[dev.typeparams] reflect: implement register ABI for MakeFunc etc. on ARM64

Implement register ABI for reflect.MakeFunc and method Value Call
on ARM64.

Change-Id: I5487febb9ea764af5ccf5d7c94858ab0acec7cac
Reviewed-on: https://go-review.googlesource.com/c/go/+/323936
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

diff --git a/src/reflect/asm_arm64.s b/src/reflect/asm_arm64.s
index 5fe88e27e400d24bb97d2c57c5f58c7d95248c46..5b9b3573fa2a7e721e482cfe61b91dbf25552e62 100644 (file)
--- a/src/reflect/asm_arm64.s
+++ b/src/reflect/asm_arm64.s
@@ -5,34 +5,75 @@
 #include "textflag.h"
 #include "funcdata.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 40
+#define LOCAL_REGARGS 48
+
+// The frame size of the functions below is
+// 32 (args of callReflect) + 8 (bool + padding) + 392 (abi.RegArgs) = 432.
+
 // 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),$432
        NO_LOCAL_POINTERS
+       // 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, RSP, R20
+       CALL    runtime·spillArgs(SB)
+       MOVD    R26, 32(RSP) // outside of moveMakeFuncArgPtrs's arg area
+       MOVD    R26, 8(RSP)
+       MOVD    R20, 16(RSP)
+       CALL    ·moveMakeFuncArgPtrs(SB)
+       MOVD    32(RSP), R26
        MOVD    R26, 8(RSP)
        MOVD    $argframe+0(FP), R3
        MOVD    R3, 16(RSP)
-       MOVB    $0, 40(RSP)
-       ADD     $40, RSP, R3
+       MOVB    $0, LOCAL_RETVALID(RSP)
+       ADD     $LOCAL_RETVALID, RSP, R3
        MOVD    R3, 24(RSP)
-       MOVD    $0, 32(RSP)
-       BL      ·callReflect(SB)
+       ADD     $LOCAL_REGARGS, RSP, R3
+       MOVD    R3, 32(RSP)
+       CALL    ·callReflect(SB)
+       ADD     $LOCAL_REGARGS, RSP, R20
+       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),$432
        NO_LOCAL_POINTERS
+       // 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, RSP, R20
+       CALL    runtime·spillArgs(SB)
+       MOVD    R26, 32(RSP) // outside of moveMakeFuncArgPtrs's arg area
+       MOVD    R26, 8(RSP)
+       MOVD    R20, 16(RSP)
+       CALL    ·moveMakeFuncArgPtrs(SB)
+       MOVD    32(RSP), R26
        MOVD    R26, 8(RSP)
        MOVD    $argframe+0(FP), R3
        MOVD    R3, 16(RSP)
-       MOVB    $0, 40(RSP)
-       ADD     $40, RSP, R3
+       MOVB    $0, LOCAL_RETVALID(RSP)
+       ADD     $LOCAL_RETVALID, RSP, R3
        MOVD    R3, 24(RSP)
-       MOVD    $0, 32(RSP)
-       BL      ·callMethod(SB)
+       ADD     $LOCAL_REGARGS, RSP, R3
+       MOVD    R3, 32(RSP)
+       CALL    ·callMethod(SB)
+       ADD     $LOCAL_REGARGS, RSP, R20
+       CALL    runtime·unspillArgs(SB)
        RET

diff --git a/src/runtime/stack.go b/src/runtime/stack.go
index 622de45f25a3fb2d19c05bcfbe731acc620f8e86..a1182b00bdc152ff02835da1bf2c07c6816244b8 100644 (file)
--- a/src/runtime/stack.go
+++ b/src/runtime/stack.go
@@ -1318,11 +1318,11 @@ func getStackMap(frame *stkframe, cache *pcvalueCache, debug bool) (locals, args
        }
 
        // stack objects.
-       if GOARCH == "amd64" && unsafe.Sizeof(abi.RegArgs{}) > 0 && frame.argmap != nil {
+       if (GOARCH == "amd64" || GOARCH == "arm64") && 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
-               // on amd64.
+               // record for these frames which contain an internal/abi.RegArgs at a hard-coded offset.
+               // This offset matches the assembly code on amd64 and arm64.
                objs = methodValueCallFrameObjs
        } else {
                p := funcdata(f, _FUNCDATA_StackObjects)