cmd/compile: remove Symbol wrappers from Aux fields
We used to have {Arg,Auto,Extern}Symbol structs with which we wrapped
a *gc.Node or *obj.LSym before storing them in the Aux field
of an ssa.Value. This let the SSA part of the compiler distinguish
between autos and args, for example. We no longer need the wrappers
as we can query the underlying objects directly.
There was also some sloppy usage, where VarDef had a *gc.Node
directly in its Aux field, whereas the use of that variable had
that *gc.Node wrapped in an AutoSymbol. Thus the Aux fields didn't
match (using ==) when they probably should.
This sloppy usage cleanup is the only thing in the CL that changes the
generated code - we can get rid of some more unused auto variables if
the matching happens reliably.
Removing this wrapper also lets us get rid of the varsyms cache
(which was used to prevent wrapping the same *gc.Node twice).
Change-Id: I0dedf8f82f84bfee413d310342b777316bd1d478
Reviewed-on: https://go-review.googlesource.com/64452
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
diff --git a/src/cmd/compile/internal/ssa/gen/genericOps.go b/src/cmd/compile/internal/ssa/gen/genericOps.go
index 9786a71..6f8d10a 100644
--- a/src/cmd/compile/internal/ssa/gen/genericOps.go
+++ b/src/cmd/compile/internal/ssa/gen/genericOps.go
@@ -289,12 +289,13 @@
// Constant-like things
{name: "InitMem"}, // memory input to the function.
- {name: "Arg", aux: "SymOff", symEffect: "None"}, // argument to the function. aux=GCNode of arg, off = offset in that arg.
+ {name: "Arg", aux: "SymOff", symEffect: "Read"}, // argument to the function. aux=GCNode of arg, off = offset in that arg.
- // The address of a variable. arg0 is the base pointer (SB or SP, depending
- // on whether it is a global or stack variable). The Aux field identifies the
- // variable. It will be either an *ExternSymbol (with arg0=SB), *ArgSymbol (arg0=SP),
- // or *AutoSymbol (arg0=SP).
+ // The address of a variable. arg0 is the base pointer.
+ // If the variable is a global, the base pointer will be SB and
+ // the Aux field will be a *obj.LSym.
+ // If the variable is a local, the base pointer will be SP and
+ // the Aux field will be a *gc.Node.
{name: "Addr", argLength: 1, aux: "Sym", symEffect: "Addr"}, // Address of a variable. Arg0=SP or SB. Aux identifies the variable.
{name: "SP"}, // stack pointer
@@ -418,7 +419,7 @@
{name: "VarDef", argLength: 1, aux: "Sym", typ: "Mem", symEffect: "None"}, // aux is a *gc.Node of a variable that is about to be initialized. arg0=mem, returns mem
{name: "VarKill", argLength: 1, aux: "Sym", symEffect: "None"}, // aux is a *gc.Node of a variable that is known to be dead. arg0=mem, returns mem
- {name: "VarLive", argLength: 1, aux: "Sym", symEffect: "None"}, // aux is a *gc.Node of a variable that must be kept live. arg0=mem, returns mem
+ {name: "VarLive", argLength: 1, aux: "Sym", symEffect: "Read"}, // aux is a *gc.Node of a variable that must be kept live. arg0=mem, returns mem
{name: "KeepAlive", argLength: 2, typ: "Mem"}, // arg[0] is a value that must be kept alive until this mark. arg[1]=mem, returns mem
{name: "RegKill"}, // regalloc has determined that the value in this register is dead
