reflect,runtime: add reflect support for regabi on PPC64

This adds the regabi support needed for reflect including:
- implementation of the makeFuncSub and methodValueCall for
reflect
- implementations of archFloat32FromReg and archFloat32ToReg
needed for PPC64 due to differences in the way float32 are
represented in registers as compared to other platforms
- change needed to stack.go due to the functions that are
changed above

Change-Id: Ida40d831370e39b91711ccb9616492b7fad3debf
Reviewed-on: https://go-review.googlesource.com/c/go/+/352429
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Lynn Boger <laboger@linux.vnet.ibm.com>

diff --git a/src/reflect/asm_ppc64x.s b/src/reflect/asm_ppc64x.s
index d955e4110f8b789afaa0a90a3b25457a607bdf40..1ccfb25b94141be9959852943f574696a89a7481 100644 (file)
--- a/src/reflect/asm_ppc64x.s
+++ b/src/reflect/asm_ppc64x.s
@@ -9,34 +9,76 @@
 #include "funcdata.h"
 #include "asm_ppc64x.h"
 
+// The frames of each of the two functions below contain two locals, at offsets
+// that are known to the runtime.
+//
+// The first local is a bool called retValid with a whole pointer-word reserved
+// for it on the stack. The purpose of this word is so that the runtime knows
+// whether the stack-allocated return space contains valid values for stack
+// scanning.
+//
+// The second local is an abi.RegArgs value whose offset is also known to the
+// runtime, so that a stack map for it can be constructed, since it contains
+// pointers visible to the GC.
+
+#define LOCAL_RETVALID 32+FIXED_FRAME
+#define LOCAL_REGARGS 40+FIXED_FRAME
+
+// The frame size of the functions below is
+// 32 (args of callReflect) + 8 (bool + padding) + 296 (abi.RegArgs) = 336.
+
 // makeFuncStub is the code half of the function returned by MakeFunc.
 // See the comment on the declaration of makeFuncStub in makefunc.go
 // for more details.
 // No arg size here, runtime pulls arg map out of the func value.
-TEXT ·makeFuncStub(SB),(NOSPLIT|WRAPPER),$40
+TEXT ·makeFuncStub(SB),(NOSPLIT|WRAPPER),$336
        NO_LOCAL_POINTERS
-       MOVD    R11, FIXED_FRAME+0(R1)
-       MOVD    $argframe+0(FP), R3
-       MOVD    R3, FIXED_FRAME+8(R1)
-       MOVB    R0, FIXED_FRAME+32(R1)
-       ADD     $FIXED_FRAME+32, R1, R3
-       MOVD    R3, FIXED_FRAME+16(R1)
-       MOVD    R0, FIXED_FRAME+24(R1)
+       // NO_LOCAL_POINTERS is a lie. The stack map for the two locals in this
+       // frame is specially handled in the runtime. See the comment above LOCAL_RETVALID.
+       ADD     $LOCAL_REGARGS, R1, R20
+       CALL    runtime·spillArgs(SB)
+       MOVD    R11, FIXED_FRAME+32(R1) // save R11
+       MOVD    R11, FIXED_FRAME+0(R1)  // arg for moveMakeFuncArgPtrs
+       MOVD    R20, FIXED_FRAME+8(R1)  // arg for local args
+       CALL    ·moveMakeFuncArgPtrs(SB)
+       MOVD    FIXED_FRAME+32(R1), R11 // restore R11 ctxt
+       MOVD    R11, FIXED_FRAME+0(R1)  // ctxt (arg0)
+       MOVD    $argframe+0(FP), R3     // save arg to callArg
+       MOVD    R3, FIXED_FRAME+8(R1)   // frame (arg1)
+       ADD     $LOCAL_RETVALID, R1, R3 // addr of return flag
+       MOVB    R0, (R3)                // clear flag
+       MOVD    R3, FIXED_FRAME+16(R1)  // addr retvalid (arg2)
+       ADD     $LOCAL_REGARGS, R1, R3
+       MOVD    R3, FIXED_FRAME+24(R1)  // abiregargs (arg3)
        BL      ·callReflect(SB)
+       ADD     $LOCAL_REGARGS, R1, R20 // set address of spill area
+       CALL    runtime·unspillArgs(SB)
        RET
 
 // methodValueCall is the code half of the function returned by makeMethodValue.
 // See the comment on the declaration of methodValueCall in makefunc.go
 // for more details.
 // No arg size here; runtime pulls arg map out of the func value.
-TEXT ·methodValueCall(SB),(NOSPLIT|WRAPPER),$40
+TEXT ·methodValueCall(SB),(NOSPLIT|WRAPPER),$336
        NO_LOCAL_POINTERS
-       MOVD    R11, FIXED_FRAME+0(R1)
-       MOVD    $argframe+0(FP), R3
-       MOVD    R3, FIXED_FRAME+8(R1)
-       MOVB    R0, FIXED_FRAME+32(R1)
-       ADD     $FIXED_FRAME+32, R1, R3
-       MOVD    R3, FIXED_FRAME+16(R1)
-       MOVD    R0, FIXED_FRAME+24(R1)
+       // NO_LOCAL_POINTERS is a lie. The stack map for the two locals in this
+       // frame is specially handled in the runtime. See the comment above LOCAL_RETVALID.
+       ADD     $LOCAL_REGARGS, R1, R20
+       CALL    runtime·spillArgs(SB)
+       MOVD    R11, FIXED_FRAME+0(R1) // arg0 ctxt
+       MOVD    R11, FIXED_FRAME+32(R1) // save for later
+       MOVD    R20, FIXED_FRAME+8(R1) // arg1 abiregargs
+       CALL    ·moveMakeFuncArgPtrs(SB)
+       MOVD    FIXED_FRAME+32(R1), R11 // restore ctxt
+       MOVD    R11, FIXED_FRAME+0(R1) // set as arg0
+       MOVD    $argframe+0(FP), R3     // frame pointer
+       MOVD    R3, FIXED_FRAME+8(R1)   // set as arg1
+       ADD     $LOCAL_RETVALID, R1, R3
+       MOVB    $0, (R3)                // clear ret flag
+       MOVD    R3, FIXED_FRAME+16(R1)  // addr of return flag
+       ADD     $LOCAL_REGARGS, R1, R3  // addr of abiregargs
+       MOVD    R3, FIXED_FRAME+24(R1)  // set as arg3
        BL      ·callMethod(SB)
+       ADD     $LOCAL_REGARGS, R1, R20
+       CALL    runtime·unspillArgs(SB)
        RET

diff --git a/src/reflect/float32reg_generic.go b/src/reflect/float32reg_generic.go
index 381d458057488cb574da99f07fb857728c1b3508..bfceb9ecaa22be2e5ebbd5609fd93c166b80312a 100644 (file)
--- a/src/reflect/float32reg_generic.go
+++ b/src/reflect/float32reg_generic.go
@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !ppc64 && !ppc64le
+// +build !ppc64,!ppc64le
+
 package reflect
 
 import "unsafe"

diff --git a/src/reflect/float32reg_ppc64x.s b/src/reflect/float32reg_ppc64x.s
new file mode 100644 (file)
index 0000000..391edfa
--- /dev/null
+++ b/src/reflect/float32reg_ppc64x.s
@@ -0,0 +1,31 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build ppc64 || ppc64le
+// +build ppc64 ppc64le
+
+#include "textflag.h"
+
+// On PPC64, the float32 becomes a float64
+// when loaded in a register, different from
+// other platforms. These functions are
+// needed to ensure correct conversions on PPC64.
+
+// Convert float32->uint64
+TEXT ·archFloat32ToReg(SB),NOSPLIT,$0-16
+       FMOVS   val+0(FP), F1
+       FMOVD   F1, ret+8(FP)
+       RET
+
+// Convert uint64->float32
+TEXT ·archFloat32FromReg(SB),NOSPLIT,$0-12
+       FMOVD   reg+0(FP), F1
+       // Normally a float64->float32 conversion
+       // would need rounding, but that is not needed
+       // here since the uint64 was originally converted
+       // from float32, and should be avoided to
+       // preserve SNaN values.
+       FMOVS   F1, ret+8(FP)
+       RET
+

diff --git a/src/reflect/stubs_ppc64x.go b/src/reflect/stubs_ppc64x.go
new file mode 100644 (file)
index 0000000..dbd3f9e
--- /dev/null
+++ b/src/reflect/stubs_ppc64x.go
@@ -0,0 +1,11 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build ppc64le || ppc64
+// +build ppc64le ppc64
+
+package reflect
+
+func archFloat32FromReg(reg uint64) float32
+func archFloat32ToReg(val float32) uint64

diff --git a/src/runtime/stack.go b/src/runtime/stack.go
index cccec49f8e22cb8a32ba2c67b5153a8645aa88c4..22fff73947d680d56a1ab833a37b1e04e72c173f 100644 (file)
--- a/src/runtime/stack.go
+++ b/src/runtime/stack.go
@@ -1316,7 +1316,7 @@ func getStackMap(frame *stkframe, cache *pcvalueCache, debug bool) (locals, args
        }
 
        // stack objects.
-       if (GOARCH == "amd64" || GOARCH == "arm64") && unsafe.Sizeof(abi.RegArgs{}) > 0 && frame.argmap != nil {
+       if (GOARCH == "amd64" || GOARCH == "arm64" || GOARCH == "ppc64" || GOARCH == "ppc64le") && unsafe.Sizeof(abi.RegArgs{}) > 0 && frame.argmap != nil {
                // argmap is set when the function is reflect.makeFuncStub or reflect.methodValueCall.
                // We don't actually use argmap in this case, but we need to fake the stack object
                // record for these frames which contain an internal/abi.RegArgs at a hard-coded offset.