cmd/compile: experiment which clobbers all dead pointer fields
The experiment "clobberdead" clobbers all pointer fields that the
compiler thinks are dead, just before and after every safepoint.
Useful for debugging the generation of live pointer bitmaps.
Helped find the following issues:
Update #15936
Update #16026
Update #16095
Update #18860
Change-Id: Id1d12f86845e3d93bae903d968b1eac61fc461f9
Reviewed-on: https://go-review.googlesource.com/23924
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
diff --git a/src/cmd/compile/internal/ssa/gen/genericOps.go b/src/cmd/compile/internal/ssa/gen/genericOps.go
index 300a545..e9a9096 100644
--- a/src/cmd/compile/internal/ssa/gen/genericOps.go
+++ b/src/cmd/compile/internal/ssa/gen/genericOps.go
@@ -314,7 +314,7 @@
// Return values appear on the stack. The method receiver, if any, is treated
// as a phantom first argument.
{name: "ClosureCall", argLength: 3, aux: "Int64", call: true}, // arg0=code pointer, arg1=context ptr, arg2=memory. auxint=arg size. Returns memory.
- {name: "StaticCall", argLength: 1, aux: "SymOff", call: true, symEffect: "None"}, // call function aux.(*gc.Sym), arg0=memory. auxint=arg size. Returns memory.
+ {name: "StaticCall", argLength: 1, aux: "SymOff", call: true, symEffect: "None"}, // call function aux.(*obj.LSym), arg0=memory. auxint=arg size. Returns memory.
{name: "InterCall", argLength: 2, aux: "Int64", call: true}, // interface call. arg0=code pointer, arg1=memory, auxint=arg size. Returns memory.
// Conversions: signed extensions, zero (unsigned) extensions, truncations
@@ -464,6 +464,9 @@
{name: "AtomicCompareAndSwap64", argLength: 4, typ: "(Bool,Mem)", hasSideEffects: true}, // if *arg0==arg1, then set *arg0=arg2. Returns true iff store happens and new memory.
{name: "AtomicAnd8", argLength: 3, typ: "Mem", hasSideEffects: true}, // *arg0 &= arg1. arg2=memory. Returns memory.
{name: "AtomicOr8", argLength: 3, typ: "Mem", hasSideEffects: true}, // *arg0 |= arg1. arg2=memory. Returns memory.
+
+ // Clobber experiment op
+ {name: "Clobber", argLength: 0, typ: "Void", aux: "SymOff", symEffect: "None"}, // write an invalid pointer value to the given pointer slot of a stack variable
}
// kind control successors implicit exit
