signatures, a G++ extension, have been removed.
-
-* Certain invalid conversions that were previously accepted will now
- be rejected. For example, assigning function pointers of one type
- to function pointers of another type now requires a cast, whereas
- previously g++ would sometimes accept the code even without the
- cast.
-
-* G++ previously allowed `sizeof (X::Y)' where Y was a non-static
- member of X, even if the `sizeof' expression occurred outside
- of a non-static member function of X (or one of its derived classes,
- or a member-initializer for X or one of its derived classes.) This
- extension has been removed.
-
-* G++ no longer allows you to overload the conditional operator (i.e.,
- the `?:' operator.)
-
-* The "named return value" extension:
-
- int f () return r { r = 3; }
-
- has been deprecated, and will be removed in a future version of G++.
-
-*** Changes in GCC 2.95:
-
-* Messages about non-conformant code that we can still handle ("pedwarns")
- are now errors by default, rather than warnings. This can be reverted
- with -fpermissive, and is overridden by -pedantic or -pedantic-errors.
-
-* String constants are now of type `const char[n]', rather than `char[n]'.
- This can be reverted with -fno-const-strings.
-
-* References to functions are now supported.
-
-* Lookup of class members during class definition now works in all cases.
-
-* In overload resolution, type conversion operators are now properly
- treated as always coming from the most derived class.
-
-* C9x-style restricted pointers are supported, using the `__restrict'
- keyword.
-
-* You can now use -fno-implicit-inline-templates to suppress writing out
- implicit instantiations of inline templates. Normally we do write them
- out, even with -fno-implicit-templates, so that optimization doesn't
- affect which instantiations are needed.
-
-* -fstrict-prototype now also suppresses implicit declarations.
-
-* Many obsolete options have been removed: -fall-virtual, -fmemoize-lookups,
- -fsave-memoized, +e?, -fenum-int-equivalence, -fno-nonnull-objects.
-
-* Unused virtual functions can be discarded on some targets by specifying
- -ffunction-sections -fvtable-gc to the compiler and --gc-sections to the
- linker. Unfortunately, this only works on GNU/Linux if you're linking
- statically.
-
-* Lots of bugs stomped.
-
-*** Changes in EGCS 1.1:
-
-* Namespaces are fully supported. The library has not yet been converted
- to use namespace std, however, and the old std-faking code is still on by
- default. To turn it off, you can use -fhonor-std.
-
-* Massive template improvements:
- + member template classes are supported.
- + template friends are supported.
- + template template parameters are supported.
- + local classes in templates are supported.
- + lots of bugs fixed.
-
-* operator new now throws bad_alloc where appropriate.
-
-* Exception handling is now thread safe, and supports nested exceptions and
- placement delete. Exception handling overhead on x86 is much lower with
- GNU as 2.9.
-
-* protected virtual inheritance is now supported.
-
-* Loops are optimized better; we now move the test to the end in most
- cases, like the C frontend does.
-
-* For class D derived from B which has a member 'int i', &D::i is now of
- type 'int B::*' instead of 'int D::*'.
-
-* An _experimental_ new ABI for g++ can be turned on with -fnew-abi. The
- current features of this are more efficient allocation of base classes
- (including the empty base optimization), and more compact mangling of C++
- symbol names (which can be turned on separately with -fsquangle). This
- ABI is subject to change without notice, so don't use it for anything
- that you don't want to rebuild with every release of the compiler.
-
- As with all ABI-changing flags, this flag is for experts only, as all
- code (including the library code in libgcc and libstdc++) must be
- compiled with the same ABI.
-
-*** Changes in EGCS 1.0:
-
-* A public review copy of the December 1996 Draft of the ISO/ANSI C++
- standard is now available. See
-
- http://www.cygnus.com/misc/wp/
-
- for more information.
-
-* g++ now uses a new implementation of templates. The basic idea is that
- now templates are minimally parsed when seen and then expanded later.
- This allows conformant early name binding and instantiation controls,
- since instantiations no longer have to go through the parser.
-
- What you get:
-
- + Inlining of template functions works without any extra effort or
- modifications.
- + Instantiations of class templates and methods defined in the class
- body are deferred until they are actually needed (unless
- -fexternal-templates is specified).
- + Nested types in class templates work.
- + Static data member templates work.
- + Member function templates are now supported.
- + Partial specialization of class templates is now supported.
- + Explicit specification of template parameters to function templates
- is now supported.
-
- Things you may need to fix in your code:
-
- + Syntax errors in templates that are never instantiated will now be
- diagnosed.
- + Types and class templates used in templates must be declared
- first, or the compiler will assume they are not types, and fail.
- + Similarly, nested types of template type parameters must be tagged
- with the 'typename' keyword, except in base lists. In many cases,
- but not all, the compiler will tell you where you need to add
- 'typename'. For more information, see
-
- http://www.cygnus.com/misc/wp/dec96pub/template.html#temp.res
-
- + Guiding declarations are no longer supported. Function declarations,
- including friend declarations, do not refer to template instantiations.
- You can restore the old behavior with -fguiding-decls until you fix
- your code.
-
- Other features:
-
- + Default function arguments in templates will not be evaluated (or
- checked for semantic validity) unless they are needed. Default
- arguments in class bodies will not be parsed until the class
- definition is complete.
- + The -ftemplate-depth-NN flag can be used to increase the maximum
- recursive template instantiation depth, which defaults to 17. If you
- need to use this flag, the compiler will tell you.
- + Explicit instantiation of template constructors and destructors is
- now supported. For instance:
-
- template A<int>::A(const A&);
-
- Still not supported:
-
- + Member class templates.
- + Template friends.
-
-* Exception handling support has been significantly improved and is on by
- default. The compiler supports two mechanisms for walking back up the
- call stack; one relies on static information about how registers are
- saved, and causes no runtime overhead for code that does not throw
- exceptions. The other mechanism uses setjmp and longjmp equivalents, and
- can result in quite a bit of runtime overhead. You can determine which
- mechanism is the default for your target by compiling a testcase that
- uses exceptions and doing an 'nm' on the object file; if it uses __throw,
- it's using the first mechanism. If it uses __sjthrow, it's using the
- second.
-
- You can turn EH support off with -fno-exceptions.
-
-* RTTI support has been rewritten to work properly and is now on by default.
- This means code that uses virtual functions will have a modest space
- overhead. You can use the -fno-rtti flag to disable RTTI support.
-
-* On ELF systems, duplicate copies of symbols with 'initialized common'
- linkage (such as template instantiations, vtables, and extern inlines)
- will now be discarded by the GNU linker, so you don't need to use -frepo.
- This support requires GNU ld from binutils 2.8 or later.
-
-* The overload resolution code has been rewritten to conform to the latest
- C++ Working Paper. Built-in operators are now considered as candidates
- in operator overload resolution. Function template overloading chooses
- the more specialized template, and handles base classes in type deduction
- and guiding declarations properly. In this release the old code can
- still be selected with -fno-ansi-overloading, although this is not
- supported and will be removed in a future release.
-
-* Standard usage syntax for the std namespace is supported; std is treated
- as an alias for global scope. General namespaces are still not supported.
-
-* New flags:
-
- + New warning -Wno-pmf-conversion (don't warn about
- converting from a bound member function pointer to function
- pointer).
-
- + A flag -Weffc++ has been added for violations of some of the style
- guidelines in Scott Meyers' _Effective C++_ books.
-
- + -Woverloaded-virtual now warns if a virtual function in a base
- class is hidden in a derived class, rather than warning about
- virtual functions being overloaded (even if all of the inherited
- signatures are overridden) as it did before.
-
- + -Wall no longer implies -W. The new warning flag, -Wsign-compare,
- included in -Wall, warns about dangerous comparisons of signed and
- unsigned values. Only the flag is new; it was previously part of
- -W.
-
- + The new flag, -fno-weak, disables the use of weak symbols.
-
-* Synthesized methods are now emitted in any translation units that need
- an out-of-line copy. They are no longer affected by #pragma interface
- or #pragma implementation.
-
-* __FUNCTION__ and __PRETTY_FUNCTION__ are now treated as variables by the
- parser; previously they were treated as string constants. So code like
- `printf (__FUNCTION__ ": foo")' must be rewritten to
- `printf ("%s: foo", __FUNCTION__)'. This is necessary for templates.
-
-* local static variables in extern inline functions will be shared between
- translation units.
-
-* -fvtable-thunks is supported for all targets, and is the default for
- GNU/Linux with glibc 2.x (also called libc 6.x).
-
-* bool is now always the same size as another built-in type. Previously,
- a 64-bit RISC target using a 32-bit ABI would have 32-bit pointers and a
- 64-bit bool. This should only affect Irix 6, which was not supported in
- 2.7.2.
-
-* new (nothrow) is now supported.
-
-* Synthesized destructors are no longer made virtual just because the class
- already has virtual functions, only if they override a virtual destructor
- in a base class. The compiler will warn if this affects your code.
-
-* The g++ driver now only links against libstdc++, not libg++; it is
- functionally identical to the c++ driver.
-
-* (void *)0 is no longer considered a null pointer constant; NULL in
- <stddef.h> is now defined as __null, a magic constant of type (void *)
- normally, or (size_t) with -ansi.
-
-* The name of a class is now implicitly declared in its own scope; A::A
- refers to A.
-
-* Local classes are now supported.
-
-* __attribute__ can now be attached to types as well as declarations.
-
-* The compiler no longer emits a warning if an ellipsis is used as a
- function's argument list.
-
-* Definition of nested types outside of their containing class is now
- supported. For instance:
-
- struct A {
- struct B;
- B* bp;
- };
-
- struct A::B {
- int member;
- };
-
-* On the HPPA, some classes that do not define a copy constructor
- will be passed and returned in memory again so that functions
- returning those types can be inlined.
-
-*** The g++ team thanks everyone that contributed to this release,
- but especially:
-
-* Joe Buck <jbuck@synopsys.com>, the maintainer of the g++ FAQ.
-* Brendan Kehoe <brendan@cygnus.com>, who coordinates testing of g++.
-* Jason Merrill <jason@cygnus.com>, the g++ maintainer.
-* Mark Mitchell <mmitchell@usa.net>, who implemented member function
- templates and explicit qualification of function templates.
-* Mike Stump <mrs@wrs.com>, the previous g++ maintainer, who did most of
- the exception handling work.
-
-\f
-Copyright (C) 1997-2020 Free Software Foundation, Inc.
-
-Copying and distribution of this file, with or without modification,
-are permitted in any medium without royalty provided the copyright
-notice and this notice are preserved.
projects / gcc.git / commitdiff