[dev.ssa] cmd/runtime: generate gc bitmaps for SSA-compiled code
This change is all about leveraging the gc bitmap generation
that is already done by the current compiler. We rearrange how
stack allocation is done so that we generate a variable declaration
for each spill. We also reorganize how args/locals are recorded
during SSA. Then we can use the existing allocauto/defframe to
allocate the stack frame and liveness to make the gc bitmaps.
With this change, stack copying works correctly and we no longer
need hacks in runtime/stack*.go to make tests work. GC is close
to working, it just needs write barriers.
Change-Id: I990fb4e3fbe98850c6be35c3185a1c85d9e1a6ba
Reviewed-on: https://go-review.googlesource.com/13894
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
diff --git a/src/cmd/compile/internal/ssa/gen/genericOps.go b/src/cmd/compile/internal/ssa/gen/genericOps.go
index 8cd8165..81fe205 100644
--- a/src/cmd/compile/internal/ssa/gen/genericOps.go
+++ b/src/cmd/compile/internal/ssa/gen/genericOps.go
@@ -278,8 +278,8 @@
// Function calls. Arguments to the call have already been written to the stack.
// Return values appear on the stack. The method receiver, if any, is treated
// as a phantom first argument.
- {name: "ClosureCall"}, // arg0=code pointer, arg1=context ptr, arg2=memory. Returns memory.
- {name: "StaticCall"}, // call function aux.(*gc.Sym), arg0=memory. Returns memory.
+ {name: "ClosureCall"}, // arg0=code pointer, arg1=context ptr, arg2=memory. auxint=arg size. Returns memory.
+ {name: "StaticCall"}, // call function aux.(*gc.Sym), arg0=memory. auxint=arg size. Returns memory.
// Conversions: signed extensions, zero (unsigned) extensions, truncations
{name: "SignExt8to16", typ: "Int16"},
@@ -359,6 +359,9 @@
// Used during ssa construction. Like Copy, but the arg has not been specified yet.
{name: "FwdRef"},
+
+ {name: "VarDef"}, // aux is a *gc.Node of a variable that is about to be initialized. arg0=mem, returns mem
+ {name: "VarKill"}, // aux is a *gc.Node of a variable that is known to be dead. arg0=mem, returns mem
}
// kind control successors
