Appendix A. Sourcery CodeBench Lite Release Notes

This appendix contains information about changes in this release of Sourcery CodeBench Lite for MIPS ELF. You should read through these notes to learn about new features and bug fixes.

Table of Contents

A.1. Changes in Sourcery CodeBench Lite for MIPS ELF

A.1. Changes in Sourcery CodeBench Lite for MIPS ELF

This section documents Sourcery CodeBench Lite changes for each released revision.

A.1.1. Changes in Sourcery CodeBench Lite 2013.05-35

C++ exception handling format.  The C++ exception handling format has been changed to fix a defect in the specification. The new format is not backwards-compatible with code produced by Sourcery CodeBench beginning with 2012.09 releases; you should recompile all C++ code using exceptions. The compatibility issue does not affect code produced by older Sourcery CodeBench Lite releases or third-party libraries built with other compilers.

IEEE 754 soft float NaN interpretation bug fixes.  The IEEE 754 soft-float emulation libraries have been corrected to consistently use the legacy NaN representations.

Exception handling bug fix.  A bug that sometimes caused an incorrect call to terminate during exception handling has been fixed.

N64 ABI fast software floating-point libraries.  A bug in GCC has been fixed that caused the fast software floating-point libraries to be disabled for the N64 ABI.

Temporary register assembler bug fix.  A bug has been fixed that caused $zero to be used as a temporary register for address calculation on some loads targeting that register.

Assembler bug fix for .stab directives.  An assembler bug has been fixed that caused incorrect code to be generated when .stab directives were used in microMIPS or MIPS16 mode.

Assembler bug fix for microMIPS symbol loads.  An assembler bug has been fixed that caused some microMIPS symbols to be loaded from an incorrect address.

N64 linker assertion failure fix.  A linker bug has been fixed that caused an assertion failure when linking N64 code using the special __ehdr_start symbol.

N64 FPU emulation bug fix.  A bug in the CS3 FPU emulation library has been fixed that made N64 hard-float code execute incorrectly on non-FPU processors.

GDB CP0 register access bug fix.  A bug in GDB has been fixed that made CP0 registers inaccessible.

Debug Sprite spurious error message bug fix.  A bug in the Sourcery CodeBench Debug Sprite has been fixed that caused a spurious Error initializing the target message upon startup in the attachment (-a) mode.

A.1.2. Changes in Sourcery CodeBench Lite 2013.05-8

Conditional expression bug fix.  A bug that caused an internal compiler error in some programs with conditional expressions has been fixed.

Missed optimization.  A bug that caused GCC to miss an opportunity to use short instructions when compiling with -mmicromips has been fixed.

Exception handling bug fix.  A bug that sometimes caused incorrect results when using C++ exception specifications has been fixed.

Incorrect optimization bug fix.  A compiler bug has been fixed that caused incorrect code to be generated for some comparisons unless optimization was suppressed with -fno-forward-propagate.

GCC version 4.7.3.  Sourcery CodeBench Lite for MIPS ELF is now based on GCC version 4.7.3. This update incorporates numerous bug fixes. For more information, see http://gcc.gnu.org/gcc-4.7/changes.html.

GCC option -meva GCC now passes the -meva command-line option to GAS.

IEEE 754-2008 features and multilibs added.  Support for some IEEE 754-2008 floating-point arithmetic standard features has been added to the toolchain for processors that implement them. This includes changes to the compiler, binutils, the dynamic linker and floating-point environment library functions. The changes enable support for the recommended encoding of NaN data introduced by the said revision of the standard as well as the use of the floating-point ABS.fmt and NEG.fmt instructions in a non-arithmetic manner. Multilibs built with the updated encoding of NaN data have been added. For information as to how to control these features, please refer to the compiler and assembler manuals.

Linker --gc-sections crash fix.  A bug that caused the linker to sometimes crash when using --gc-sections has been fixed.

Improved error message for incompatible object files.  The linker error message emitted when attempting to link objects with incompatible error handling formats now includes the object names.

Binutils update.  The binutils package has been updated to version 2.23.52.20130219 from the FSF trunk. This update includes numerous bug fixes.

Installer warnings fixed.  A bug that caused Gtk warnings relating to libappmenu.so when running the installer on 64-bit Ubuntu GNU/Linux hosts has been fixed.

microMIPS FPU emulation bug fix.  Support for the missing microMIPS RECIP.fmt and RSQRT.fmt instructions has been added to the CS3 FPU emulation library.

IEEE 754 integer conversion bug fix.  A bug in the CS3 FPU emulator has been fixed that caused integer conversion instructions to produce incorrect results. The bug triggered for the minimum valid, out-of-range, infinite and NaN inputs to the CEIL.L.fmt, CEIL.W.fmt, CVT.L.fmt, CVT.W.fmt, FLOOR.L.fmt, FLOOR.W.fmt, ROUND.L.fmt, ROUND.W.fmt, TRUNC.L.fmt, and TRUNC.W.fmt instructions run on processors without an FPU as well as processors whose FPU traps to the emulator for any of such inputs.

IEEE 754 signaling NaN interpretation bug fix.  A bug in the CS3 FPU emulator has been fixed that caused legacy signaling NaN data encoded with a zero payload to be interpreted as quiet NaN data. As a result IEEE 754 exception state was not set correctly for floating-point operations receiving such data as input. The bug affected hard-float code run on processors without an FPU as well as processors whose FPU traps to the emulator for signaling NaN input.

MIPS32r2 FPU emulation bug fix.  The CS3 FPU emulation library now correctly supports multiply-accumulate and reciprocal approximation instructions in MIPS32r2 code.

CS3 FPU emulator IEEE 754 features.  The CS3 FPU emulation library now supports some of the IEEE 754-2008 standard features recently added to the MIPS architecture. These are a new encoding of NaN data and a different treatment of ABS.fmt and NEG.fmt instructions as well as the associated new Floating Point Control and Status register state to switch between the IEEE 754-2008 and legacy mode.

Improved source line stepping.  GDB and gdbserver now implement range stepping, which improves the performance of single stepping over a source line by reducing the number of control messages from GDB.

GDB hang fix.  A bug that caused GDB to sometimes hang when setting a breakpoint has been fixed.

Sprite remote communication bug fix.  A bug in the Sourcery CodeBench Debug Sprite that caused it to exit with the error Remote communication error. Target disconnected.: Invalid argument. on some Microsoft Windows hosts has been fixed.

Debug Sprite with multiple connections.  The Sourcery CodeBench Debug Sprite now works correctly when using multiple connections (-m) with the Mentor Embedded Sourcery Probe. Previously, the Sprite exited with an error after the first connection.

Debug Sprite source line stepping improvement.  The Sourcery CodeBench Debug Sprite now supports range stepping when used with debug devices that implement this MDI feature.

A.1.3. Changes in Sourcery CodeBench Lite 2012.09-98

Fast software floating-point libraries.  A bug that caused the fast software floating-point libraries to be disabled has been fixed.

microMIPS branch generation fixed.  A bug in GCC has been fixed that caused it to generate out-of-range microMIPS branches, which resulted in a linker error relocation truncated to fit: R_MICROMIPS_PC16_S1.

Compact C++ language-specific data.  GCC now defaults to emitting a compact encoding of the C++ language-specific data for exception handling. For more information, refer to the documentation of the -mcompact-eh and -mno-compact-eh options in the GCC manual.

Pointer comparison bug fixed.  A bug in GCC that caused it to incorrectly optimize away a pointer comparison has been fixed.

Loop optimization bug fix.  A compiler bug that caused some forms of loop to be mis-optimized when using the -fpromote-loop-indices option has been fixed.

Wrong-code bug fix.  A bug in GCC's scheduler has been fixed that sometimes caused incorrect code to be generated.

Performance regression fixed.  A bug that introduced unnecessary instructions to zero-extend unsigned char or short values has been fixed.

Linker raw binary input crash fix.  A bug that caused the linker to crash when linking binary inputs (--format=binary) while using --gc-sections has been fixed.

Assembler bug fixes.  Assembler bugs have been fixed that caused assembly errors or incorrect code to be produced for the LUI instruction, microMIPS B16, BEQZ16, and BNEZ16 suffixed instruction mnemonics, as well as 32-bit microMIPS instructions placed in a 16-bit delay slot of a branch or a jump.

Install to empty directory failure fixed.  A bug that prevented installation of Sourcery CodeBench Lite into an existing empty directory has been fixed.

CS3 linking fix.  A bug has been fixed that caused relocation truncated to fit errors when linking the CS3 libraries against object files compiled with a -G option value less than 4.

ssize_t type definition bug fix.  The definition of the POSIX ssize_t data type has been corrected for 64-bit targets to match the width of the ISO C size_t type.

A.1.4. Changes in Sourcery CodeBench Lite 2012.09-42

GCC version 4.7.2.  Sourcery CodeBench Lite for MIPS ELF is now based on GCC version 4.7.2. For more information about changes from GCC version 4.6 that was included in previous releases, see http://gcc.gnu.org/gcc-4.7/changes.html.

Optimization bug fix.  A GCC bug has been fixed that caused incorrect code to be generated for builtin_unreachable when optimizing.

Linker crash bug fix.  A bug has been fixed that caused the linker to crash when using customized linker scripts without a .eh_frame_hdr output section description.

Assembler %hi and %lo operator bug fixes .  Several bugs have been fixed in the handling of %hi and %lo assembly operators applied to expressions involving forward symbol references. The bugs caused the assembler to fail with a relocation overflow error message or to produce incorrect code.

Linker script symbols.  The linker now supports a new HIDDEN keyword to define symbols with object scope. Refer to the linker manual for details.

microMIPS SWXC1 instruction encoding bug fix .  A bug in the encoding of the microMIPS SWXC1 instruction has been fixed. The bug caused LWXC1 to be produced by the assembler and listed by the disassembler instead.

Binutils version 2.23.  Sourcery CodeBench Lite for MIPS ELF is now based on binutils version 2.23.

EVA instruction assembler bug fix.  An assembler bug in branch delay slot optimization involving EVA instructions has been fixed.

Assembler internal error bug fix.  A bug has been fixed that caused the assembler to sometimes fail with a fixup not contained within frag error message. The bug was triggered by the branch delay slot optimization, not normally used for compiler-generated code.

N64 MDI semihosting bug fix.  A bug in MDI semihosting has been fixed that caused incorrect return values for the N64 ABI.

GDB update.  The included version of GDB has been updated to 7.4.50.20120716. This update adds numerous bug fixes and features. Refer to http://www.gnu.org/software/gdb/news for more information.

Non-stop support.  The Sourcery CodeBench Debug Sprite now supports non-stop debugging.

Updated system requirements.  The host operating system requirements for Sourcery CodeBench Lite have been updated. The minimum versions of GNU/Linux now supported are Red Hat Enterprise Linux 5, SuSE Enterprise Linux 10, Fedora Core 6, Ubuntu 8.04, and Debian 5, or later versions of these distributions running on 32-bit or 64-bit Intel or AMD CPUs.

A.1.5. Changes in Sourcery CodeBench Lite 2012.03-64

__attribute__((nomips16)) code generation bug fix .  A bug in GCC that caused incorrect code to be generated for functions with the __attribute__((nomips16)) attribute while compiling with -mips16 has been fixed.

C++ bug fix.  A bug that caused unpredictable program behavior in C++ programs has been fixed.

Invalid microMIPS relocation fixed.  A bug in branch code generation for microMIPS, reported by the linker as relocation truncated to fit: R_MICROMIPS_PC16_S1, has been fixed.

Improved size optimization for microMIPS.  The compiler now aligns microMIPS functions more efficiently when the -Os option is used.

Compiler crash fixed.  A GCC bug that occasionally caused an internal compiler error during register allocation has been fixed.

Register allocation bug fix.  A bug in the register allocator that caused incorrect code generation has been fixed.

Linker --gc-sections bug fix.  A linker bug that incorrectly caused undefined references to be diagnosed when the --gc-sections option is used has been fixed.

EVA support.  GAS now supports MIPS EVA instructions. You can specify the -meva option to GCC and GAS to indicate that EVA instructions are being used.

A.1.6. Changes in Sourcery CodeBench Lite 2012.03-41

Nondeterministic code generation bug fix.  A GCC bug has been fixed that caused nondeterministic code generation for some input files when optimizing.

GCC version 4.6.  Sourcery CodeBench Lite for MIPS ELF is now based on GCC version 4.6. For more information about changes from GCC version 4.5 that was included in previous releases, see http://gcc.gnu.org/gcc-4.6/changes.html.

Fix for internal compiler error.  A GCC bug has been fixed that caused an internal compiler error when using pointer casts in C++0x constexpr initialization expressions.

Compact C++ exception handling tables.  GCC now defaults to emitting a compact encoding of C++ exception handling tables, rather than using a DWARF-based scheme. For more information, refer to the documentation of the -mcompact-eh and -mno-compact-eh options in the GCC manual.

Fix for bit-field optimization bug.  A compiler bug that caused incorrect code to be generated for programs using bit-fields has been fixed.

Incorrect accesses to volatile memory.  The compiler no longer generates SWP, LWP, SWM or LWM instructions to access objects declared with the volatile type qualifier, as these instructions can cause multiple memory accesses of unspecified ordering.

GCC version 4.6.3.  Sourcery CodeBench Lite for MIPS ELF is now based on GCC version 4.6.3. For more information about issues that have been fixed since version 4.6.1, see http://gcc.gnu.org/gcc-4.6/changes.html.

GCC stack usage improvement.  GCC now generates better code for stack allocation in some cases when compiling with -fno-strict-aliasing.

Linker --gc-sections option bug fix.  A bug has been fixed that caused the linker to incorrectly remove the .debug_types section when using the --gc-sections option.

Installer failure during upgrade.  Some recent releases were affected by an installer bug on Windows hosts that caused installing a newer version of Sourcery CodeBench Lite into the same directory to fail with the error Sourcery CodeBench Lite for MIPS ELF upgrade failed. This bug has now been fixed, but the affected releases cannot be upgraded. As a workaround, uninstall the older release before installing the new version.

C++ debugging bug fix.  A GDB bug has been fixed that caused GDB to fail to find enum constants in base classes when debugging C++ code.

Fix for crash in GDB.  A memory corruption bug in GDB has been fixed that under very rare circumstances made it crash or exhibit other unpredictable behavior. On GNU/Linux hosts, this bug caused crashes with an error message similar to: *** glibc detected *** mips-sde-elf-gdb: free(): invalid next size (normal): 0x09466198 *** followed by a backtrace.

Fix debugger remote target interruption.  A bug in GDB's handling of requests to interrupt execution on a remote target has been fixed that caused it to stop the target but not emit a stopped MI record.

GDB internal error fix.  A bug has been fixed that caused GDB to produce messages of the form: warning: (Internal error: pc 0x1000a0 in read in psymtab, but not in symtab.) when taking the addresses of symbols from objects added with the add-symbol-file command.

A.1.7. Changes in Older Releases

For information about changes in older releases of Sourcery CodeBench Lite for MIPS ELF, please refer to the Getting Started guide packaged with those releases.