diff options
| -rw-r--r-- | src/cmd/compile/internal/abi/abiutils.go | 48 | ||||
| -rw-r--r-- | src/cmd/compile/internal/ssa/debug.go | 6 | ||||
| -rw-r--r-- | src/cmd/compile/internal/test/abiutils_test.go | 36 |
3 files changed, 90 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/abi/abiutils.go b/src/cmd/compile/internal/abi/abiutils.go index e192adb5e1..cb8e9d7b0f 100644 --- a/src/cmd/compile/internal/abi/abiutils.go +++ b/src/cmd/compile/internal/abi/abiutils.go @@ -790,3 +790,51 @@ func (state *assignState) assignParamOrReturn(pt *types.Type, n types.Object, is return state.stackAllocate(pt, n) } } + +// ComputePadding returns a list of "post element" padding values in +// the case where we have a structure being passed in registers. Give +// a param assignment corresponding to a struct, it returns a list of +// contaning padding values for each field, e.g. the Kth element in +// the list is the amount of padding between field K and the following +// field. For things that are not struct (or structs without padding) +// it returns a list of zeros. Example: +// +// type small struct { +// x uint16 +// y uint8 +// z int32 +// w int32 +// } +// +// For this struct we would return a list [0, 1, 0, 0], meaning that +// we have one byte of padding after the second field, and no bytes of +// padding after any of the other fields. Input parameter "storage" +// is with enough capacity to accommodate padding elements for +// the architected register set in question. +func (pa *ABIParamAssignment) ComputePadding(storage []uint64) []uint64 { + nr := len(pa.Registers) + padding := storage[:nr] + for i := 0; i < nr; i++ { + padding[i] = 0 + } + if pa.Type.Kind() != types.TSTRUCT || nr == 0 { + return padding + } + types := make([]*types.Type, 0, nr) + types = appendParamTypes(types, pa.Type) + if len(types) != nr { + panic("internal error") + } + off := int64(0) + for idx, t := range types { + ts := t.Size() + off += int64(ts) + if idx < len(types)-1 { + noff := align(off, types[idx+1]) + if noff != off { + padding[idx] = uint64(noff - off) + } + } + } + return padding +} diff --git a/src/cmd/compile/internal/ssa/debug.go b/src/cmd/compile/internal/ssa/debug.go index 4401f56703..ee522f41ef 100644 --- a/src/cmd/compile/internal/ssa/debug.go +++ b/src/cmd/compile/internal/ssa/debug.go @@ -1391,6 +1391,8 @@ func BuildFuncDebugNoOptimized(ctxt *obj.Link, f *Func, loggingEnabled bool, sta continue } rtypes, _ := inp.RegisterTypesAndOffsets() + padding := make([]uint64, 0, 32) + padding = inp.ComputePadding(padding) for k, r := range inp.Registers { reg := ObjRegForAbiReg(r, f.Config) dwreg := ctxt.Arch.DWARFRegisters[reg] @@ -1404,6 +1406,10 @@ func BuildFuncDebugNoOptimized(ctxt *obj.Link, f *Func, loggingEnabled bool, sta list = append(list, dwarf.DW_OP_piece) ts := rtypes[k].Width list = dwarf.AppendUleb128(list, uint64(ts)) + if padding[k] > 0 { + list = append(list, dwarf.DW_OP_piece) + list = dwarf.AppendUleb128(list, padding[k]) + } } } // fill in length of location expression element diff --git a/src/cmd/compile/internal/test/abiutils_test.go b/src/cmd/compile/internal/test/abiutils_test.go index daff99a799..b752c48612 100644 --- a/src/cmd/compile/internal/test/abiutils_test.go +++ b/src/cmd/compile/internal/test/abiutils_test.go @@ -14,6 +14,7 @@ import ( "cmd/internal/obj" "cmd/internal/obj/x86" "cmd/internal/src" + "fmt" "os" "testing" ) @@ -359,3 +360,38 @@ func TestABINumParamRegs(t *testing.T) { nrtest(t, a, 12) } + +func TestABIUtilsComputePadding(t *testing.T) { + // type s1 { f1 int8; f2 int16; f3 struct{}; f4 int32; f5 int64 } + i8 := types.Types[types.TINT8] + i16 := types.Types[types.TINT16] + i32 := types.Types[types.TINT32] + i64 := types.Types[types.TINT64] + emptys := mkstruct([]*types.Type{}) + s1 := mkstruct([]*types.Type{i8, i16, emptys, i32, i64}) + // func (p1 int32, p2 s1, p3 emptys, p4 [1]int32) + a1 := types.NewArray(i32, 1) + ft := mkFuncType(nil, []*types.Type{i32, s1, emptys, a1}, []*types.Type{}) + + // Run abitest() just to document what we're expected to see. + exp := makeExpectedDump(` + IN 0: R{ I0 } spilloffset: 0 typ: int32 + IN 1: R{ I1 I2 I3 I4 } spilloffset: 8 typ: struct { int8; int16; struct {}; int32; int64 } + IN 2: R{ } offset: 0 typ: struct {} + IN 3: R{ I5 } spilloffset: 24 typ: [1]int32 + offsetToSpillArea: 0 spillAreaSize: 32 +`) + abitest(t, ft, exp) + + // Analyze with full set of registers, then call ComputePadding + // on the second param, verifying the results. + regRes := configAMD64.ABIAnalyze(ft, false) + padding := make([]uint64, 32) + parm := regRes.InParams()[1] + padding = parm.ComputePadding(padding) + want := "[1 1 1 0]" + got := fmt.Sprintf("%+v", padding) + if got != want { + t.Errorf("padding mismatch: wanted %q got %q\n", got, want) + } +} |