[dev.ssa] cmd/compile: use string contents instead of offset from string header
This generates more efficient code.
Before:
0x003a 00058 (rr.go:7) LEAQ go.string.hdr."="(SB), BX
0x0041 00065 (rr.go:7) LEAQ 16(BX), BP
0x0045 00069 (rr.go:7) MOVQ BP, 16(SP)
After:
0x003a 00058 (rr.go:7) LEAQ go.string."="(SB), BX
0x0041 00065 (rr.go:7) MOVQ BX, 16(SP)
It also matches the existing backend
and is more robust to other changes,
such as CL 11698, which I believe broke
the current code.
This CL fixes the encoding/base64 tests, as run with:
GOGC=off GOSSAPKG=base64 go test -a encoding/base64
Change-Id: I3c475bed1dd3335cc14e13309e11d23f0ed32c17
Reviewed-on: https://go-review.googlesource.com/12654
Reviewed-by: Keith Randall <khr@golang.org>
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 0ea5aa4..e7772a9 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -1922,12 +1922,12 @@
mustImplement bool
}
-// StringSym returns a symbol (a *Sym wrapped in an interface) which
-// is a global string constant containing s.
-func (*ssaExport) StringSym(s string) interface{} {
+// StringData returns a symbol (a *Sym wrapped in an interface) which
+// is the data component of a global string constant containing s.
+func (*ssaExport) StringData(s string) interface{} {
// TODO: is idealstring correct? It might not matter...
- hdr, _ := stringsym(s)
- return &ssa.ExternSymbol{Typ: idealstring, Sym: hdr}
+ _, data := stringsym(s)
+ return &ssa.ExternSymbol{Typ: idealstring, Sym: data}
}
// Log logs a message from the compiler.
