Table of Contents
This section documents Sourcery G++ Lite changes for each released revision.
Improved NEON code generation for 0.0 constants. The compiler now generates better code for loading double float 0.0 constants on processors supporting NEON instructions.
Incorrect linker-generated functions. A bug that caused some linker-generated functions (including stubs to support interworking from ARM mode to Thumb mode and stubs to implement long branches) to jump to invalid offsets has been fixed.
Improved support for debugging RealView® programs with inlined functions . GDB has been enhanced to better handle debug information for inlined functions contained in binaries produced by the ARM RealView® compiler. Formerly, local variables in inner function scopes would become unavailable at calls to static inline functions. GDB now also includes inlined functions in the stack trace in binaries produced by RealView® versions earlier than 4.0. In addition, GDB's support for stepping over inline functions in programs built with such compilers has been improved.
Improved code generation for if
statements.
The compiler can now generate better code for if
statements when the then and else clauses contain similar code.
Thumb-2 backtrace fix. A GLIBC bug has been fixed that caused corrupt backtrace output while a system call was in progress. In rare cases, this bug could also cause multi-threaded programs to crash. Only Thumb-2 runtime libraries were affected.
Assembler encoding bug fixes.
Several bugs in the assembler have been fixed that
caused selection of incorrect encodings for some
instructions that have multiple encodings. The
incorrect encodings are not believed to have affected
runtime behavior but were not in conformance with
the canonical encodings specified by the ARM
ARM. The objdump
command has also
been fixed to decode such instructions correctly.
ARMv7-A performance improvements.
The compiler has been enhanced to produce faster code for the
ARM architecture, particularly for ARMv7-A cores, when compiling
using the -O2
option. This results in a
significant improvement in performance relative to CodeSourcery's
2009q3 releases.
Linker performance improvement. A bug in the linker that caused applications with many input files to link slowly has been fixed.
Weak symbols. An assembler bug has been fixed that caused incorrect code to be generated for references to weak symbols when a default definition is also provided in the same file.
ARM internal compiler error fix.
A bug that caused the error internal compiler error:
in get_arm_condition_code
when compiling code using
64-bit integers has been fixed.
Optimization of ARM NEON
vdupq_n*
intrinsics.
The compiler now generates better code for
vdupq_n*
intrinsics to load
particular constants.
Linker bug fix for --section-start
.
A linker bug that caused --section-start
to fail to work as documented if the section is defined
in multiple object files has been fixed.
GCC inline assembly bug fixes. A bug that caused NEON/VFP registers specified in the clobber list of inline assembly statements to be saved and restored incorrectly has been fixed. Another bug that caused incorrect code when double-precision or quad-precision registers were specified in the clobber list has also been fixed.
Assembler segmentation fault fix.
A bug has been fixed that caused the assembler
to crash when processing some data filling directives,
such as .fill 0, 0, 0
.
Linker bug with Cortex-A8 erratum fix.
A bug in the --fix-cortex-a8
linker option,
which is enabled by default when linking ARMv7-A objects,
has been fixed. The bug could cause the linker to generate
incorrect shared libraries.
Improved code generation for Cortex-A5.
The compiler has been enhanced to provide instruction
scheduling for Cortex-A5 cores. To take advantage of this,
use the -mcpu=cortex-a5
command-line option.
Improved support for debugging RealView® programs . GDB has been enhanced to handle some debug information contained in binaries produced by the ARM RealView® compiler. Formerly, GDB sometimes crashed on these programs and libraries.
Better use of NEON instructions on Cortex-A8. The compiler now generates better code when optimizing for the Cortex-A8 by being less eager to use NEON instructions.
Assembler segmentation fault fix. A bug has been fixed that caused the assembler to crash when assembling some Thumb-only instructions in ARM mode. The assembler now gives an error on all incorrect uses of Thumb-only instructions in ARM mode.
GCC internal compiler error.
A bug has been fixed that caused GCC to crash when
compiling some C++ code using templates at
-O2
or -O3
.
Backtracing through library functions. GLIBC has been improved to allow backtracing through system calls and other functions that formerly did not provide sufficient debug information to support this feature.
GCC internal compiler error with optimize
attribute.
A bug has been fixed that caused the compiler to crash
when invoked with the -O0
or
-O1
option on code using the
optimize
attribute to specify higher
optimization levels for individual functions.
C++ array initializer optimization. The compiler now generates better code for some non-constant array initializations in C++.
IPSR register.
A bug in the Sourcery G++ Debug Sprite that caused only five
bits of the M-profile IPSR
register to be
displayed in the debugger has been fixed.
Debugging preprocessed source code. A compiler bug has been fixed that caused debug output to erroneously contain the name of the intermediate preprocessed file.
Thumb-2 size optimization improvements.
The compiler has been enhanced to produce smaller code for the
ARM architecture, particularly for Thumb-2 mode, when compiling
using the -Os
option. This results in a
significant improvement in code size relative to CodeSourcery's
2009q3 releases.
GDB update. The included version of GDB has been updated to 7.0.50.20100218. This update adds numerous bug fixes and new features, including improved C++ language support, automatic caching of stack memory, and Position Independent Executable (PIE) support.
C++ name-mangling of va_list
.
The compiler no longer issues the mangling of
'va_list' has changed
warnings for references
to std::va_list
within system header files.
Static constructor and destructor ordering fixes. The linker now correctly ensures that static destructors with priorities are executed after destructors without priorities. Another linker bug that caused incorrect static constructor and destructor ordering with partial linking involved has been fixed.
Improved code generation for Cortex-A9.
The compiler has been enhanced to provide better instruction
scheduling for Cortex-A9 cores. To take advantage of this,
use the -mcpu=cortex-a9
command-line option.
Improved NEON code generation.
GCC's code generation for NEON targets
(e.g., when compiling with -mfpu=neon
)
has been improved.
In particular, the compiler can now make use of NEON
instructions for many 64-bit integer operations.
Indirect function call optimization. The instruction sequence used to implement calls via a function pointer has been improved to give better branch-prediction performance on some processors.
Thumb-2 function call optimization. The compiler has been enhanced to generate improved code on Thumb-2 targets for functions that return via calls to other functions.
vcvt
assembly bug fix.
A bug that caused vcvt.s32.f64
instructions
to be misassembled as vcvtr.s32.f64
has been
fixed.
Assembler fix for Thumb-2.
A bug that caused the assembler to reject some valid Thumb-2
strexd
instructions has been fixed.
Additional error checks in the assembler.
The assembler has been improved to perform a number of
additional checks for invalid inputs.
In particular, it now diagnoses additional invalid uses of the
PC and SP registers, as specified in the ARM documentation.
The assembler now also rejects invalid NEON alignment qualifiers,
such as vld1.8 {d0}, [r0, :128]
and vld1.8 {q0}, [r0, :256]
.
Branches between ARM and Thumb fix. An assembler bug that caused incorrect branches between ARM and Thumb code in different sections has been fixed.
Assembler segmentation fault fix.
A bug has been fixed that caused the assembler to crash
when processing code containing invalid Thumb-mode instructions
such as ldr r0, 0
. The assembler now produces an
error message in such cases.
NEON assembler fix.
The assembler now correctly handles the three-operand form of NEON
logic instructions, such as
vorr.i32 q0, q0, #0xff
Warning for deprecated instructions.
The assembler now issues warnings about uses of
swp
or swpb
instructions on architectures where they have been
deprecated.
Disassembler bug fix. A bug in the disassembler has been fixed that caused incorrect output for data objects, including literal pools and the interrupt vector.
Optimizer bug fix.
A bug in GCC that caused internal compiler errors
at -O2
or above has been fixed. The bug also
occurred at other optimization levels when
the -fpromote-loop-indices
command-line
option was used.
EGLIBC version 2.11.
Sourcery G++ Lite for ARM GNU/Linux now includes EGLIBC version 2.11
library which is based on GNU C Library version 2.11.
For more information about changes, see
http://www.eglibc.org/news#eglibc_2_11
.
Linker fix for data-only sections. A bug has been fixed that caused the linker to incorrectly mark parts of the output as containing code, rather than data, when linking data-only sections not explicitly tagged as such. The bug resulted in incorrect disassembly.
Linker relocation diagnostics. A bug that caused the linker to incorrectly diagnose overflows for some valid relocations has been fixed.
GDB asynchronous mode fix.
GDB can now be used from the command line in asynchronous mode
with remote targets. Previously, GDB did not accept user input
while asynchronous commands (such as
continue &
) were running.
Frame manipulation bug fix. A bug in GDB has been fixed that caused frame manipulation commands to report an internal error in some cases when used on arbitrary stack frames specified by an address.
Thumb-2 single stepping.
GDB now supports stepping through Thumb-2 conditionally
executed instructions. Earlier versions of GDB reported the
error Stepping through Thumb-2 IT blocks is not yet
supported
. A bug that caused GDB to lose control
when stepping over wide Thumb-2 branch instructions has also been
fixed.
Read watchpoints bug fix. A GDB bug has been fixed that caused watchpoints set to trigger on memory reads to be silently ignored in some cases.
Setting thread-specific breakpoints in GDB.
A bug in GDB has been fixed that caused a syntax error for
the break
*
command.
expression
thread
threadnum
Improved backtrace
function.
The backtrace
function can now
backtrace through C++ exception regions and through
functions marked throw()
.
Dynamic library unloading and destructor ordering.
A bug that caused dynamic libraries loaded
with dlopen
to remain loaded after
calling dlclose
to unload them, and thus their
destructors be called in the incorrect order has been fixed.
Optimized memcpy
.
The EGLIBC implementation of memcpy
has
been further optimized for ARM targets.
Thumb-2 multiply fix.
A bug that caused an invalid muls
instruction
to be generated in certain circumstances has been fixed. This
affected code compiled for Thumb-2, and resulted in an error
from the assembler.
Thumb-2 internal compiler error fix. A bug that caused an internal compiler error when building the QT library for Thumb-2 has been fixed.
Watchpoint fix. A bug in the Sourcery G++ Debug Sprite that sometimes prevented watchpoints on Cortex-M targets from functioning has been fixed.
Debug Sprite multiple connections fix.
When started with the -m
option,
the Sourcery G++ Debug Sprite no longer exits if the
connection to GDB is lost when sending a response.
Instead, it goes back to waiting for another connection.
Incorrect symbol addresses bug fix. A bug in the linker that caused it to assign incorrect addresses to symbols has been fixed. The bug occurred when the input objects contained sections not explicitly mentioned in the linker script and was most likely to occur when building the Linux kernel.
Backtracing through noreturn functions.
A compiler bug that made it impossible to obtain a backtrace
through functions declared with the noreturn
attribute has been fixed. This fix makes it possible for the
debugger to present a useful stack backtrace for applications
that call abort
.
GDB interrupt handling bug fix. A bug in GDB has been fixed that caused it to sometimes fail to indicate that the target had stopped after being interrupted. The bug affected clients using GDB's MI front end.
GDB and programs linked with
the --gc-sections
linker option.
GDB has been improved to better handle debug information
found in programs and libraries linked with
the --gc-sections
option. GDB formerly
selected the wrong debug information in some cases,
resulting in incorrect behavior when stepping over a
function or displaying local variables, for example.
GDB memory find bug fix.
A bug in GDB's find
command has been fixed.
The bug caused searches on large memory areas to fail or
report matches at incorrect addresses.
Improved assembler error checking. The assembler has been improved to perform additional checks for invalid inputs.
Internal compiler error fix.
A bug that caused an internal compiler error when using
-fno-omit-frame-pointer
to compile code for Thumb-2
has been fixed.
Out-of-range branch error. A compiler bug has been fixed that caused out-of-range branch errors from the assembler. The bug only affected code compiled in Thumb-2 mode.
ABI compliance.
The runtime libraries have been annotated with
Tag_ABI_align8_needed
and
Tag_ABI_align8_preserved
. This prevents errors
when linking Sourcery G++ support libraries with the ARM RealView® linker.
Increased speed of memcpy
and memmove
.
The performance of memcpy
and memmove
on NEON-enabled ARM
platforms is significantly improved, particularly when data
is being copied between mis-aligned addresses.
gdbserver
bug fix.
A bug has been fixed that caused gdbserver
to crash when debugging programs using thread-local storage
without other multi-threading features.
GDB crash fix. A GDB bug has been fixed that caused GDB to crash when unloading shared libraries or switching executables.
@
fix.
A bug has been fixed in the processing of
FILE
@
command-line options by GCC, GDB, and other tools.
The bug caused any options in
FILE
FILE
following a blank line
to be ignored.
Preprocessor error handling.
The preprocessor now treats failing to find a file referenced
via #include
as a fatal error.
Multi-threaded debugging fix.
A GDB bug has been fixed that caused the step
command to hang when debugging a multi-threaded program.
NEON improvements. The compiler now generates improved NEON vector code when copying memory or storing constants to memory using the NEON coprocessor. The compiler also generates better code for accessing data arrays that are not known to have 64-bit alignment. In addition, a bug that caused internal compiler errors when compiling for Thumb-2 with NEON enabled has been fixed, as has another bug that caused some vector shift NEON operations to be wrongly rejected.
ELF file corruption with strip
.
A bug that caused strip
to corrupt unusual
ELF files has been fixed.
GDB support for Cygwin pathnames. A bug in GDB's translation of Cygwin pathnames has been fixed.
Compiler errors with float32_t
.
A bug has been fixed that caused compiler errors when using the
float32_t
type from arm_neon.h
.
gdbserver
multi-threaded debugging fix.
A bug has been fixed that prevented
gdbserver
from exiting after debugging a
multi-threaded program.
Thumb-2 position-independent executables. A bug that caused position-independent executables to fail to run correctly has been fixed. The bug only affected code compiled for Thumb-2 mode.
Support for ARM Cortex-A5 cores.
Sourcery G++ now includes basic support for ARM Cortex-A5 cores.
Use the -mcpu=cortex-a5
command-line option.
Static variables and asm
statements bug fix.
A bug in GCC that caused functions containing static variables
and asm
statements to be miscompiled
at -O2
or above has been fixed. The bug also
occurred at other optimization levels when
the -fremove-local-statics
command-line
option was used.
Warnings for naked functions.
A compiler bug that resulted in incorrect warnings about
missing return statements in non-void functions declared with
the naked
attribute has been fixed.
Optimizer bug fix.
A bug in GCC that caused functions with complex loop nests to
be miscompiled at -O2
or above has been
fixed. The bug also occurred at other optimization levels
when the -fpromote-loop-indices
command-line
option was used.
VFPv4 support.
Sourcery G++ now includes support for VFPv4, VFPv4-D16 and
NEON-VFPv4 coprocessors. Use the -mfpu=vfpv4
,
-mfpu=vfpv4-d16
or
-mfpu=neon-vfpv4
options, respectively.
GCC internal compiler error. A bug has been fixed that caused the compiler to crash when optimizing code that casts between structure types and the type of the first field.
ELF Program Headers.
The linker now better diagnoses errors in the usage of
FILEHDR
and PHDRS
keywords in PHDRS
command of linker
scripts. Refer to the linker manual for more information.
VFP half-precision extensions.
Sourcery G++ now includes support for VFP coprocessors with
half-precision floating-point extensions. This can be enabled
with the -mfpu=vfpv3-d16-fp16
or
-mfpu=vfpv3-fp16
command-line options.
Linux kernel headers update. Linux kernel header files have been updated to version 2.6.30.
ARM VFP assembler bug fix.
The assembler now correctly assembles the
vmls
, vnmla
and
vnmls
mnemonics. Previously these were
incorrectly assembled to different instructions.
Improved optimization for ARM.
GCC now automatically enables loop unrolling and
-fpromote-loop-indices
when
-O2
or -O3
is specified.
Loop unrolling is limited at -O2
to
control code growth. These changes improve performance by
more than 5%.
VFP assembly mnemonics.
The assembler now accepts unified assembly mnemonics for
VFP instructions (e.g. VADD.f32 s0, s0
)
in legacy syntax mode.
Register corruption bug in setjmp
and longjmp
.
A bug that could cause register corruption in
setjmp
and longjmp
has been fixed.
Optimizer improvements. When optimizing for speed, the compiler now uses improved heuristics to limit certain types of optimizations that may adversely affect both code size and speed. This change also makes it possible to produce better code when optimizing for space rather than speed.
Improved optimization for Thumb-2.
GCC now supports instruction scheduling for Thumb-2 code.
This optimization is enabled when compiling with
-O2
, -O3
, or
-Os
, and can improve performance
substantially.
Linking objects built without -fPIC
into shared libraries.
The linker now gives an error for attempts to link object
files built without -fPIC
or
-fpic
into shared libraries when those
objects use the ARMv7 MOVW
and
MOVT
instructions in ways that are unsafe
in a shared library. Previously it built a shared library
that behaved incorrectly when used.
GDB update. The included version of GDB has been updated to 6.8.50.20090630. This update adds numerous bug fixes and new features, including support for multi-byte and wide character sets and improved C++ template support.
New assembler directive .inst
.
The assembler now accepts the new .inst
directive to generate an instruction from its integer encoding.
GDB and third-party compilers. Some bugs that caused GDB to crash when debugging programs compiled with third-party tools have been fixed. These bugs did not affect programs built with Sourcery G++.
Remote debugging hardware watchpoint bug fix. A GDB bug has been fixed that caused hardware watchpoint hits to be incorrectly reported in some cases.
Internal error in assembler.
An assembler bug that caused an internal error when
.thumb
or .arm
appears after an
invalid instruction has been fixed.
GDB internal warning fix.
A GDB bug has been fixed that caused warnings of the form
warning: (Internal error: pc
.
address
in read in psymtab, but not in symtab.)
Improved bit counting operation.
The __builtin_ctz
built-in function,
which returns the number of trailing zero bits in a value,
has been improved to use a shorter instruction sequence for
ARMv6T2 and later.
Out-of-range branch errors.
A Thumb-2 code generation defect in the compiler that caused
branch out of range
errors from the
assembler has been eliminated.
Binutils update. The binutils package has been updated to version 2.19.51.20090709 from the FSF trunk. This update includes numerous bug fixes.
Linker fix. The linker now correctly processes references to undefined local symbols. Such references are treated the same as references to undefined global symbols. Usually object files contain no such references, as they can never be satisfied.
Assembler validation improvements.
The assembler now issues a warning when a section finishes with
an unclosed IT instruction block at the end of the input file.
It also now rejects unwinding directives that appear
outside of a .fnstart
/.fnend
pair.
Additionally, 32-bit Thumb instructions are now correctly rejected
when assembling for cores that do not support these instructions.
Assembler validations fix.
A bug in the assembler that caused some addw
and
subw
instructions with SP or PC as operand to be
wrongly rejected has been fixed.
-mauto-it
assembler option replaced with
-mimplicit-it
.
The -mauto-it
command-line option to the
assembler has been replaced with a more general
-mimplicit-it
option to control the behavior
of the assembler when conditional instructions appear outside
an IT instruction block. If you were previously using
-mauto-it
, you should now use
-mimplicit-it=always
. Other
-mimplicit-it
modes allow you to separately
control implicit IT instruction insertion behavior in ARM
and Thumb-2 code. For more information, refer to the
assembler manual.
In addition to renaming the option,
a number of bugs in the implicit IT generation have been fixed.
Linker failure with Cortex-A8 erratum fix.
A bug in the --fix-cortex-a8
linker option
has been fixed. The bug caused the linker either to
produce a bad value
error, or to
silently generate an incorrect executable.
Debug information for variadic functions. A compiler bug that resulted in incorrect debug information for functions with variable arguments has been fixed.
Code generation improvements. The compiler has been changed to make better use of VFP registers in mixed integer and floating-point code, resulting in faster code.
Register variable corruption.
A compiler bug has been fixed that caused incorrect code to be
generated when the frame pointer or other special-use registers
are used as explicit local register variables, introduced via the
asm
keyword on their declarations.
Startup code debugging fixes.
Two GDB bugs have been fixed that caused errors when
debugging startup code. One bug caused an internal error
message; the other caused the error Cannot find
bounds of current function
.
Assembler fix for mixed Thumb and ARM mode. A bug in the assembler has been fixed where mapping symbols were sometimes incorrectly placed at section boundaries. This could lead to incorrect disassembly in some cases.
C++ exception matching.
A C++ conformance defect has been fixed. According to
clause 15.3 of the standard, given a derived class
D
with base B
, a thrown D
*
object is not caught by a handler with type B
*&
(that is, a reference to pointer B
).
The compiler formerly treated this case incorrectly as if
the handler had type B *
, which does catch
D *
.
-fremove-local-statics
optimization.
The -fremove-local-statics
optimization is
now enabled by default at -O2
and higher
optimization levels.
Elimination of spurious warnings about NULL
.
The C++ compiler no longer issues spurious warnings about
comparisons between pointers to members and
NULL
.
Vectorizer improvements.
The compiler now generates improved code for accesses to static
nested array variables
(e.g. static int foo[8][8];
).
EGLIBC version 2.10.
Sourcery G++ Lite for ARM GNU/Linux now includes EGLIBC version 2.10
library which is based on GNU C Library version 2.10.
For more information about changes, see
http://www.eglibc.org/news#eglibc_2_10
.
Configuration file required for Debug Sprite. When invoking the Sourcery G++ Debug Sprite from the command line, it is now required to specify a board configuration file argument. This change eliminates a source of confusion and errors resulting from accidental omission of the configuration file argument, since recent improvements to debugger functionality depend on properties specified in the configuration file. Refer to Chapter 5, “Sourcery G++ Debug Sprite” for more details on invoking the Sourcery G++ Debug Sprite from the command line.
Invalid relocations in startup code. A bug that caused invalid relocations to be present in the C library startup code has been fixed. This bug caused problems when using these objects with third-party tools.
GCC version 4.4.1.
Sourcery G++ Lite for ARM GNU/Linux is now based on GCC version 4.4.1.
For more information about changes from GCC version 4.3 that was
included in previous releases, see
http://gcc.gnu.org/gcc-4.4/changes.html
.
Watchpoint support. The Sourcery G++ Debug Sprite now implements watchpoints on all currently-supported debugging devices.
Linker map address sorting.
The map generated by the linker -Map
option
now lists symbols sorted by address.
Assembler fix.
The assembler now correctly diagnoses a missing operand to
bl
and blx
instructions.
Previously, incorrect code was silently generated.
Internal compiler error with Cortex-A9.
A bug has been fixed that caused internal compiler errors when
compiling with -mcpu=cortex-A9
.
GDB finish
internal error.
A bug has been fixed that caused a GDB internal error when
using the finish
command. The bug occurred
when debugging optimized code.
GDB backwards compatibility fix. A bug has been fixed that caused GDB to crash when loading symbols from binaries built by very old versions of GCC.
Overloaded function resolution. The C++ compiler now correctly diagnoses an error when the second operand of a comma expression is an unresolved set of overloaded functions. Previously, it incorrectly used the context of the comma expression to resolve the function.
Fix for backtrace
function in dynamically-linked executables.
The backtrace
function now reports
backtraces for dynamically-linked executables. Previously,
this function worked only with statically-linked
executables, i.e., executables linked with
-static
.
Pointer-to-member functions.
A bug has been fixed that caused the C++ compiler to crash
when compiling a pointer-to-member function reference
without an explicit &
operator. This
syntax is allowed only when the
-fms-extensions
command-line option is
used.
Assembler fix for -mauto-it
.
A bug in the assembler that caused incorrect assembly
of branches has been fixed. The bug only occurred when
automatically generating IT instructions using
-mauto-it
.
Fix for dlopen
in statically-linked executables.
A bug has been fixed that made statically-linked programs
crash when calling dlopen
with
RTLD_GLOBAL
to request global availability
of symbols from the shared module.
Overlay sections.
arm-none-linux-gnueabi-readelf
now correctly recognizes
section headers for ARM_DEBUGOVERLAY
and ARM_OVERLAYSECTION
sections.
Linker bug fix.
A bug that caused the linker to crash when
.ARM.exidx
sections were discarded by a
linker script has been fixed.
Incorrect placement of linker-generated functions. A bug that caused some linker-generated functions (including stubs to support interworking from ARM mode to Thumb mode and stubs to avoid processor errata) to be placed in data sections has been fixed.
New option for automatically generating IT blocks.
The assembler now allows use of conditional Thumb-2 instructions without
requiring explicit IT instructions.
Use the -mauto-it
command-line option to enable this
automatic generation of IT instructions.
Optimized memcpy
.
The implementation of memcpy
has
been optimized to increase performance on ARM targets that
support prefetch instructions.
Optimized memory and string routines.
The implementations of memcpy
,
memset
, strcmp
,
strcpy
, and strlen
have been optimized to increase performance on ARM targets.
Reduced compilation time. Compilation and build times when using Sourcery G++ Lite are now slightly faster. This performance improvement is the result of building the compilers and other host tools with a recent version of Sourcery G++, rather than an older GCC version.
Support for GLIBC backtrace
function.
Sourcery G++ Lite now supports the GLIBC backtrace
function on ARM GNU/Linux targets.
For more information, see Section 3.7, “GLIBC Backtrace Support”.
Assembler bug fix.
A bug in the assembler that caused duplicate and missing
mapping symbols has been fixed. The bug caused incorrect
objdump
output and incorrect
byte-swapping for BE8 configurations.
Stack backtracing and C++ exception handling.
Improvements have been made to the linker in support of
C++ runtime exception handling and stack backtracing.
A problem that caused crashes during the backtrace of C routines
that were not compiled with the -fexceptions
option has been fixed.
In addition, the linker generates more compact stack unwinding
tables which can lead to smaller executables.
Incorrect linker-generated functions.
A bug that caused some linker-generated functions (such as stubs
to support interworking from ARM mode to Thumb mode) to contain only
nop
instructions instead of correct code sequences
has been fixed.
Assembler diagnostics for invalid instructions.
The assembler now issues diagnostics for invalid
ADR
and ADRL
instructions.
Formerly, these invalid instructions were silently mis-assembled.
This assembler bug did not affect correct code.
Sprite's failure to reset the target.
A bug has been fixed that sometimes caused the Sourcery G++
Debug Sprite to fail to reset the target when using the
multiple sequential connection feature (enabled via the
-m
command-line option). This problem was
specific to running the Debug Sprite on Microsoft Windows
hosts.
Disassembler bug fix. A bug has been fixed that caused incorrect disassembly of some object files with multiple sections whose symbol tables included symbols in the middle of functions. These typically resulted from hand-written assembly.
Linker crash with very large applications.
A linker bug that caused a crash when linking very large
applications with the --fix-cortex-a8
command-line option has been fixed.
arm-none-linux-gnueabi-objcopy
bug fix.
A bug has been fixed that caused
arm-none-linux-gnueabi-objcopy
to issue an error
when generating output in the Intel HEX format and using
--change-section-lma
to change section
addresses.
Linker script search path.
The bug in the linker has been fixed that caused it not to
follow its documented behavior for searching for linker
scripts named with the -T
option. Now
scripts are looked up first in the current directory, then
in library directories specified with -L
command-line options, and finally in the default system
linker script directory.
Errors when inserting breakpoints.
A GDB bug has been fixed that caused errors of the form
`
when setting a breakpoint on function
' found in
filename
psymtab but not in symtab
function
.
This error commonly occurred when setting breakpoints on functions
provided by the C library.
Cortex-A8 erratum workaround enabled for ARMv7-A.
The workaround for the erratum in Cortex-A8 processors mentioned
below is now enabled by default if you are targeting the ARMv7-A
architecture profile. The workaround can be disabled by passing
the --no-fix-cortex-a8
option to the linker.
Internal compiler error when optimizing.
A bug has been fixed that caused internal compiler
error: in build2_stat
when compiling.
Erratum workaround for Cortex-A8 processors.
The linker now implements a workaround for an erratum
in Cortex-A8 processors. If you are targeting an
affected part and wish to use the workaround, pass the
--fix-cortex-a8
option to the linker.
Please contact ARM for further details of the erratum.
Maximum code alignment increased.
The maximum allowed code alignment has been increased from
32 to 64 bytes. This change affects the .p2align
and .align
assembler directives and the
-falign-functions
GCC option.
Corruption of block-scope variables. A compiler optimization bug that sometimes caused corruption of stack-allocated variables has been fixed. The bug affected variables declared in a local block scope in functions containing multiple non-overlapping lexical block scopes, a technique commonly used by programmers to reduce stack frame size. In some rare cases, other optimizations performed by the compiler were ignoring the local extent of such block-scope variables.
ARM EABI attributes. An assembler bug that resulted in some object files generated from hand-written assembly being incorrectly tagged as using VFP instructions has been fixed. This tagging was harmless for objects linked with Sourcery G++ tools and libraries, but may have affected third-party tools and libraries.
Incorrect code when using -falign-labels
.
A bug that caused the compiler to generate incorrect code
for switch
statements when the
-falign-labels
option is used has been fixed.
ARMv4T library selection.
Compiler options such as -mcpu=arm740t
,
specifying an ARMv4T CPU, now cause the compiler to link
with the ARMv4T libraries without
requiring -march=armv4t
to be specified as
well.
Core files in GDB.
A bug in GDB has been fixed that caused incorrect values for
CPSR (the status register) to be displayed when debugging
core files. In some cases, this bug could also cause the
gcore
command to crash GDB.
Loop optimization improvements.
A new option, -fpromote-loop-indices
, has
been added to the compiler. Specifying this option enables an
optimization that improves the performance of loops with index
variables of integer types narrower than the target machine
word size, such as char
or short
.
This optimization also applies to int
on 64-bit
targets.
Support for VFP and Advanced SIMD (NEON) register display.
The Sourcery G++ debugger can now display VFP and Advanced
SIMD registers when debugging Linux applications with
gdbserver
. This may require a kernel
patch; see Section 3.4, “Target Kernel Requirements” for details.
Extraneous linker error messages.
A linker bug that caused extraneous error messages of the form
Dwarf Error: Offset (507) greater than or equal to
.debug_str size (421).
has been corrected. This bug did not
affect the correctness of output binaries.
Assembler marking of data.
Data generated using the assembler directives
.ascii
, .asciz
,
.dc.d
, .dc.s
, .dc.x
,
.dcb
, .dcb.b
, .dcb.d
,
.dcb.l
, .dcb.s
,
.dcb.w
, .dcb.x
, .ds
,
.ds.b
, .ds.d
, .ds.l
,
.ds.p
, .ds.s
, .ds.w
,
.ds.x
, .double
,
.fill
, .float
,
.incbin
, .single
,
.space
, .skip
,
.string
, .string8
,
.string16
, .string32
,
.string64
, and .zero
is now
correctly marked by the assembler as data rather than code.
This fixes incorrect byte-swapping of such data when linking
for BE8 configurations.
VFP ABI support. Sourcery G++ now supports the VFP variant of the Procedure Call Standard for the ARM® Architecture (AAPCS) in addition to the default soft-float ABI. The VFP ABI uses VFP registers to pass function arguments and return values, resulting in faster floating-point code. Code compiled with the VFP ABI is not compatible with the soft-float ABI libraries provided with Sourcery G++ Lite; however, VFP ABI libraries for little-endian ARM v7-A processors are now available as add-ons for Sourcery G++ Professional Edition. For further information about floating-point compiler, ABI and library support in Sourcery G++, refer to Section 3.8.1, “Enabling Hardware Floating Point”.
Improved vectorization.
Automatic vectorization for NEON now uses the fused
multiply-add (VMLA
) and fused
multiply-subtract (VMLS
) instructions.
These fused instructions are faster than the equivalent
two-instruction sequence consisting of a multiply followed
by an add or subtract.
GDB quit
error.
A bug in GDB has been fixed that
caused quit
to report Quitting:
You can't do that without a process to debug.
when
debugging a core dump file.
Out-of-bounds accesses to stack arrays.
A bug has been fixed that caused internal compiler errors
when some code involving out-of-bounds accesses to
stack-allocated arrays was compiled with
the -mthumb
option. Such code is not valid
C; although it is now accepted by the compiler and no
diagnostic is issued, it has undefined behavior if executed.
Thread cancellation in aio_suspend
.
A bug in the Thumb-2 version of
aio_suspend
has been fixed that caused
programs to crash if the calling thread was canceled.
Linking big-endian programs for ARMv7-A.
When linking for ARMv7-A targets with -mbig-endian
,
Sourcery G++ now implicitly assumes BE8 mode, rather than BE32.
GCC version 4.3.3.
Sourcery G++ Lite for ARM GNU/Linux is now based on GCC version 4.3.3.
This is a bug fix update to GCC.
For more information about changes from GCC version 4.3.2 that was
included in previous releases, see
http://gcc.gnu.org/gcc-4.3/changes.html
.
Improved NOP generation for Thumb-2 cores. The assembler now generates Thumb-2/ARMv6K architectural NOP instructions when alignment padding is required in code sections.
ARM atomic memory operations.
Support has been added for atomic memory operations in ARM
Linux applications via built-in functions (for example,
__sync_fetch_and_add
). Please refer to the GCC
manual (Atomic Builtins) for further information.
Internal compiler error with -O3
or -fpredictive-commoning
.
A bug has been fixed that caused internal compiler errors
when compiling some code with -O3
or -fpredictive-commoning
.
CS3 board and processor support. CS3 board and processor support has been cleaned up to remove entries that are not appropriate for or supported by Sourcery G++ Lite on ARM GNU/Linux targets. This includes processors for which Sourcery G++ Lite does not include appropriate run-time libraries. In addition, CS3 support files for boards and processors that do not have an MMU to support running the Linux kernel have been removed. These changes are intended to simplify processor and board selection.
C++ named operators bug fix.
A bug has been fixed that caused the compiler to crash in
some cases when the C++ operators and_eq
,
bitand
, bitor
, compl
,
not_eq
, or_eq
and
xor_eq
were used in contexts where the
preprocessor converts their names to strings.
Debug information for anonymous structure types.
A GCC bug in the generation of debug information for anonymous structure
types in C++ code has been fixed. The bug caused
printing the type information for such structures in the debugger (via the
ptype
command) to fail with an error message.
timer_delete
bug.
A bug has been fixed that caused some programs to crash or
hang after calling timer_delete
.
Linker errors on non-ELF input.
A bug has been fixed that caused internal errors from the
linker when linking non-ELF input files (with the
-b
or --format
linker
options).
Undefined weak references in shared libraries. A linker bug has been fixed affecting calls from Thumb code in shared libraries to functions that are undefined weak references when the shared library is linked. Such calls executed as nops whether or not the functions were defined at run time. This affected thread-related code in the Thumb-2 versions of the standard C++ library provided with Sourcery G++, causing some multithreaded C++ programs to crash.
Improved code generation. The compiler has been improved to generate better code for an integer multiplication whose result feeds into an addition.
Installer fails during upgrade. The Sourcery G++ installer for Microsoft Windows hosts could fail during an upgrade while waiting for the previous version to be uninstalled. This bug has been fixed.
Performance improvements. Tuning parameters for ARM code generation have been adjusted to improve performance of the generated code.
Uninstaller removed by upgrade. The uninstaller could be incorrectly deleted during an upgrade on Microsoft Windows hosts. This bug has been fixed.
Remote debugging connection auto-retry.
The target remote
command within GDB now uses
a configurable auto-retry timeout when establishing TCP connections.
This is useful in avoiding race conditions when the remote
GDB stub or GDB server is launched simultaneously with GDB.
The auto-retry behavior is enabled by default; refer to the
GDB manual for details.
CMP
Thumb-2 instruction.
The assembler no longer issues an error about
CMP
instructions in which the second
argument is the stack pointer (r13
), as
these are valid instructions. However, use of the stack
pointer in this context is deprecated in the current ARM
architecture specification and the assembler now warns about
the deprecated use.
DMB
, DSB
, and
ISB
instructions on ARMv6-M.
The assembler now accepts the DMB
,
DSB
, and ISB
instructions on ARMv6-M CPUs, including Cortex-M0 and
Cortex-M1. These instructions were incorrectly rejected on
these CPUs in previous releases.
Thumb half-precision floating point bug fix. A compiler bug has been fixed that formerly caused incorrect code to be generated in Thumb mode for functions using half-precision floating-point constants. The bug did not affect Thumb-2 code.
Improved code generation. The compiler has been improved to generate better code for integer multiplication by certain constants.
Thumb-2 switch
code generation bug fix.
A bug has been fixed that caused incorrect Thumb-2 code to
be generated for some switch
statements.
This affected code in the libraries provided with
Sourcery G++ that handles cleanup
attributes
and POSIX thread cancellation.
Internal compiler errors when optimizing. A defect that occasionally caused internal compiler errors when partial redundancy elimination (PRE) optimization was enabled has been corrected.
Install directory pathnames. Bugs in the install and uninstall scripts for Linux hosts that caused errors or incorrect behavior when the Sourcery G++ install directory pathname contains whitespace characters have been fixed.
Internal compiler error with large NEON types. A bug has been fixed that caused internal compiler errors when compiling code using NEON types at least 32 bytes wide.
Temporary files on Microsoft Windows.
On Microsoft Windows hosts, Sourcery G++ Lite now uses the standard
Windows algorithm to choose the directory in which to place
temporary files. This change eliminates a crash that
occurred if none of the TEMP
,
TMP
, or TMPDIR
variables were
set to a suitable directory.
Vectorized shift fix.
A bug has been fixed that caused incorrect code for loops
containing a right shift by a constant. The bug affected
code compiled with -mfpu=neon
and loop vectorization enabled with -O3
or
-ftree-vectorize
.
Incorrect code for nested functions. A bug in GCC that caused the compiler to generate incorrect code for nested functions has been fixed. The bug resulted in incorrect stack alignments in the affected functions.
Binutils update. The binutils package has been updated to version 2.19.51.20090205 from the FSF trunk. This update includes numerous bug fixes.
sched_setaffinity
bug fix.
A bug has been fixed that caused the Thumb-2 version of
sched_setaffinity
to fail
inappropriately with EFAULT
.
ARM build attributes conformance improvements. Several ARM EABI 2.07 conformance issues relating to the handling of build attributes in the assembler and linker have been fixed. All build attribute types are now recognized, and can now be declared by name, in addition to by number. Support for merging attributes in the linker has been improved, and the linking of incompatible objects is now detected and rejected in more cases.
Internal compiler error
with -fremove-local-statics
.
An internal compiler error that occurred when using
the -fremove-local-statics
option has been
fixed. The error occurred when compiling code with
function-local static
array or structure
variables.
GDB update. The included version of GDB has been updated to 6.8.50.20081022. This update includes numerous bug fixes.
Linker crash on incompatible input files. Some third-party compilers, including ARM RealView® 4.0, produce a build attribute marking output files that are not compatible with the ABI for the ARM Architecture. This attribute sometimes caused the linker to crash. The linker now correctly issues an error message.
Bug fix for assembly listing.
A bug that caused the assembler to produce corrupted
listings (via the -a
option) on Windows
hosts has been fixed.
Optimizer bug fix.
A bug that caused an unrecognizable insn
internal compiler error when compiling at optimization levels
above -O0
has been fixed.
VFP compiler fix.
A compiler bug that resulted in
internal compiler error: output_operand: invalid expression as operand
when generating VFP code has been fixed.
GDB display of source. A bug has been fixed that prevented GDB from locating debug information in some cases. The debugger failed to display source code for or step into the affected functions.
Bug fix for libSegFault.so
.
Binaries linked with libSegFault.so
now
produce a correct backtrace when a segmentation fault
occurs. Formerly, the location of the fault was shown
incorrectly.
GDB segment warning.
Some compilers produce binaries including uninitialized data
regions, such as the stack and heap. GDB incorrectly
displayed the warning Loadable segment
"
for such binaries; the warning has now
been fixed.
name
" outside of ELF
segments
Misaligned NEON memory accesses.
A bug has been fixed that caused the compiler to use aligned
NEON load/store instructions to access misaligned data when
autovectorizing certain loops. The bug affected code compiled
with -mfpu=neon
and loop vectorization enabled
with -O3
or -ftree-vectorize
.
Sprite crash on error. A bug has been fixed which sometimes caused the Sourcery G++ Debug Sprite to crash when it attempted to send an error message to GDB.
Persistent remote server connections.
A GDB bug has been fixed that caused the target
extended-remote
command to fail to tell the
remote server to make the connection persistent across
program invocations.
Definition of va_list
.
In order to conform to the ABI for the ARM Architecture, the
definition of the type of va_list
(defined in
stdarg.h
) has been
changed. This change impacts only the mangled names of C++
entities. For example, the mangled name of a C++ function
taking an argument of type va_list
, or
va_list *
, or another type involving
va_list
has changed. Since this is an
incompatible change, you must recompile and relink any
modules defining or using affected
va_list
-typed entities.
Thumb-2 assembler fixes.
The Thumb-2 encodings of QADD
,
QDADD
, QSUB
, and
QDSUB
have been corrected. Previous versions
of the assembler generated incorrect object files for these
instructions. The assembler now accepts the
ORN
, QASX
, QSAX
,
RRX
, SHASX
, SHSAX
,
SSAX
, USAX
, UHASX
,
UQSAX
, and USAX
mnemonics. The
assembler now detects and issues errors for invalid uses of
register 13 (the stack pointer) and register 15 (the program
counter) in many instructions.
Printing casted values in GDB.
A GDB bug that caused incorrect output for expressions
containing casts, such as in the
print *(Type *)ptr
command, has been fixed.
Bug fix for objcopy/strip.
An objcopy bug that corrupted COMDAT groups when creating new
binaries has been fixed. This bug also affected
strip -g
.
Improved support for debugging RealView® objects . GDB support for programs compiled by the ARM RealView® compiler has been improved.
Binutils support for DWARF Version 3.
The addr2line
command now supports
binaries containing DWARF 3 debugging information. The
ld
command can display error messages
with source locations for input files containing DWARF 3
debugging information.
NEON improvements.
Several improvements and bug fixes have been made to the
NEON Advanced SIMD Extension support in GCC. A problem that
caused the autovectorizer to fail in some circumstances has
been fixed. Also, many of the intrinsics available via the
arm_neon.h
header file
now have improved error checking for out-of-bounds arguments,
and the vget_lane
intrinsics that return signed
values now produce improved code.
NEON compiler fix.
A compiler bug that resulted in incorrect NEON code being
generated has been fixed. Typically the incorrect code
occurred when NEON intrinsics were used inside small
if
statements.
Connecting to the target using a pipe.
A bug in GDB's
target remote |
command has been fixed. When launching the specified
program
program
failed, the bug caused
GDB to crash, hang, or give a message
Error: No Error
.
Mixed-case NEON register aliases.
An assembler bug that prevented NEON register aliases from being
created with mixed-case names using the .dn
and
.qn
directives has been fixed. Previously only
aliases created with all-lowercase or all-uppercase names
worked correctly.
Janus 2CC support.
GCC now includes a work-around for a hardware bug in Avalent
Janus 2CC cores. To compile and link for these cores, use
the -mfix-janus-2cc
compiler option. If
you are using the linker directly use the
--fix-janus-2cc
linker option.
ARM exception handling bug fix. A bug in the runtime library has been fixed that formerly caused throwing an unexpected exception in C++ to crash instead of calling the unexpected exception handler. The bug only affected C++ code compiled by non-GNU compilers such as ARM RealView®.
Mangling of NEON type names.
A bug in the algorithm used by the C++ compiler for mangling
the names of NEON types, such as int8x16_t
, has
been fixed. These mangled names are used internally in
object files to encode type information in addition to the
programmer-visible names of the C++ variables and functions.
The new mangled name encoding is more compact and conforms
to the ARM C++ ABI.
Errors after loading the debugged program.
An intermittent GDB bug has been fixed. The bug could cause
a GDB internal error
after the load
command.
Half-precision floating point.
Sourcery G++ now includes support for half-precision floating point
via the __fp16
type in C and C++. The compiler can
generate code using either hardware support or library routines.
For more information, see Section 3.8.3, “Half-Precision Floating Point”.
GDB update.
The included version of GDB has been updated to
6.8.50.20080821. This update adds numerous bug fixes and
new features, including support for decimal floating point,
improved Thumb mode
support, the new find
command to
search memory, the new /m
(mixed
source and assembly) option to the
disassemble
command, and the new
macro define
command to define C
preprocessor macros interactively.
Uppercase operands to IT instructions.
The assembler now accepts both uppercase and lowercase operands
for the IT
family of instructions.
NEON autovectorizer fix.
A compiler bug that caused generation of bad VLD1
instructions has been fixed. The bug affected code compiled with
-mfpu=neon -ftree-vectorize
.
Remote debugging improvements.
The gdbserver
utility now supports a more
efficient communications protocol that can reduce latency during
remote debugging. The protocol optimizations are enabled
automatically when gdbserver
operates over
a TCP connection. Refer to the GDB manual for more information.
Output files removed on error. When GCC encounters an error, it now consistently removes any incomplete output files that it may have created.
ARMv7 offset out of range errors.
An assembler bug that resulted in
offset out of range
errors when compiling for
ARMv7 processors has been fixed.
Thumb-2 MUL
encoding.
In Thumb-2 mode, the assembler now encodes MUL
as a 16-bit instruction (rather than as a 32-bit
instruction) when possible. This fix results in smaller
code, with no loss of performance.
ARM C++ ABI utility functions.
Vector utility functions required by the ARM C++ ABI no
longer crash when passed null pointers. The affected
functions are __aeabi_vec_dtor_cookie
,
__aeabi_vec_delete
,
__aeabi_vec_delete3
, and
__aeabi_vec_delete3_nodtor
.
In addition, on GNU/Linux systems, the ARM C++ ABI utility
functions are now exported from the
libstdc++.so
shared library.
These functions are not intended for use by application
programmers; they are only called by compiler-generated
code. They are not presently used by the GNU C++ compiler,
but are used by some other compilers, including ARM's
RealView®
compiler.
GCC version 4.3.2.
Sourcery G++ Lite for ARM GNU/Linux is now based on GCC version 4.3.2.
For more information about changes from GCC version 4.2 that was
included in previous releases, see
http://gcc.gnu.org/gcc-4.3/changes.html
.
Smaller Thumb-2 code.
When optimizing for size (i.e., when -Os
is
in use), GCC now generates the 16-bit MULS
Thumb-2 multiply instruction instead of the 32-bit
MUL
instruction.
Thumb-2 RBIT
encoding.
An assembler bug that resulted in incorrect encoding of the
Thumb-2 RBIT
instruction has been fixed.
Sprite communication improvements. The Sourcery G++ Debug Sprite now uses a more efficient protocol for communicating with GDB. This can result in less latency when debugging, especially when running the Sprite on a remote machine over a network connection.
Marvell Feroceon compiler bug fix. A bug that caused an internal compiler error when optimizing for Marvell Feroceon CPUs has been fixed.
Misaligned accesses to packed structures fix. A bug that caused GCC to generate misaligned accesses to packed structures has been fixed.
Bug fix for objdump on Windows.
An objdump bug that caused the -S
option
not to work on Windows in some cases has been fixed.