cmd/compile: apply optimization for readonly globals on wasm

Extend the optimization introduced in CL 141118 to the wasm architecture. And for reference, the rules trigger 212 times while building std and cmd $GOOS=js GOARCH=wasm gotip build std cmd $grep -E "Wasm.rules:44(1|2|3|4)" rulelog | wc -l 212 Updates golang#26498 Change-Id: I153684a2b98589ae812b42268da08b65679e09d1 Reviewed-on: https://go-review.googlesource.com/c/go/+/185477 Run-TryBot: Agniva De Sarker <agniva.quicksilver@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com> Reviewed-by: Richard Musiol <neelance@gmail.com>
t4n6a1ka · Sep 5, 2019 · f8da25d · f8da25d
1 parent e8fd7ee
commit f8da25d
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diff --git a/src/cmd/compile/internal/ssa/gen/Wasm.rules b/src/cmd/compile/internal/ssa/gen/Wasm.rules
@@ -417,3 +417,9 @@
 // folding offset into address
 (I64AddConst [off] (LoweredAddr {sym} [off2] base)) && isU32Bit(off+off2) ->
 	(LoweredAddr {sym} [off+off2] base)
+
+// transforming readonly globals into constants
+(I64Load [off] (LoweredAddr {sym} [off2] (SB)) _) && symIsRO(sym) && isU32Bit(off+off2) -> (I64Const [int64(read64(sym, off+off2, config.BigEndian))])
+(I64Load32U [off] (LoweredAddr {sym} [off2] (SB)) _) && symIsRO(sym) && isU32Bit(off+off2) -> (I64Const [int64(read32(sym, off+off2, config.BigEndian))])
+(I64Load16U [off] (LoweredAddr {sym} [off2] (SB)) _) && symIsRO(sym) && isU32Bit(off+off2) -> (I64Const [int64(read16(sym, off+off2, config.BigEndian))])
+(I64Load8U [off] (LoweredAddr {sym} [off2] (SB)) _) && symIsRO(sym) && isU32Bit(off+off2) -> (I64Const [int64(read8(sym, off+off2))])
diff --git a/src/cmd/compile/internal/ssa/rewriteWasm.go b/src/cmd/compile/internal/ssa/rewriteWasm.go
diff --git a/test/codegen/strings.go b/test/codegen/strings.go
@@ -29,20 +29,23 @@ func ConstantLoad() {
 	//   386:`MOVW\t\$12592, \(`,`MOVB\t\$50, 2\(`
 	//   arm:`MOVW\t\$48`,`MOVW\t\$49`,`MOVW\t\$50`
 	// arm64:`MOVD\t\$12592`,`MOVD\t\$50`
+	//  wasm:`I64Const\t\$12592`,`I64Store16\t\$0`,`I64Const\t\$50`,`I64Store8\t\$2`
 	bsink = []byte("012")
 
 	// 858927408 = 0x33323130
 	//     13620 = 0x3534
 	// amd64:`MOVL\t\$858927408`,`MOVW\t\$13620, 4\(`
 	//   386:`MOVL\t\$858927408`,`MOVW\t\$13620, 4\(`
 	// arm64:`MOVD\t\$858927408`,`MOVD\t\$13620`
+	//  wasm:`I64Const\t\$858927408`,`I64Store32\t\$0`,`I64Const\t\$13620`,`I64Store16\t\$4`
 	bsink = []byte("012345")
 
 	// 3978425819141910832 = 0x3736353433323130
 	// 7306073769690871863 = 0x6564636261393837
 	// amd64:`MOVQ\t\$3978425819141910832`,`MOVQ\t\$7306073769690871863`
 	//   386:`MOVL\t\$858927408, \(`,`DUFFCOPY`
 	// arm64:`MOVD\t\$3978425819141910832`,`MOVD\t\$1650538808`,`MOVD\t\$25699`,`MOVD\t\$101`
+	//  wasm:`I64Const\t\$3978425819141910832`,`I64Store\t\$0`,`I64Const\t\$7306073769690871863`,`I64Store\t\$7`
 	bsink = []byte("0123456789abcde")
 
 	// 56 = 0x38