1 files changed, 131 insertions, 0 deletions
diff --git a/src/cmd/internal/obj/inl.go b/src/cmd/internal/obj/inl.go
new file mode 100644
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+++ b/src/cmd/internal/obj/inl.go
@@ -0,0 +1,131 @@
+// Copyright 2017 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 obj
+
+import "cmd/internal/src"
+
+// InlTree is a collection of inlined calls. The Parent field of an
+// InlinedCall is the index of another InlinedCall in InlTree.
+//
+// The compiler maintains a global inlining tree and adds a node to it
+// every time a function is inlined. For example, suppose f() calls g()
+// and g has two calls to h(), and that f, g, and h are inlineable:
+//
+//  1 func main() {
+//  2     f()
+//  3 }
+//  4 func f() {
+//  5     g()
+//  6 }
+//  7 func g() {
+//  8     h()
+//  9     h()
+// 10 }
+// 11 func h() {
+// 12     println("H")
+// 13 }
+//
+// Assuming the global tree starts empty, inlining will produce the
+// following tree:
+//
+//   []InlinedCall{
+//     {Parent: -1, Func: "f", Pos: <line 2>},
+//     {Parent:  0, Func: "g", Pos: <line 5>},
+//     {Parent:  1, Func: "h", Pos: <line 8>},
+//     {Parent:  1, Func: "h", Pos: <line 9>},
+//   }
+//
+// The nodes of h inlined into main will have inlining indexes 2 and 3.
+//
+// Eventually, the compiler extracts a per-function inlining tree from
+// the global inlining tree (see pcln.go).
+type InlTree struct {
+	nodes []InlinedCall
+}
+
+// InlinedCall is a node in an InlTree.
+type InlinedCall struct {
+	Parent   int      // index of the parent in the InlTree or < 0 if outermost call
+	Pos      src.XPos // position of the inlined call
+	Func     *LSym    // function that was inlined
+	ParentPC int32    // PC of instruction just before inlined body. Only valid in local trees.
+}
+
+// Add adds a new call to the tree, returning its index.
+func (tree *InlTree) Add(parent int, pos src.XPos, func_ *LSym) int {
+	r := len(tree.nodes)
+	call := InlinedCall{
+		Parent: parent,
+		Pos:    pos,
+		Func:   func_,
+	}
+	tree.nodes = append(tree.nodes, call)
+	return r
+}
+
+func (tree *InlTree) Parent(inlIndex int) int {
+	return tree.nodes[inlIndex].Parent
+}
+
+func (tree *InlTree) InlinedFunction(inlIndex int) *LSym {
+	return tree.nodes[inlIndex].Func
+}
+
+func (tree *InlTree) CallPos(inlIndex int) src.XPos {
+	return tree.nodes[inlIndex].Pos
+}
+
+func (tree *InlTree) setParentPC(inlIndex int, pc int32) {
+	tree.nodes[inlIndex].ParentPC = pc
+}
+
+// OutermostPos returns the outermost position corresponding to xpos,
+// which is where xpos was ultimately inlined to. In the example for
+// InlTree, main() contains inlined AST nodes from h(), but the
+// outermost position for those nodes is line 2.
+func (ctxt *Link) OutermostPos(xpos src.XPos) src.Pos {
+	pos := ctxt.InnermostPos(xpos)
+
+	outerxpos := xpos
+	for ix := pos.Base().InliningIndex(); ix >= 0; {
+		call := ctxt.InlTree.nodes[ix]
+		ix = call.Parent
+		outerxpos = call.Pos
+	}
+	return ctxt.PosTable.Pos(outerxpos)
+}
+
+// InnermostPos returns the innermost position corresponding to xpos,
+// that is, the code that is inlined and that inlines nothing else.
+// In the example for InlTree above, the code for println within h
+// would have an innermost position with line number 12, whether
+// h was not inlined, inlined into g, g-then-f, or g-then-f-then-main.
+// This corresponds to what someone debugging main, f, g, or h might
+// expect to see while single-stepping.
+func (ctxt *Link) InnermostPos(xpos src.XPos) src.Pos {
+	return ctxt.PosTable.Pos(xpos)
+}
+
+// AllPos returns a slice of the positions inlined at xpos, from
+// innermost (index zero) to outermost.  To avoid gratuitous allocation
+// the result is passed in and extended if necessary.
+func (ctxt *Link) AllPos(xpos src.XPos, result []src.Pos) []src.Pos {
+	pos := ctxt.InnermostPos(xpos)
+	result = result[:0]
+	result = append(result, ctxt.PosTable.Pos(xpos))
+	for ix := pos.Base().InliningIndex(); ix >= 0; {
+		call := ctxt.InlTree.nodes[ix]
+		ix = call.Parent
+		result = append(result, ctxt.PosTable.Pos(call.Pos))
+	}
+	return result
+}
+
+func dumpInlTree(ctxt *Link, tree InlTree) {
+	for i, call := range tree.nodes {
+		pos := ctxt.PosTable.Pos(call.Pos)
+		ctxt.Logf("%0d | %0d | %s (%s) pc=%d\n", i, call.Parent, call.Func, pos, call.ParentPC)
+	}
+}