From 3c0f98c1b0e74eb58a4e4e82a3ec89dc7ecdb579 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Thu, 7 Apr 2016 10:06:44 +0200 Subject: Simplify the raise instruction to reduce code size The raise/2 instruction is almost always used like this: raise x(2) x(1) Therefore, we can translate it to an internal i_raise/0 instruction that uses x(2) x(1) as its implicit operands. We will also remove the backward compatibility with R10-0. It is unlikely that anyone still is using BEAM files compiled with the R10-0 compiler, especially since most of those modules cannot be loaded. The loader will refuse to load any module that uses the old non-GCIng arithmetic instructions or the non-GCing versions of length/1 or size/1. Doing these changes will reduce both the size of the loaded BEAM code and size of the code in process_main(). --- erts/emulator/beam/beam_emu.c | 54 ++++++++++--------------------------------- erts/emulator/beam/ops.tab | 9 +++++++- 2 files changed, 20 insertions(+), 43 deletions(-) diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c index 09a41f2b56..d648a2f23c 100644 --- a/erts/emulator/beam/beam_emu.c +++ b/erts/emulator/beam/beam_emu.c @@ -3360,48 +3360,18 @@ do { \ goto do_schedule; } - OpCase(raise_ss): { - /* This was not done very well in R10-0; then, we passed the tag in - the first argument and hoped that the existing c_p->ftrace was - still correct. But the ftrace-object already includes the tag - (or rather, the freason). Now, we pass the original ftrace in - the first argument. We also handle atom tags in the first - argument for backwards compatibility. - */ - Eterm raise_val1; - Eterm raise_val2; - GetArg2(0, raise_val1, raise_val2); - c_p->fvalue = raise_val2; - if (c_p->freason == EXC_NULL) { - /* a safety check for the R10-0 case; should not happen */ - c_p->ftrace = NIL; - c_p->freason = EXC_ERROR; - } - /* for R10-0 code, keep existing c_p->ftrace and hope it's correct */ - switch (raise_val1) { - case am_throw: - c_p->freason = EXC_THROWN & ~EXF_SAVETRACE; - break; - case am_error: - c_p->freason = EXC_ERROR & ~EXF_SAVETRACE; - break; - case am_exit: - c_p->freason = EXC_EXIT & ~EXF_SAVETRACE; - break; - default: - {/* R10-1 and later - XXX note: should do sanity check on given trace if it can be - passed from a user! Currently only expecting generated calls. - */ - struct StackTrace *s; - c_p->ftrace = raise_val1; - s = get_trace_from_exc(raise_val1); - if (s == NULL) { - c_p->freason = EXC_ERROR; - } else { - c_p->freason = PRIMARY_EXCEPTION(s->freason); - } - } + OpCase(i_raise): { + Eterm raise_trace = x(2); + Eterm raise_value = x(1); + struct StackTrace *s; + + c_p->fvalue = raise_value; + c_p->ftrace = raise_trace; + s = get_trace_from_exc(raise_trace); + if (s == NULL) { + c_p->freason = EXC_ERROR; + } else { + c_p->freason = PRIMARY_EXCEPTION(s->freason); } goto find_func_info; } diff --git a/erts/emulator/beam/ops.tab b/erts/emulator/beam/ops.tab index 15f27835a8..96a3a72bb5 100644 --- a/erts/emulator/beam/ops.tab +++ b/erts/emulator/beam/ops.tab @@ -251,7 +251,14 @@ case_end x badmatch x if_end -raise s s + +# Operands for raise/2 are almost always in x(2) and x(1). +# Optimize for that case. +raise x==2 x==1 => i_raise +raise Trace=y Value=y => move Trace x=2 | move Value x=1 | i_raise +raise Trace Value => move Trace x=3 | move Value x=1 | move x=3 x=2 | i_raise + +i_raise # Internal now, but could be useful to make known to the compiler. badarg j -- cgit v1.2.3