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authorBjörn Gustavsson <[email protected]>2016-04-07 10:06:44 +0200
committerBjörn Gustavsson <[email protected]>2016-04-08 10:28:42 +0200
commit3c0f98c1b0e74eb58a4e4e82a3ec89dc7ecdb579 (patch)
treec7b5544b9a7e506bc641302d265f6e44a468a660
parent0e1e90907ae76aae80f15316c2e43200a70d639b (diff)
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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().
-rw-r--r--erts/emulator/beam/beam_emu.c54
-rw-r--r--erts/emulator/beam/ops.tab9
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