Track register allocations #105

klauspost · 2020-01-02T13:26:12Z

To help debugging keep track of where registers are allocated.

After a bit back and forth I ended up with this, which shows sorted physical id and where the virtual register is allocated in the calling code:

failed to allocate registers. 56 virtual:                                                                                             
00: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:81 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64)                      
00:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:97 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)        
01: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:83 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64)                      
02: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:102 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64)                     
02:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:109 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
02:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:111 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
03: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:102 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64)                     
03:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:109 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
05: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:102 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64)                     
05:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:110 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
06: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:115 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64)                     
06:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:118 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
06:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:136 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
06:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:159 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
06:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:265 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
06:  - As8() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:116 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr8)         
07: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:134 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64)                     
07:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:135 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
07:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:136 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
07:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:137 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
08: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:160 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64)                     
08:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:163 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
09: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:176 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64)                     
09:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:183 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
10: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:176 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64)                     
10:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:180 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
10:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:183 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
11: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:176 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64)                     
11:  - As32() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:177 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32)       
11:  - As64() e:/gopath/src/github.com/klauspost/compress/s2/gen.go:193 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr64)       
[...]

When #100 is fixed this will allow easier tracking of what avo considers allocated.

If nothing else, it could also help debugging #100.

Using the package path is the most reasonable approach I could find to determine what to store.

To help debugging keep track of where registers are allocated. After a bit back and forth I ended up with this, which shows sorted physical id and where the virtual register is allocated in the calling code: ``` failed to allocate registers. 38 virtual: 00: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:81 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64) 00: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:81 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32) 01: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:83 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64) 02: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:102 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64) 02: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:102 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32) 03: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:102 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64) 03: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:102 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32) 05: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:102 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64) 05: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:102 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32) 06: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:115 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64) 06: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:115 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32) 06: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:115 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr8) 07: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:134 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64) 07: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:134 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32) 08: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:160 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64) 08: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:160 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32) 09: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:176 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64) 09: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:176 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32) 10: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:176 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64) 10: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:176 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32) 10: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:176 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr64) 11: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:186 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64) 11: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:186 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr16) 11: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:186 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32) 11: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:186 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr64) 11: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:186 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr8) 12: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:191 main.genEncodeBlockAsm() (type:reg.gpv, kind:gpr64) 12: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:191 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr64) 13: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:381 main.emitLiteral() (type:reg.gpv, kind:gpr64) 13: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:381 main.emitLiteral() (type:reg.virtual, kind:gpr16) 13: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:381 main.emitLiteral() (type:reg.virtual, kind:gpr32) 13: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:381 main.emitLiteral() (type:reg.virtual, kind:gpr8) 14: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:382 main.emitLiteral() (type:reg.gpv, kind:gpr64) 14: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:382 main.emitLiteral() (type:reg.virtual, kind:gpr32) 14: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:382 main.emitLiteral() (type:reg.virtual, kind:gpr8) 15: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:247 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr16) 15: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:247 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr32) 15: e:/gopath/src/github.com/klauspost/compress/s2/gen.go:247 main.genEncodeBlockAsm() (type:reg.virtual, kind:gpr8) ``` When mmcloughlin#100 is fixed this will allow easier tracking of what avo considers allocated. If nothing else, it could also help debugging mmcloughlin#100. Using the package path is the most reasonable approach I could find to determine what to store.

codecov-io · 2020-01-02T13:29:55Z

Codecov Report

Merging #105 into master will decrease coverage by 0.04%.
The diff coverage is 51.72%.

@@            Coverage Diff             @@
##           master     #105      +/-   ##
==========================================
- Coverage   76.18%   76.13%   -0.05%     
==========================================
  Files          52       53       +1     
  Lines       31325    31378      +53     
==========================================
+ Hits        23865    23891      +26     
- Misses       7355     7380      +25     
- Partials      105      107       +2

Flag	Coverage Δ
#integration	`6.45% <51.72%> (+0.07%)`	⬆️
#unittests	`74.09% <34.48%> (-0.08%)`	⬇️

Impacted Files	Coverage Δ
pass/alloc.go	`83.33% <0%> (-6.67%)`	⬇️
reg/x86.go	`70.21% <36.36%> (-29.79%)`	⬇️
reg/func.go	`78.57% <78.57%> (ø)`
reg/types.go	`89.47% <84.61%> (-1.12%)`	⬇️

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klauspost · 2020-01-02T15:05:21Z

reg/types.go

@@ -136,6 +148,8 @@ func (v virtual) as(s Spec) Register {
 		kind:  v.kind,
 		Width: Width(s.Size()),
 		mask:  s.Mask(),
+		// Non-breaking space for sorting.
+		allocAt: fmt.Sprintf("\u00A0- As%v() %s", s.String(), getFnNameFile(2)),


This breaks allocation, hinting that an == is used on this type somewhere.

I suspect the possible map[reg.Virtual][]reg.Physical is the problem here or with type Allocation map[Register]Physical

Separate AsX() in printing.

fe08d14

klauspost commented Jan 2, 2020

View reviewed changes

mmcloughlin force-pushed the master branch from 8263c8d to b76e849 Compare November 13, 2021 03:03

WojciechMula mentioned this pull request Apr 8, 2022

zstd: asm version of decodeSync klauspost/compress#545

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Track register allocations #105

Track register allocations #105

klauspost commented Jan 2, 2020 •

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klauspost Jan 2, 2020

klauspost Jan 2, 2020

Track register allocations #105

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klauspost commented Jan 2, 2020 • edited

codecov-io commented Jan 2, 2020 • edited

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klauspost commented Jan 2, 2020 •

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