[Wasm RyuJit] Codegen labels

[AndyAyersMS]

Create emitter labels for places Wasm will branch to, and display the instr group branch targets as comments when dumping out disassembly.

[AndyAyersMS]

@dotnet/jit-contrib PTAL

Provide annotations on the various Wasm branches to indicate their target (since they just show the depth in the control flow stack). See the br_if below.

We might be able to get by with more "lightweight" labels since we don't need to have the emitter do any GC tracking.

; Method Program:<<Main>$>g__Foo|0_0(int,int):int (FullOpts)
G_M10749_IG01:  ;; offset=0x0000
						;; size=0 bbWeight=1 PerfScore 0.00

G_M10749_IG02:  ;; offset=0x0000
       02                          |       block
       02                          |       block
       28 00 04                    |       i32.load 1 4
       41 00                       |       i32.const 0
       4C                          |       i32.le_s
       0D 00                       |       br_if 0 ;; G_M10749_IG04
						;; size=10 bbWeight=1 PerfScore 6.00

G_M10749_IG03:  ;; offset=0x000A
       28 00 00                    |       i32.load 1 0
       41 00                       |       i32.const 0
       4A                          |       i32.gt_s
       0D 01                       |       br_if 1 ;; G_M10749_IG07
       0B                          |       end
						;; size=9 bbWeight=0.50 PerfScore 2.50

G_M10749_IG04:  ;; offset=0x0013
       28 00 04                    |       i32.load 1 4
       28 00 00                    |       i32.load 1 0
       6A                          |       i32.add
						;; size=7 bbWeight=0.50 PerfScore 1.50

G_M10749_IG05:  ;; offset=0x001A
       0F                          |       return
						;; size=1 bbWeight=0.50 PerfScore 0.50

G_M10749_IG06:  ;; offset=0x001B
       0B                          |       end
						;; size=1 bbWeight=0.50 PerfScore 0.50

G_M10749_IG07:  ;; offset=0x001C
       41 03                       |       i32.const 3
						;; size=2 bbWeight=0.50 PerfScore 0.50

G_M10749_IG08:  ;; offset=0x001E
       0F                          |       return
						;; size=1 bbWeight=0.50 PerfScore 0.50
; Total bytes of code: 31

[Copilot]

Pull request overview

This PR implements codegen label support for WebAssembly RyuJIT. The changes enable the emitter to create and track labels for branch targets, and display branch target information as comments when dumping disassembly.

Key Changes

• Added emitIns_J function to emit jump instructions with target block information
• Introduced _idJump bitfield flag to instrDesc for tracking jump instructions
• Implemented IF_LABEL instruction format output (previously NYI_WASM)
• Enhanced disassembly display to show branch target labels as comments

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
src/coreclr/jit/emitwasm.h	Added declaration for new emitIns_J function
src/coreclr/jit/emitwasm.cpp	Implemented emitIns_J, removed NYI_WASM for IF_LABEL, added jump target display logic, fixed brace formatting
src/coreclr/jit/emit.h	Added _idJump bitfield and helper methods, updated bit count comments
src/coreclr/jit/codegenwasm.cpp	Added label marking for loops and block ends, updated calls to use emitIns_J, fixed comment typo

[JulieLeeMSFT]

LGTM.

[AndyAyersMS]

spmi failures

Running: git fetch --depth=500 origin main
fatal: unable to access 'https://github.com/dotnet/runtime/': Connection timed out after 300046 milliseconds