OTP-9604 The profiling test tool has been rewritten. Håkan Mattsson OTP-9679 Merge branch 'bmk/megaco/r15_integration'
* bjorn/fun-improvements/OTP-9667: sys_pre_expand: Remove incorrect comment compiler: Eliminate use of deprecated erlang:hash/2 beam_asm: Fix broken NewIndex in fun entries beam_asm: Strenghten the calculation of Uniq for funs
* bjorn/external-funs/OTP-9643: EEP-23: Allow variables in fun M:F/A Reference manual: Improve the documentation for external funs Test calling a parameterized module within a fun beam_loader: Support external funs in the literal pool
sys_pre_expand does not keep track of used or new variables (and have not done since about the time Core Erlang was introduced).
Now that beam_asm computes the Index and Uniq values for funs, there is no need to compute those values in the sys_pre_expand and v3_kernel modules, thus eliminating the calls to the deprecated erlang:hash/2 function. It would be tempting to stop generating the name for the fun in sys_pre_expand so that we did not have to add the Info field to a tuple. But: * The debugger depends on the name being there. (Simple solution: Let the debugger generate the name itself.) * When a fun has been inlined into another function, the fun name in 'id' annotation will be used to notice the inlining and change the final clause of the top-level case from generating a 'function_clause' exception to a case_clause exception. (Possible workaround: Have the inliner set an inlined attribute on functions that have been inlined, or have the inliner rewrite 'function_clause' exceptions itself.)
The calculation of the NewIndex field in fun entries is broken: the sys_pre_expand and v3_kernel modules keep separate index counters starting at zero; thus there is no guarantee that each fun within a module will have its own unique NewIndex. We don't really need the NewIndex any more (see below), but since we do need the NewUniq field, we should fix NewIndex for cleanliness sake. The simplest way is to assign NewIndex as late as possible, namely in beam_asm, and to set it to the same value as Index. Historical Note: Why NewIndex Was Introduced There was once an idea that the debugger should be able to interpret only a single function in a module (for speed). To make sure that interpreted funs could be called from BEAM code and vice versa, the fun identification must be visible in the abstract code. Therefore a NewIndex field was introduced in each fun in the abstract code. However, it turned out that interpreting single functions does not play well with aggressive code optimization. For example, in this code: f() -> X = 1, fun() -> X+2 end. the variable X will seem to be free in the fun, but an aggressive optimizer will replace X with 1 in the fun; thus the fun will no longer have any free variables. Therefore, the debugger will always interpret entire modules.
Funs are identified by a triple, <Module,Uniq,Index>, where Module is the module name, Uniq is a 27 bit hash value of some intermediate representation of the code for the fun, and index is a small integer. When a fun is loaded, the triple for the fun will be compared to previously loaded funs. If all elements in the triple in the newly loaded fun are the same, the newly loaded fun will replace the previous fun. The idea is that if Uniq are the same, the code for the fun is also the same. The problem is that Uniq is only based on the intermediate representation of the fun itself. If the fun calls local functions in the same module, Uniq may remain the same even if the behavior of the fun has been changed. See http://erlang.org/pipermail/erlang-bugs/2007-June/000368.htlm for an example. As a long-term plan to fix this problem, the NewIndex and NewUniq fields was added to each fun in the R8 release (where NewUniq is the MD5 of the BEAM code for the module). Unfortunately, it turns out that the compiler does not assign unique value to NewIndex (if it isn't tested, it doesn't work), so we cannot use the <Module,NewUniq,NewIndex> triple as identification. It would be possible to use <Module,NewUniq,Index>, but that seems ugly. Therefore, fix the problem by making Uniq more unique by taking 27 bits from the MD5 for the BEAM code. That only requires a change to the compiler. Also update a test case for cover, which now fails because of the stronger Uniq calculation. (The comment in test case about why the Pid2 process survived is not correct.)
Currently, the external fun syntax "fun M:F/A" only supports literals. That is, "fun lists:reverse/1" is allowed but not "fun M:F/A". In many real-life situations, some or all of M, F, A are not known until run-time, and one is forced to either use the undocumented erlang:make_fun/3 BIF or to use a "tuple fun" (which is deprecated). EEP-23 suggests that the parser (erl_parse) should immediately transform "fun M:F/A" to "erlang:make_fun(M, F, A)". We have not followed that approach in this implementation, because we want the abstract code to mirror the source code as closely as possible, and we also consider erlang:make_fun/3 to be an implementation detail that we might want to remove in the future. Instead, we will change the abstract format for "fun M:F/A" (in a way that is not backwards compatible), and while we are at it, we will move the translation from "fun M:F/A" to "erlang:make_fun(M, F, A)" from sys_pre_expand down to the v3_core pass. We will also update the debugger and xref to use the new format. We did consider making the abstract format backward compatible if no variables were used in the fun, but decided against it. Keeping it backward compatible would mean that there would be different abstract formats for the no-variable and variable case, and tools would have to handle both formats, probably forever. Reference: http://www.erlang.org/eeps/eep-0023.html
Merge branch 'ssl-cbc-fix' * ssl-cbc-fix: fix handling of block_decipher/5 failure
OTP-9604 Merge branch 'bmk/megaco/20111003/improving_mstone1/OTP-9604' into bmk/megaco/r15_integration Conflicts: lib/megaco/doc/src/notes.xml
Håkan Mattsson. OTP-9679 Merge branch 'bmk/megaco/improving_profiling_tool/OTP-9679' into bmk/megaco/r15_integration
It is tempting to transform code such as: fun(X) -> M:foo(X) end to: fun M:foo/1 Unfortunately, that transformation is not safe if M happens to be a parameterized module. Add a test case so that we don't attempt to do such an optimization in the future.
A future release of the compiler might want to treat external funs as literals. Make sure that the loader can cope with an export entry being created from both an entry in the literal pool and from the export table (i.e. if an external fun refers to an exported function in the same module).
Make it clear for the user what has happened and how to fix it when an attempt is made to load a BEAM file containing new instructions that the current run-time system cannot handle. Suggested-by: Thomas Lindgren
* lukas/kernel/tc_fixes: Kill nodes inbetween tests
* lukas/erts/large_float_cmp/OTP-9497: Update documentation after changes in integer and float comparison Do small optimisation on platforms with 32 bit Eterm Add tests for equality checking Optimize comparison of huge floats and smaller bignums Add tests for comparing large floats and small bignums Cleanup double_to_bignum conversion code Update size of tmp cmp bignum buffer Expand tests for float and number comparison Update heauristic to work on halfword Add heauristics bignum vs float checks Optimise bugnum and small comparison Add float vs integer comparison tests Update integer and floating point number comparisons
* lukas/megaco/remove_driver_warning/OTP-9672: Remove the warning that driver option is replaced by nif
* siri/observer/ttb-test-cleanup-slave-nodes/OTP-9644: Adjust ttb_SUITE to work better on windows Cleanup after testcases in ttb_SUITE
* siri/observer/close-ip-to-file-trace-port/OTP-9665: Close ip_to_file trace port in ttb:stop
and some added comments
These dependency files was once used when building the documentation, but are no longer needed.
Some applications still have support for an ancient documentation build system. Eliminate the DOCSUPPORT define in otp.mk.in and the not taken arm of the ifdefs in the Makefiles.
* bjorn/eliminate-regexp-usage: erl_tidy: Eliminate two references to 'regexp' in the documentation erts/z_SUITE: Eliminate use of deprecated regexp module erts/nt_SUITE: Eliminate use of deprecated regexp module erl_html_tools: Eliminate mention of deprecated regexp module erl_interface tests: Eliminate use of deprecated regexp module tools test suite: Eliminate compilation warnings for the eed module tools test suite: Eliminate use of deprecated regexp module xmerl test suite: Eliminate use of deprecated regexp module appmon: Eliminate use of deprecated regexp module tv: Eliminate use of deprecated regexp module gs: Eliminate use of deprecated regexp module inviso: Eliminate use of deprecated regexp module