IAR Information Center for ARM

• Important information
• New features
• Known problems
• Program corrections
• User guide corrections
• Miscellaneous
• Release history

Important information

• Changed C-STAT behaviour in version 7.60
  

  • The analysis engine has been improved to increase the analysis precision for both existing and added coding rules. This can have the effect that the number of issued messages for a file or project can differ compared to previous versions of C-STAT, even if the enabled checks are exactly the same.

  • C-STAT settings in an old IAR Embedded Workbench IDE or Eclipse project will be updated. Some checks will be renamed (they retain their enabled or disabled settings), some checks are removed, and many new checks are added (see above).

  • Importing settings for C-STAT checks from a file will use the same logic as used when updating the project settings, if the settings file is created with an old version of C-STAT.

• If you have implemented the time() function, you must rename it into __time32(). For more information see the Development guide.

• The --guard_calls command line option is introduced. Note, --guard_calls must always be used in applications written in EC++/C++ that need thread-safe library function calls. For more information see the Development guide.

  The --no_guard_calls command line option is removed.

  The --aeabi command line option has modified behavior: Guard calls are not used by default.
  Migration instructions from IAR C/C++ Compiler for ARM 5.x and 6.10.1 to IAR C/C++ Compiler for ARM 6.10.2:
  --aeabi (without --no_guard_calls) shall be replaced with --aeabi --guard_calls
--aeabi --no_guard_calls shall be replaced with --aeabi
  

• A special note on CMSIS integration:
  

  If your application source code include CMSIS header files explicitly, then you should not check the Use CMSIS check-box Project>Options...>General Options>Library Configuration>Use CMSIS. Some of the Cortex-M application examples includes CMSIS source files explicitly, do not check the said check-box in these projects.
  
  However, due to the evolution of the IAR C/C++ Compiler for ARM, older versions of CMSIS are incompatible with the current version of the compiler. One simple example of how to solve this issue is:
  a) Press F4 to bring up the erroneous source (header) file in the editor - in most cases named core_cm3.h.
  b) Right-click on the window tab of that editor window, choose File Properties....
  c) Add (or remove) any character to the file name - so the compiler won't find it any more.
  d) Modify project options: Check Project>Options...>General Options>Library Configuration>Use CMSIS.
  Steps a) to c) might need to be done for more than one file. Normally, the names of these files are core_cm0.h, core_cm3.h, core_cm4.h, core_cmFunc.h and core_cmInstr.h.
  
  For more information about CMSIS integration in the IAR Embedded Workbench for ARM, see the Development guide.

• Not using interwork when compiling for ARM architecture v4 is deprecated
  

  For now, this mode is supported like in earlier versions of the product, but new features, like C-RUN, will not have support for this mode.

• Deprecated features

  • --use_old_syntax

    The compiler option --use_old_syntax will be removed in future versions of the IAR C/C++ Compiler for ARM.

  • --interwork

    Future versions of the IAR C/C++ Compiler for ARM will assume --interwork when generating code for the ARMv4T architecture. There will be no option to generate non-interworking code for ARMv4T.

New features

• None.

Known Problems

• Assembler file listing containing initializers for a data object that has a type that uses __packed or #pragma pack, is incorrect.
  [EW23889]

• MISRA C:2004 rule 9.1 will not find all used uninitialized local variables.
  [EW24720]

• The overload resolution algorithm doesn't take into account template user conversion for argument deduction when finding out what built-in operator that is the best fit.
  [EW24930]

• Passing a parameter of type va_list to a C++ function, where the caller is defined in one object file and the callee in another, will result in a linker error if one of the two objects is built with EWARM 7.20 (or newer) and the other is built with EWARM 7.10 (or older).
  [EW25660]

• Sometimes vget_lane_xxx or vgetq_lane_xxx can generate internal error.
  [EW26156]

Program Corrections

• Initializing an array of aggregates, parts of which are plain-old-data, with a braced initializer list with fewer entries than the number of elements in the array could cause the compiler to terminate with an internal error (assertion failed in decl_inits.c).
  [EW26298]

• A function containing two (or more) identical tests that occur in or as arithmetic expressions can in some cases be optimized incorrectly on optimization level High.
  [EW26325]

• On optimization level Medium or High accesses to a const __weak structure or array variables can be optimized incorrectly.
  [EW26346]

• Missing an ENDM when recording a macro causes an internal error when using the macro.
  [EW26360]

• The template project for rebuilding DLIB libraries contained a file difftime_i.c, which requires a header file that is not included in the distribution. The file difftime_i.c is no longer part of the project.
  [EW26372]

• Some complex array address expressions can trigger an internal error.
  [EW26388]

• Warning Pe111 (statement is unreachable) is incorrectly not issued for code after a call to a noreturn function.
  [EW26389]

• In rare cases the intra-crossjump optimization can remove code that is still used.
  [EW26429]

• Variables with static or thread storage duration can be optimized incorrectly on optimization level Medium or High, if they are incremented or decremented with a constant amount and there is only a single use in the rest of the function.
  [EW26446]

• Functions where the address of an array with automatic storage duration is passed to an inline assembler statement can be optimized incorrectly on optimization level High.
  [EW26448]

User guide corrections

• None.

Miscellaneous

• Available workarounds for device erratas:
  
  

  • ARM Cortex-M3 errata 463764
    Core may freeze for SLEEPONEXIT single instruction ISR. More information is available on infocenter.arm.com.
    Workaround generated for functions with attribute __irq with iccarm --enable_hardware_workaround=arm463764. Supported from EWARM 5.41.

  • ARM Cortex-M3 errata 602117
    LDRD with base in list may result in incorrect base register when interrupted or faulted. From EWARM 5.20.3 the compiler/library avoids the LDRD instruction with the base register in list.

  • ARM Cortex-M3 errata 752419
    ARM Cortex-M4 errata 752770
    Interrupted loads to SP can cause erroneous behaviour. From EWARM 6.21 the compiler/library does not generate LDR SP instructions with writeback to Rn. Otherwise we allow the extra reads since the stack resides in RAM where multiple reads are acceptable.

  • ARM Cortex-M7 errata 833872
    Flag setting instructions inside IT block might cause incorrect execution of subsequent instructions. From EWARM 7.40 the compiler will the skip the IT transformation on this particular code pattern.

  • ARM Cortex-M3 errata 838469
    ARM Cortex-M4 errata 838869
    Store immediate overlapping exception return operation might vector to incorrect interrupt. The user should follow the guidelines in the errata and implement the workaround proposed by ARM by using __DSB(void) in applicable cases.

  • Functional problem Core.1 in NXP device LPC2478: Incorrect update of the Abort Link register in Thumb state.
    Workaround generated with iccarm --enable_hardware_workaround=NXP_Core.1

  • Functional problem in Stellaris devices: Non-word-aligned write to SRAM can cause incorrect value to be loaded. More information is available on the Stellaris web site at www.ti.com/stellaris.
    Workaround generated with iccarm --enable_hardware_workaround=LM3S_NWA_SRAM_Write

  • Functional problem in Freescale Semiconductors MC9328MX1 (i.MX1), masks 0L44N, 1L44N, and 2L44N:
    The LDM instruction will in some cases not load the second register correctly. Workaround generated with iccarm --enable_hardware_workaround=920t-ldm2
    NOTE: The libraries in the current EWARM version are not built with this workaround. Use EWARM 6.50.6 and linker option --enable_hardware_workaround=920t-ldm2 to use libraries built with this hardware workaround.

• The implementation of va_args functions have changed in IAR Embedded Workbench for ARM 7.20.1. It is no longer possible to compile the output of the pre-processor from an earlier version of the compiler. The original source code must be pre-processed again, using IAR Embedded Workbench for ARM 7.20.1.

Release history

See release history.