| Age | Commit message (Collapse) | Author | |
|---|---|---|---|
| 2018-08-24 | Introduce a new SSA-based intermediate format | Björn Gustavsson | |
| v3_codegen is replaced by three new passes: * beam_kernel_to_ssa which translates the Kernel Erlang format to a new SSA-based intermediate format. * beam_ssa_pre_codegen which prepares the SSA-based format for code generation, including register allocation. Registers are allocated using the linear scan algorithm. * beam_ssa_codegen which generates BEAM assembly code from the SSA-based format. It easier and more effective to optimize the SSA-based format before X and Y registers have been assigned. The current optimization passes constantly have to make sure no "holes" in the X register assignments are created (that is, that no X register becomes undefined that an allocation instruction depends on). This commit also introduces the following optimizations: * Replacing of tuple matching of records with the is_tagged_tuple instruction. (Replacing beam_record.) * Sinking of get_tuple_element instructions to just before the first use of the extracted values. As well as potentially avoiding extracting tuple elements when they are not actually used on all executions paths, this optimization could also reduce the number values that will need to be stored in Y registers. (Similar to beam_reorder, but more effective.) * Live optimizations, removing the definition of a variable that is not subsequently used (provided that the operation has no side effects), as well strength reduction of binary matching by replacing the extraction of value from a binary with a skip instruction. (Used to be done by beam_block, beam_utils, and v3_codegen.) * Removal of redundant bs_restore2 instructions. (Formerly done by beam_bs.) * Type-based optimizations across branches. More effective than the old beam_type pass that only did type-based optimizations in basic blocks. * Optimization of floating point instructions. (Formerly done by beam_type.) * Optimization of receive statements to introduce recv_mark and recv_set instructions. More effective with far fewer restrictions on what instructions are allowed between creating the reference and entering the receive statement. * Common subexpression elimination. (Formerly done by beam_block.) | |||
| 2018-06-18 | Update copyright year | Henrik Nord | |
| 2017-12-07 | v3_codegen: Simplify #k_guard_break{} | Björn Gustavsson | |
| It turns out that we don't need to keep track of locked variables, because the locked variables are always the same variables that will be alive after a #k_guard_break{}. | |||
| 2017-10-27 | Eliminate the v3_life pass | Björn Gustavsson | |
| The v3_life pass does not do enough to be worth being its own pass. Essentially it does two things: * Calculates life-time information starting from the annotations that v3_kernel provides. That part can be moved into v3_codegen. * Rewrites the Kernel Erlang records to similar plain tuples (for example, #k_cons{hd=Hd,tl=Tl} is rewritten to {cons,Hd,Tl}). That rewriting is not needed and can be eliminated. | |||
| 2016-11-18 | v3_kernel: Generate optimized code for guards | Björn Gustavsson | |
| The compiler produces poor code for complex guard expressions with andalso/orelse. Here is an example from the filename module: -define(IS_DRIVELETTER(Letter),(((Letter >= $A) andalso (Letter =< $Z)) orelse ((Letter >= $a) andalso (Letter =< $z)))). skip_prefix(Name, false) -> Name; skip_prefix([L, DrvSep|Name], DrvSep) when ?IS_DRIVELETTER(L) -> Name; skip_prefix(Name, _) -> Name. beam_bool fails to simplify the code for the guard, leaving several 'bif' instructions: {function, skip_prefix, 2, 49}. {label,48}. {line,[{location,"filename.erl",187}]}. {func_info,{atom,filename},{atom,skip_prefix},2}. {label,49}. {test,is_ne_exact,{f,52},[{x,1},{atom,false}]}. {test,is_nonempty_list,{f,52},[{x,0}]}. {get_list,{x,0},{x,2},{x,3}}. {test,is_nonempty_list,{f,52},[{x,3}]}. {get_list,{x,3},{x,4},{x,5}}. {bif,'=:=',{f,52},[{x,1},{x,4}],{x,6}}. {test,is_ge,{f,50},[{x,2},{integer,65}]}. {bif,'=<',{f,52},[{x,2},{integer,90}],{x,7}}. {test,is_eq_exact,{f,51},[{x,7},{atom,false}]}. {test,is_ge,{f,50},[{x,2},{integer,97}]}. {bif,'=<',{f,52},[{x,2},{integer,122}],{x,7}}. {jump,{f,51}}. {label,50}. {move,{atom,false},{x,7}}. {label,51}. {bif,'=:=',{f,52},[{x,7},{atom,true}],{x,7}}. {test,is_eq_exact,{f,52},[{x,6},{atom,true}]}. {test,is_eq_exact,{f,52},[{x,7},{atom,true}]}. {move,{x,5},{x,0}}. return. {label,52}. return. We can add optimizations of guard tests to v3_kernel to achive a better result: {function, skip_prefix, 2, 49}. {label,48}. {line,[{location,"filename.erl",187}]}. {func_info,{atom,filename},{atom,skip_prefix},2}. {label,49}. {test,is_ne_exact,{f,51},[{x,1},{atom,false}]}. {test,is_nonempty_list,{f,51},[{x,0}]}. {get_list,{x,0},{x,2},{x,3}}. {test,is_nonempty_list,{f,51},[{x,3}]}. {get_list,{x,3},{x,4},{x,5}}. {test,is_eq_exact,{f,51},[{x,1},{x,4}]}. {test,is_ge,{f,51},[{x,2},{integer,65}]}. {test,is_lt,{f,50},[{integer,90},{x,2}]}. {test,is_ge,{f,51},[{x,2},{integer,97}]}. {test,is_ge,{f,51},[{integer,122},{x,2}]}. {label,50}. {move,{x,5},{x,0}}. return. {label,51}. return. Looking at the STDLIB application, there were 112 lines of BIF calls in guards that beam_bool failed to convert to test instructions. This commit eliminates all those BIF calls. Here is how I counted the instructions: $ PATH=$ERL_TOP/bin:$PATH erlc -I ../include -I ../../kernel/include -S *.erl $ grep "bif,'[=<>]" *.S | grep -v f,0 dets.S: {bif,'=:=',{f,547},[{x,4},{atom,read_write}],{x,4}}. dets.S: {bif,'=:=',{f,547},[{x,5},{atom,saved}],{x,5}}. dets.S: {bif,'=:=',{f,589},[{x,5},{atom,read}],{x,5}}. . . . $ grep "bif,'[=<>]" *.S | grep -v f,0 | wc 112 224 6765 $ | |||
| 2016-09-21 | v3_life: Eliminate special handling of guards | Björn Gustavsson | |
| Remove the special handling #k_try{} in guards in v3_life. If we introduce a new #k_protected{} record in v3_kernel, v3_life no longer needs to know whether it is processing guards or bodies. | |||
| 2016-03-15 | update copyright-year | Henrik Nord | |
| 2015-06-18 | Change license text to APLv2 | Bruce Yinhe | |
| 2014-06-24 | compiler: Fix v3_kernel Maps pretty printing | Björn-Egil Dahlberg | |
| 2014-02-07 | compiler: Fix codegen multiple updates for Maps | Björn-Egil Dahlberg | |
| This fixes an error on multiple updates optimization for map pairs. The error was introduced with moving to term order in Maps. This also fixes an error where register life time was lost for values and could result in erroneuos values being emitted in for map pairs. Simplified v3_codegen by moving multiple update optimizations to v3_kernel. | |||
| 2014-01-29 | compiler: Squash #k_map_pair_*{} to #k_map_pair{} | Björn-Egil Dahlberg | |
| Simplify compiler internals for kernel passes. | |||
| 2014-01-28 | Pass the map pair operators through to the v3_codegen pass | Björn Gustavsson | |
| 2014-01-28 | Implement support for maps in the compiler | Björn Gustavsson | |
| To make it possible to build the entire OTP system, also define dummys for the instructions in ops.tab. | |||
| 2012-03-30 | Update copyright years | Björn-Egil Dahlberg | |
| 2012-01-11 | v3_kernel.hrl: Remove unused record #k_string{} | Björn Gustavsson | |
| 2009-11-20 | The R13B03 release.OTP_R13B03 | Erlang/OTP | |
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index : otp.git | |
| Mirror of Erlang/OTP repository. | OTP Team |
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