Adding upstream version 1.21.8.upstream/1.21.8

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 289 insertions, 0 deletions

diff --git a/src/runtime/stkframe.go b/src/runtime/stkframe.go
new file mode 100644
index 0000000..5caacba
--- /dev/null
+++ b/src/runtime/stkframe.go
@@ -0,0 +1,289 @@
+// Copyright 2022 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.
+
+package runtime
+
+import (
+	"internal/abi"
+	"internal/goarch"
+	"runtime/internal/sys"
+	"unsafe"
+)
+
+// A stkframe holds information about a single physical stack frame.
+type stkframe struct {
+	// fn is the function being run in this frame. If there is
+	// inlining, this is the outermost function.
+	fn funcInfo
+
+	// pc is the program counter within fn.
+	//
+	// The meaning of this is subtle:
+	//
+	// - Typically, this frame performed a regular function call
+	//   and this is the return PC (just after the CALL
+	//   instruction). In this case, pc-1 reflects the CALL
+	//   instruction itself and is the correct source of symbolic
+	//   information.
+	//
+	// - If this frame "called" sigpanic, then pc is the
+	//   instruction that panicked, and pc is the correct address
+	//   to use for symbolic information.
+	//
+	// - If this is the innermost frame, then PC is where
+	//   execution will continue, but it may not be the
+	//   instruction following a CALL. This may be from
+	//   cooperative preemption, in which case this is the
+	//   instruction after the call to morestack. Or this may be
+	//   from a signal or an un-started goroutine, in which case
+	//   PC could be any instruction, including the first
+	//   instruction in a function. Conventionally, we use pc-1
+	//   for symbolic information, unless pc == fn.entry(), in
+	//   which case we use pc.
+	pc uintptr
+
+	// continpc is the PC where execution will continue in fn, or
+	// 0 if execution will not continue in this frame.
+	//
+	// This is usually the same as pc, unless this frame "called"
+	// sigpanic, in which case it's either the address of
+	// deferreturn or 0 if this frame will never execute again.
+	//
+	// This is the PC to use to look up GC liveness for this frame.
+	continpc uintptr
+
+	lr   uintptr // program counter at caller aka link register
+	sp   uintptr // stack pointer at pc
+	fp   uintptr // stack pointer at caller aka frame pointer
+	varp uintptr // top of local variables
+	argp uintptr // pointer to function arguments
+}
+
+// reflectMethodValue is a partial duplicate of reflect.makeFuncImpl
+// and reflect.methodValue.
+type reflectMethodValue struct {
+	fn     uintptr
+	stack  *bitvector // ptrmap for both args and results
+	argLen uintptr    // just args
+}
+
+// argBytes returns the argument frame size for a call to frame.fn.
+func (frame *stkframe) argBytes() uintptr {
+	if frame.fn.args != abi.ArgsSizeUnknown {
+		return uintptr(frame.fn.args)
+	}
+	// This is an uncommon and complicated case. Fall back to fully
+	// fetching the argument map to compute its size.
+	argMap, _ := frame.argMapInternal()
+	return uintptr(argMap.n) * goarch.PtrSize
+}
+
+// argMapInternal is used internally by stkframe to fetch special
+// argument maps.
+//
+// argMap.n is always populated with the size of the argument map.
+//
+// argMap.bytedata is only populated for dynamic argument maps (used
+// by reflect). If the caller requires the argument map, it should use
+// this if non-nil, and otherwise fetch the argument map using the
+// current PC.
+//
+// hasReflectStackObj indicates that this frame also has a reflect
+// function stack object, which the caller must synthesize.
+func (frame *stkframe) argMapInternal() (argMap bitvector, hasReflectStackObj bool) {
+	f := frame.fn
+	if f.args != abi.ArgsSizeUnknown {
+		argMap.n = f.args / goarch.PtrSize
+		return
+	}
+	// Extract argument bitmaps for reflect stubs from the calls they made to reflect.
+	switch funcname(f) {
+	case "reflect.makeFuncStub", "reflect.methodValueCall":
+		// These take a *reflect.methodValue as their
+		// context register and immediately save it to 0(SP).
+		// Get the methodValue from 0(SP).
+		arg0 := frame.sp + sys.MinFrameSize
+
+		minSP := frame.fp
+		if !usesLR {
+			// The CALL itself pushes a word.
+			// Undo that adjustment.
+			minSP -= goarch.PtrSize
+		}
+		if arg0 >= minSP {
+			// The function hasn't started yet.
+			// This only happens if f was the
+			// start function of a new goroutine
+			// that hasn't run yet *and* f takes
+			// no arguments and has no results
+			// (otherwise it will get wrapped in a
+			// closure). In this case, we can't
+			// reach into its locals because it
+			// doesn't have locals yet, but we
+			// also know its argument map is
+			// empty.
+			if frame.pc != f.entry() {
+				print("runtime: confused by ", funcname(f), ": no frame (sp=", hex(frame.sp), " fp=", hex(frame.fp), ") at entry+", hex(frame.pc-f.entry()), "\n")
+				throw("reflect mismatch")
+			}
+			return bitvector{}, false // No locals, so also no stack objects
+		}
+		hasReflectStackObj = true
+		mv := *(**reflectMethodValue)(unsafe.Pointer(arg0))
+		// Figure out whether the return values are valid.
+		// Reflect will update this value after it copies
+		// in the return values.
+		retValid := *(*bool)(unsafe.Pointer(arg0 + 4*goarch.PtrSize))
+		if mv.fn != f.entry() {
+			print("runtime: confused by ", funcname(f), "\n")
+			throw("reflect mismatch")
+		}
+		argMap = *mv.stack
+		if !retValid {
+			// argMap.n includes the results, but
+			// those aren't valid, so drop them.
+			n := int32((uintptr(mv.argLen) &^ (goarch.PtrSize - 1)) / goarch.PtrSize)
+			if n < argMap.n {
+				argMap.n = n
+			}
+		}
+	}
+	return
+}
+
+// getStackMap returns the locals and arguments live pointer maps, and
+// stack object list for frame.
+func (frame *stkframe) getStackMap(cache *pcvalueCache, debug bool) (locals, args bitvector, objs []stackObjectRecord) {
+	targetpc := frame.continpc
+	if targetpc == 0 {
+		// Frame is dead. Return empty bitvectors.
+		return
+	}
+
+	f := frame.fn
+	pcdata := int32(-1)
+	if targetpc != f.entry() {
+		// Back up to the CALL. If we're at the function entry
+		// point, we want to use the entry map (-1), even if
+		// the first instruction of the function changes the
+		// stack map.
+		targetpc--
+		pcdata = pcdatavalue(f, abi.PCDATA_StackMapIndex, targetpc, cache)
+	}
+	if pcdata == -1 {
+		// We do not have a valid pcdata value but there might be a
+		// stackmap for this function. It is likely that we are looking
+		// at the function prologue, assume so and hope for the best.
+		pcdata = 0
+	}
+
+	// Local variables.
+	size := frame.varp - frame.sp
+	var minsize uintptr
+	switch goarch.ArchFamily {
+	case goarch.ARM64:
+		minsize = sys.StackAlign
+	default:
+		minsize = sys.MinFrameSize
+	}
+	if size > minsize {
+		stackid := pcdata
+		stkmap := (*stackmap)(funcdata(f, abi.FUNCDATA_LocalsPointerMaps))
+		if stkmap == nil || stkmap.n <= 0 {
+			print("runtime: frame ", funcname(f), " untyped locals ", hex(frame.varp-size), "+", hex(size), "\n")
+			throw("missing stackmap")
+		}
+		// If nbit == 0, there's no work to do.
+		if stkmap.nbit > 0 {
+			if stackid < 0 || stackid >= stkmap.n {
+				// don't know where we are
+				print("runtime: pcdata is ", stackid, " and ", stkmap.n, " locals stack map entries for ", funcname(f), " (targetpc=", hex(targetpc), ")\n")
+				throw("bad symbol table")
+			}
+			locals = stackmapdata(stkmap, stackid)
+			if stackDebug >= 3 && debug {
+				print("      locals ", stackid, "/", stkmap.n, " ", locals.n, " words ", locals.bytedata, "\n")
+			}
+		} else if stackDebug >= 3 && debug {
+			print("      no locals to adjust\n")
+		}
+	}
+
+	// Arguments. First fetch frame size and special-case argument maps.
+	var isReflect bool
+	args, isReflect = frame.argMapInternal()
+	if args.n > 0 && args.bytedata == nil {
+		// Non-empty argument frame, but not a special map.
+		// Fetch the argument map at pcdata.
+		stackmap := (*stackmap)(funcdata(f, abi.FUNCDATA_ArgsPointerMaps))
+		if stackmap == nil || stackmap.n <= 0 {
+			print("runtime: frame ", funcname(f), " untyped args ", hex(frame.argp), "+", hex(args.n*goarch.PtrSize), "\n")
+			throw("missing stackmap")
+		}
+		if pcdata < 0 || pcdata >= stackmap.n {
+			// don't know where we are
+			print("runtime: pcdata is ", pcdata, " and ", stackmap.n, " args stack map entries for ", funcname(f), " (targetpc=", hex(targetpc), ")\n")
+			throw("bad symbol table")
+		}
+		if stackmap.nbit == 0 {
+			args.n = 0
+		} else {
+			args = stackmapdata(stackmap, pcdata)
+		}
+	}
+
+	// stack objects.
+	if (GOARCH == "amd64" || GOARCH == "arm64" || GOARCH == "ppc64" || GOARCH == "ppc64le" || GOARCH == "riscv64") &&
+		unsafe.Sizeof(abi.RegArgs{}) > 0 && isReflect {
+		// For reflect.makeFuncStub and reflect.methodValueCall,
+		// we need to fake the stack object record.
+		// These frames 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, abi.FUNCDATA_StackObjects)
+		if p != nil {
+			n := *(*uintptr)(p)
+			p = add(p, goarch.PtrSize)
+			r0 := (*stackObjectRecord)(noescape(p))
+			objs = unsafe.Slice(r0, int(n))
+			// Note: the noescape above is needed to keep
+			// getStackMap from "leaking param content:
+			// frame".  That leak propagates up to getgcmask, then
+			// GCMask, then verifyGCInfo, which converts the stack
+			// gcinfo tests into heap gcinfo tests :(
+		}
+	}
+
+	return
+}
+
+var methodValueCallFrameObjs [1]stackObjectRecord // initialized in stackobjectinit
+
+func stkobjinit() {
+	var abiRegArgsEface any = abi.RegArgs{}
+	abiRegArgsType := efaceOf(&abiRegArgsEface)._type
+	if abiRegArgsType.Kind_&kindGCProg != 0 {
+		throw("abiRegArgsType needs GC Prog, update methodValueCallFrameObjs")
+	}
+	// Set methodValueCallFrameObjs[0].gcdataoff so that
+	// stackObjectRecord.gcdata() will work correctly with it.
+	ptr := uintptr(unsafe.Pointer(&methodValueCallFrameObjs[0]))
+	var mod *moduledata
+	for datap := &firstmoduledata; datap != nil; datap = datap.next {
+		if datap.gofunc <= ptr && ptr < datap.end {
+			mod = datap
+			break
+		}
+	}
+	if mod == nil {
+		throw("methodValueCallFrameObjs is not in a module")
+	}
+	methodValueCallFrameObjs[0] = stackObjectRecord{
+		off:       -int32(alignUp(abiRegArgsType.Size_, 8)), // It's always the highest address local.
+		size:      int32(abiRegArgsType.Size_),
+		_ptrdata:  int32(abiRegArgsType.PtrBytes),
+		gcdataoff: uint32(uintptr(unsafe.Pointer(abiRegArgsType.GCData)) - mod.rodata),
+	}
+}