From 3304b2235af0a88ba0bb21edaf2c60df47b6e0a8 Mon Sep 17 00:00:00 2001 From: Austin Clements Date: Wed, 31 Mar 2021 16:40:52 -0400 Subject: [PATCH] cmd/compile: fix incoming ABI with GOEXPERIMENT=regabiargs When regabiargs is enabled, a function's incoming ABI should be determined solely by the function's own definition ABI (which is usually ABIInternal, but can be ABI0 for ABI wrappers). For example, the current code miscompiles ABI0 -> ABIInternal wrappers when the experiment is enabled because it treats the wrapper itself as being called as ABIInternal. This causes it to assume the incoming arguments are already in registers, so usually the wrapper doesn't do anything with the arguments because it thinks they're already in the right place. With this fix, these wrappers now correctly load the arguments from the stack and put them in registers. For #40724. Change-Id: Iec784e88ebc55d9e95e830ed7533aa336f3b1ca2 Reviewed-on: https://go-review.googlesource.com/c/go/+/306409 Trust: Austin Clements Run-TryBot: Austin Clements TryBot-Result: Go Bot Reviewed-by: Than McIntosh Reviewed-by: Cherry Zhang --- src/cmd/compile/internal/ssagen/ssa.go | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go index 57099371e6..aaea732057 100644 --- a/src/cmd/compile/internal/ssagen/ssa.go +++ b/src/cmd/compile/internal/ssagen/ssa.go @@ -225,13 +225,26 @@ const magicNameDotSuffix = ".MagicMethodNameForTestingRegisterABI" const magicLastTypeName = "MagicLastTypeNameForTestingRegisterABI" // abiForFunc implements ABI policy for a function, but does not return a copy of the ABI. -// Passing a nil function returns ABIInternal. +// Passing a nil function returns the default ABI based on experiment configuration. func abiForFunc(fn *ir.Func, abi0, abi1 *abi.ABIConfig) *abi.ABIConfig { - a := abi1 - if !regabiEnabledForAllCompilation() { - a = abi0 + if objabi.Experiment.RegabiArgs { + // Select the ABI based on the function's defining ABI. + if fn == nil { + return abi1 + } + switch fn.ABI { + case obj.ABI0: + return abi0 + case obj.ABIInternal: + // TODO(austin): Clean up the nomenclature here. + // It's not clear that "abi1" is ABIInternal. + return abi1 + } + base.Fatalf("function %v has unknown ABI %v", fn, fn.ABI) + panic("not reachable") } + a := abi0 if fn != nil { name := ir.FuncName(fn) magicName := strings.HasSuffix(name, magicNameDotSuffix) @@ -263,10 +276,6 @@ func regAbiForFuncType(ft *types.Func) bool { return np > 0 && strings.Contains(ft.Params.FieldType(np-1).String(), magicLastTypeName) } -func regabiEnabledForAllCompilation() bool { - return objabi.Experiment.RegabiArgs -} - // getParam returns the Field of ith param of node n (which is a // function/method/interface call), where the receiver of a method call is // considered as the 0th parameter. This does not include the receiver of an -- 2.50.0