diff options
| author | melonedo <funanzeng@gmail.com> | 2022-09-19 16:01:04 +0800 |
|---|---|---|
| committer | Ian Lance Taylor <iant@golang.org> | 2022-09-27 09:28:39 -0700 |
| commit | f38162977e2b7efaa75233a0cba2a30a2b7f5132 (patch) | |
| tree | fe1805c24a4ce17d6d50af1ed31d23cb29ae935e | |
| parent | 0b2706ac0e6d6b990d789325f9e081dfe4501f4f (diff) | |
| download | gcc-f38162977e2b7efaa75233a0cba2a30a2b7f5132.zip gcc-f38162977e2b7efaa75233a0cba2a30a2b7f5132.tar.gz gcc-f38162977e2b7efaa75233a0cba2a30a2b7f5132.tar.bz2 | |
runtime: synchronize empty struct field handling
In GCCGO and gollvm, the logic for allocating one byte for the last field is:
1. the last field has zero size
2. the struct itself does not have zero size
3. the last field is not blank
this commit adds the last two conditions to runtime.structToFFI.
For golang/go#55146
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/431735
| -rw-r--r-- | gcc/go/gofrontend/MERGE | 2 | ||||
| -rw-r--r-- | libgo/go/runtime/ffi.go | 14 |
2 files changed, 11 insertions, 5 deletions
diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE index f7a7985..73aa712 100644 --- a/gcc/go/gofrontend/MERGE +++ b/gcc/go/gofrontend/MERGE @@ -1,4 +1,4 @@ -42efec8c126cf3787bc7c89d9c7f224eff7c5a21 +0140cca9bc0fad1108c7ed369376ac71cc4bfecf The first line of this file holds the git revision number of the last merge done from the gofrontend repository. diff --git a/libgo/go/runtime/ffi.go b/libgo/go/runtime/ffi.go index cd8479e..86ce5b8 100644 --- a/libgo/go/runtime/ffi.go +++ b/libgo/go/runtime/ffi.go @@ -4,6 +4,7 @@ // Only build this file if libffi is supported. +//go:build libffi // +build libffi package runtime @@ -221,9 +222,6 @@ func stringToFFI() *__ffi_type { // structToFFI returns an ffi_type for a Go struct type. func structToFFI(typ *structtype) *__ffi_type { c := len(typ.fields) - if c == 0 { - return emptyStructToFFI() - } if typ.typ.kind&kindDirectIface != 0 { return ffi_type_pointer() } @@ -231,6 +229,7 @@ func structToFFI(typ *structtype) *__ffi_type { fields := make([]*__ffi_type, 0, c+1) checkPad := false lastzero := false + sawnonzero := false for i, v := range typ.fields { // Skip zero-sized fields; they confuse libffi, // and there is no value to pass in any case. @@ -239,10 +238,13 @@ func structToFFI(typ *structtype) *__ffi_type { // next field. if v.typ.size == 0 { checkPad = true - lastzero = true + if v.name == nil || *v.name != "_" { + lastzero = true + } continue } lastzero = false + sawnonzero = true if checkPad { off := uintptr(0) @@ -263,6 +265,10 @@ func structToFFI(typ *structtype) *__ffi_type { fields = append(fields, typeToFFI(v.typ)) } + if !sawnonzero { + return emptyStructToFFI() + } + if lastzero { // The compiler adds one byte padding to non-empty struct ending // with a zero-sized field (types.cc:get_backend_struct_fields). |