Implement break and continue (#55)

* #52 Update chapter8 to align with chapter7

* #52 Update chapter8 to align with chapter7

* #52 Fix spacing

* #51 get started on break and continue

* #51 get started on break and continue

* #51 more on break and continue

* #51 more on break and continue

* #51 more on break and continue

* #51 more on break and continue

* #51 more on break and continue

* #51 more on break and continue

* break & continue scopes are made lazily, and merged into as discovered

Drop ContBreak.
Drop ScopeNode.addScope.
Add a simple mergeScopes.
Simplify Region.inProgress; drop from child classes, use in Region.
Add a ConstantNode.XCONTROL shortcut.

* Fix some regressions

* Error on dead code after break/continue

* A more robust dead-def check

* Fix for dead loop-back path

* Fix scope shadowing bug with continue/break

Turn on LAZY phis by default; fix minor golden test results

* Fix a case with both break & continue

* #51 more on break and continue

* #51 more on break and continue

* #51 more on break and continue

* #51 fix erroneous push of scope

* #51 fix import

* #51 update test expected results

* #51 Start Chapter8 writeup

* #51 Start Chapter8 writeup

* #51 _scope needs killing after continue

* Add graph evaluator (#56)

* #51 wip writeup

* #51 wip writeup

* #51 wip writeup

* #51 wip writeup

* #51 wip writeup

* #51 update code comments / add assertion

* #51 revert assertion

* #51 evaluate graph to verify test outcome

* #51 add code snippets

* #51 add examples

* Cleanup README

Comment for usefullness of true Loops.
Try to distiguish `PhiNode` as the programming construct from `phi` as the mathematically SSA notation.
Flow long lines.
Remove LAZY flag, set as `true`.  Fold up true tests.

* minor comment

* #51 Check _breakScope is not null when parsing break or continue to detect use outside of loop

* #51 in parseComparison we need to move the op= version above the op version, since at this time using <= and >= does not work since they are parsed as > and < with a preceeding = which causes an error

* #51 Update main README to link to chapter 8

* Remove useless test

---------

Co-authored-by: Cliff Click <cliffc@acm.org>
Co-authored-by: XmiliaH <45106915+XmiliaH@users.noreply.github.com>

1 files changed, 103 insertions, 0 deletions

diff --git a/chapter08/docs/08-graph2.gv b/chapter08/docs/08-graph2.gv
new file mode 100644
index 00000000..2fa82523
--- /dev/null
+++ b/chapter08/docs/08-graph2.gv
@@ -0,0 +1,103 @@
+digraph chapter08 {
+/*
+while(arg < 10) {
+    arg = arg + 1;
+    if (arg == 5)
+        continue;
+    if (arg == 6)
+        continue;
+}
+return arg;
+
+*/
+	rankdir=BT;
+	ordering="in";
+	concentrate="true";
+	compound="true";
+	subgraph cluster_Nodes {
+		Start2 [ shape=plaintext label=<
+			<TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+			<TR><TD BGCOLOR="yellow">Start</TD></TR>
+			<TR><TD>
+				<TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+				<TR><TD PORT="p0" BGCOLOR="yellow">$ctrl</TD><TD PORT="p1">arg</TD></TR>
+				</TABLE>
+			</TD></TR>
+			</TABLE>>
+		];
+		Stop3 [ shape=box style=filled fillcolor=yellow label="Stop" ];
+		Loop6 [ shape=box style=filled fillcolor=yellow label="Loop" ];
+		Phi_arg8 [ style=filled fillcolor=lightyellow label="&phi;_arg" ];
+		Con_9 [ label="10" ];
+		LT10 [ label="<" ];
+		If11 [ shape=plaintext label=<
+			<TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+			<TR><TD BGCOLOR="yellow">If</TD></TR>
+			<TR><TD>
+				<TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+				<TR><TD PORT="p0" BGCOLOR="yellow">True</TD><TD PORT="p1" BGCOLOR="yellow">False</TD></TR>
+				</TABLE>
+			</TD></TR>
+			</TABLE>>
+		];
+		Con_15 [ label="1" ];
+		Add16 [ label="+" ];
+		Con_17 [ label="5" ];
+		EQ18 [ label="==" ];
+		If19 [ shape=plaintext label=<
+			<TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+			<TR><TD BGCOLOR="yellow">If</TD></TR>
+			<TR><TD>
+				<TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+				<TR><TD PORT="p0" BGCOLOR="yellow">True</TD><TD PORT="p1" BGCOLOR="yellow">False</TD></TR>
+				</TABLE>
+			</TD></TR>
+			</TABLE>>
+		];
+		Con_26 [ label="6" ];
+		EQ27 [ label="==" ];
+		If28 [ shape=plaintext label=<
+			<TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0" CELLPADDING="4">
+			<TR><TD BGCOLOR="yellow">If</TD></TR>
+			<TR><TD>
+				<TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
+				<TR><TD PORT="p0" BGCOLOR="yellow">True</TD><TD PORT="p1" BGCOLOR="yellow">False</TD></TR>
+				</TABLE>
+			</TD></TR>
+			</TABLE>>
+		];
+		Region34 [ shape=box style=filled fillcolor=yellow label="Region" ];
+		Region38 [ shape=box style=filled fillcolor=yellow label="Region" ];
+		Return39 [ shape=box style=filled fillcolor=yellow label="Return" ];
+		{ rank=same; Loop6;Phi_arg8;}
+		{ rank=same; Region34;}
+		{ rank=same; Region38;}
+	}
+	edge [ fontname=Helvetica, fontsize=8 ];
+	Stop3 -> Return39[taillabel=0 color=red];
+	Loop6 -> Start2:p0[taillabel=1 color=red];
+	Loop6 -> Region38[taillabel=2 color=red constraint=false];
+	Phi_arg8 -> Loop6 [style=dotted taillabel=0];
+	Phi_arg8 -> Start2:p1[taillabel=1];
+	Phi_arg8 -> Add16[taillabel=2 constraint=false];
+	LT10 -> Phi_arg8[taillabel=1];
+	LT10 -> Con_9[taillabel=2];
+	If11 -> Loop6[taillabel=0 color=red];
+	If11 -> LT10[taillabel=1];
+	Add16 -> Phi_arg8[taillabel=1];
+	Add16 -> Con_15[taillabel=2];
+	EQ18 -> Add16[taillabel=1];
+	EQ18 -> Con_17[taillabel=2];
+	If19 -> If11:p0[taillabel=0 color=red];
+	If19 -> EQ18[taillabel=1];
+	EQ27 -> Add16[taillabel=1];
+	EQ27 -> Con_26[taillabel=2];
+	If28 -> If19:p1[taillabel=0 color=red];
+	If28 -> EQ27[taillabel=1];
+	Region34 -> If19:p0[taillabel=1 color=red];
+	Region34 -> If28:p0[taillabel=2 color=red];
+	Region38 -> Region34[taillabel=1 color=red];
+	Region38 -> If28:p1[taillabel=2 color=red];
+	Return39 -> If11:p1[taillabel=0 color=red];
+	Return39 -> Phi_arg8[taillabel=1];
+}