"default main" requires a `return expr`, or else its just dead.

Empty program can make an empty elf.
Bug ShlNode losing precision.

10 files changed, 27 insertions, 14 deletions

diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter09Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter09Test.java
index 401f346f..a4aade16 100644
--- a/chapter22/src/test/java/com/seaofnodes/simple/Chapter09Test.java
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter09Test.java
@@ -128,14 +128,14 @@ while(v1+arg) {
 }
                 """);
         code.parse().opto();
-        assertEquals("return 0;", code.print());
+        assertEquals("Stop[ ]", code.print());
     }
 
     @Test
     public void testWhile0() {
-        CodeGen code = new CodeGen("while(0) continue; if(0) arg=0;");
+        CodeGen code = new CodeGen("while(0) continue; if(0) arg=0; return arg;");
         code.parse().opto();
-        assertEquals("return 0;", code.print());
+        assertEquals("return arg;", code.print());
     }
 
     @Test
@@ -145,6 +145,7 @@ if(0) while(0) {
     int arg=arg;
     while(0) {}
 }
+return 0;
 """);
         code.parse().opto();
         assertEquals("return 0;", code.print());
@@ -221,7 +222,7 @@ while(1) {
 }
 """);
         code.parse().opto();
-        assertEquals("return Top;", code.print());
+        assertEquals("Stop[ ]", code.print());
     }
 
     @Test
@@ -255,7 +256,7 @@ while(0==1) while(v0)
         v0=1+v0;
 """);
         code.parse().opto();
-        assertEquals("return 0;", code.print());
+        assertEquals("Stop[ ]", code.print());
     }
 
     @Test
@@ -271,7 +272,7 @@ while(1)
 return v1+v0;
                                    """);
         code.parse().opto();
-        assertEquals("return Top;", code.print());
+        assertEquals("Stop[ ]", code.print());
     }
 
     @Test
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter10Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter10Test.java
index 1253e4a6..b7d65b95 100644
--- a/chapter22/src/test/java/com/seaofnodes/simple/Chapter10Test.java
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter10Test.java
@@ -304,6 +304,7 @@ if(0) {
         v0=v2;
     }
 }
+return 0;
    """);
         code.parse().opto();
         assertEquals("return 0;", code.print());
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter11Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter11Test.java
index f6539ac4..1fb9f75a 100644
--- a/chapter22/src/test/java/com/seaofnodes/simple/Chapter11Test.java
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter11Test.java
@@ -435,7 +435,7 @@ while(1)
   arg = arg+ptr.v;
 """);
         code.parse().opto();
-        assertEquals("return Top;", code.print());
+        assertEquals("Stop[ ]", code.print());
     }
 
     @Test
@@ -527,7 +527,7 @@ while(0>=0) {
 return 0;
 """);
         code.parse().opto();
-        assertEquals("return Top;", code.print());
+        assertEquals("Stop[ ]", code.print());
     }
 
     @Test
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter13Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter13Test.java
index 6bf45a22..a4644917 100644
--- a/chapter22/src/test/java/com/seaofnodes/simple/Chapter13Test.java
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter13Test.java
@@ -130,7 +130,7 @@ return n.i;
 
     @Test
     public void testNullRef4() {
-        CodeGen code = new CodeGen("-null-5/null-5;");
+        CodeGen code = new CodeGen("return -null-5/null-5;");
         try { code.parse().opto().typeCheck(); fail(); }
         catch( Exception e ) { assertEquals("Cannot 'Add' null",e.getMessage()); }
     }
@@ -146,6 +146,7 @@ return n.i;
         CodeGen code = new CodeGen(
 """
 struct S{};
+return 0;
 """);
         code.parse().opto();
         assertEquals("return 0;", code.print());
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter15Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter15Test.java
index 8b138b46..cebbf4a0 100644
--- a/chapter22/src/test/java/com/seaofnodes/simple/Chapter15Test.java
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter15Test.java
@@ -323,6 +323,7 @@ while(0) {}
 u32 v7=0;
 int v8=0;
 while(0<--1>>>---(v7*0==v8)) {}
+return 0;
 """);
         code.parse().opto();
         assertEquals("return 0;", code.print());
@@ -347,6 +348,7 @@ else {
             }
         }
 }
+return 0;
 """);
         code.parse().opto();
         assertEquals("return 0;", code.print());
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter18Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter18Test.java
index c0e28412..9c8ad66c 100644
--- a/chapter22/src/test/java/com/seaofnodes/simple/Chapter18Test.java
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter18Test.java
@@ -214,7 +214,7 @@ val fcn = { Person?[] ps, int x ->
 var ps = new Person?[2];
 ps[0] = new Person;
 ps[1] = new Person;
-fcn(ps,1);
+return fcn(ps,1);
 """);
         code.driver(Phase.LocalSched);
         assertEquals("return 0;", code._stop.toString());
@@ -249,6 +249,7 @@ for(;;) {
     if (i2i(2) == arg) break;
     i2i = null;
 }
+return 0;
 """);
         try { code.parse().opto().typeCheck(); fail(); }
         catch( Exception e ) { assertEquals("Might be null calling { int -> int #1}?",e.getMessage()); }
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter19Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter19Test.java
index bce75c81..f06d8a6a 100644
--- a/chapter22/src/test/java/com/seaofnodes/simple/Chapter19Test.java
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter19Test.java
@@ -271,6 +271,7 @@ for( int i=0; i<A#; i++ )
     A[i] = i;
 for( int i=0; i<A#; i++ )
     B[i] += A[i];
+return 0;
 """);
         code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
         assertEquals("return 0;", code.print());
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter21Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter21Test.java
index ea23728c..0e8c05fe 100644
--- a/chapter22/src/test/java/com/seaofnodes/simple/Chapter21Test.java
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter21Test.java
@@ -40,9 +40,9 @@ public class Chapter21Test {
 
     @Test public void testInfinite() {
         String src = "struct S { int i; }; S !s = new S; while(1) s.i++;";
-        testCPU(src,"x86_64_v2", "SystemV",0,"return Top;");
-        testCPU(src,"riscv"    , "SystemV",2,"return Top;");
-        testCPU(src,"arm"      , "SystemV",2,"return Top;");
+        testCPU(src,"x86_64_v2", "SystemV",0,"Stop[ ]");
+        testCPU(src,"riscv"    , "SystemV",0,"Stop[ ]");
+        testCPU(src,"arm"      , "SystemV",0,"Stop[ ]");
     }
 
     @Test
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter22Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter22Test.java
index 6bec499e..1dc6db5b 100644
--- a/chapter22/src/test/java/com/seaofnodes/simple/Chapter22Test.java
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter22Test.java
@@ -28,7 +28,7 @@ public class Chapter22Test {
             assertEquals(stop, code._stop.toString());
     }
 
-    @Test @Ignore
+    @Test
     public void testCoRecur() {
         String src = """
 struct A { B? b; C? c; i64 ax; val az = x*2; };
@@ -48,6 +48,11 @@ return cc.cz;
         assertEquals("25", Eval2.eval(code, 0));
     }
 
+    @Test @Ignore
+    public void testNo() {
+        String src = "val foo = { int arg -> 3; };";
+        CodeGen code = new CodeGen(src).parse().opto().typeCheck();
+    }
 
     @Test @Ignore
     public void testHelloWorld() throws IOException {
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Eval2.java b/chapter22/src/test/java/com/seaofnodes/simple/Eval2.java
index ecea97dd..03221325 100644
--- a/chapter22/src/test/java/com/seaofnodes/simple/Eval2.java
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Eval2.java
@@ -114,6 +114,7 @@ public abstract class Eval2 {
 
     public static String eval( CodeGen code, long arg ) { return eval(code,arg,1000); }
     public static String eval( CodeGen code, long arg, int timeout ) {
+        if( code._start.uctrl()==null ) return ""; // The empty program
         SB trace = null; // new SB(); // TRACE, set to null for off, new SB() for on
         // Force local scheduling phase
         if( code._phase.ordinal() < CodeGen.Phase.TypeCheck .ordinal() )  code.typeCheck();