From 4aeac68c92c5b79d098aaa7fba168d4c943541ba Mon Sep 17 00:00:00 2001 From: Josh Bleecher Snyder Date: Thu, 11 Apr 2019 12:18:10 -0700 Subject: runtime, cmd/compile: re-order PCDATA and FUNCDATA indices MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The pclntab encoding supports writing only some PCDATA and FUNCDATA values. However, the encoding is dense: The max index in use determines the space used. We should thus choose a numbering in which frequently used indices are smaller. This change re-orders the PCDATA and FUNCDATA indices using that principle, using a quick and dirty instrumentation to measure index frequency. It shrinks binaries by about 0.5%. Updates #6853 file before after Δ % go 14745044 14671316 -73728 -0.500% addr2line 4305128 4280552 -24576 -0.571% api 6095800 6058936 -36864 -0.605% asm 4930928 4906352 -24576 -0.498% buildid 2881520 2861040 -20480 -0.711% cgo 4896584 4867912 -28672 -0.586% compile 25868408 25770104 -98304 -0.380% cover 5319656 5286888 -32768 -0.616% dist 3654528 3634048 -20480 -0.560% doc 4719672 4691000 -28672 -0.607% fix 3418312 3393736 -24576 -0.719% link 6137952 6109280 -28672 -0.467% nm 4250536 4225960 -24576 -0.578% objdump 4665192 4636520 -28672 -0.615% pack 2297488 2285200 -12288 -0.535% pprof 14735332 14657508 -77824 -0.528% test2json 2834952 2818568 -16384 -0.578% trace 11679964 11618524 -61440 -0.526% vet 8452696 8403544 -49152 -0.581% Change-Id: I30665dce57ec7a52e7d3c6718560b3aa5b83dd0b Reviewed-on: https://go-review.googlesource.com/c/go/+/171760 Run-TryBot: Josh Bleecher Snyder TryBot-Result: Gobot Gobot Reviewed-by: Austin Clements --- src/runtime/funcdata.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'src/runtime/funcdata.h') diff --git a/src/runtime/funcdata.h b/src/runtime/funcdata.h index 1ee67c8683..d9a35c51a0 100644 --- a/src/runtime/funcdata.h +++ b/src/runtime/funcdata.h @@ -8,15 +8,15 @@ // // These must agree with symtab.go and ../cmd/internal/objabi/funcdata.go. -#define PCDATA_StackMapIndex 0 -#define PCDATA_InlTreeIndex 1 -#define PCDATA_RegMapIndex 2 +#define PCDATA_RegMapIndex 0 +#define PCDATA_StackMapIndex 1 +#define PCDATA_InlTreeIndex 2 #define FUNCDATA_ArgsPointerMaps 0 /* garbage collector blocks */ #define FUNCDATA_LocalsPointerMaps 1 -#define FUNCDATA_InlTree 2 -#define FUNCDATA_RegPointerMaps 3 -#define FUNCDATA_StackObjects 4 +#define FUNCDATA_RegPointerMaps 2 +#define FUNCDATA_StackObjects 3 +#define FUNCDATA_InlTree 4 // Pseudo-assembly statements. -- cgit v1.3