From b9b1d3e5dfd5de944419f4f3b2df429cbacab978 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <nnethercote@mozilla.com>
Date: Mon, 24 Aug 2009 08:57:40 +1000
Subject: [PATCH] Bug 511329 - nanojit: don't print dead LIR instructions with
 TMFLAGS=assembly. r=edwsmith.

---
 js/src/nanojit/Assembler.cpp | 80 +++++++++++++-------------------------------
 1 file changed, 23 insertions(+), 57 deletions(-)

diff --git a/js/src/nanojit/Assembler.cpp b/js/src/nanojit/Assembler.cpp
index a95b35f6b9..08ce77e6c1 100644
--- a/js/src/nanojit/Assembler.cpp
+++ b/js/src/nanojit/Assembler.cpp
@@ -48,56 +48,6 @@
 namespace nanojit
 {
 #ifdef NJ_VERBOSE
-    class VerboseBlockReader: public LirFilter
-    {
-        Assembler *assm;
-        LirNameMap *names;
-        InsList block;
-        bool flushnext;
-    public:
-        VerboseBlockReader(Allocator& alloc, LirFilter *in, Assembler *a, LirNameMap *n)
-            : LirFilter(in), assm(a), names(n), block(alloc), flushnext(false)
-        {}
-
-        void flush() {
-            flushnext = false;
-            if (!block.isEmpty()) {
-                for (Seq<LIns*>* p = block.get(); p != NULL; p = p->tail)
-                    assm->outputf("    %s", names->formatIns(p->head));
-                block.clear();
-            }
-        }
-
-        void flush_add(LInsp i) {
-            flush();
-            block.add(i);
-        }
-
-        LInsp read() {
-            LInsp i = in->read();
-            if (i->isop(LIR_start)) {
-                flush();
-                return i;
-            }
-            if (i->isGuard()) {
-                flush_add(i);
-                if (i->oprnd1())
-                    block.add(i->oprnd1());
-            }
-            else if (i->isRet() || i->isBranch()) {
-                flush_add(i);
-            }
-            else {
-                if (flushnext)
-                    flush();
-                block.add(i);//flush_add(i);
-                if (i->isop(LIR_label))
-                    flushnext = true;
-            }
-            return i;
-        }
-    };
-
     /* A listing filter for LIR, going through backwards.  It merely
        passes its input to its output, but notes it down too.  When
        destructed, prints out what went through.  Is intended to be
@@ -728,13 +678,6 @@ namespace nanojit
         prev = pp_after_sf2;
         })
 
-        // end of pipeline
-        verbose_only(
-        VerboseBlockReader vbr(alloc, prev, this, frag->lirbuf->names);
-        if (_logc->lcbits & LC_Assembly)
-            prev = &vbr;
-        )
-
         _inExit = false;
 
         LabelStateMap labels(alloc);
@@ -1363,6 +1306,29 @@ namespace nanojit
                 }
             }
 
+            // We have to do final LIR printing inside this loop.  If we do it
+            // before this loop, we we end up printing a lot of dead LIR
+            // instructions.
+            //
+            // We print the LIns after generating the code.  This ensures that
+            // the LIns will appear in debug output *before* the generated
+            // code, because Assembler::outputf() prints everything in reverse.
+            //
+            // Note that some live LIR instructions won't be printed.  Eg. an
+            // immediate won't be printed unless it is explicitly loaded into
+            // a register (as opposed to being incorporated into an immediate
+            // field in another machine instruction).
+            //
+            if (_logc->lcbits & LC_Assembly) {
+                outputf("    %s", _thisfrag->lirbuf->names->formatIns(ins));
+                // Special case: a guard condition won't get printed next time
+                // around the loop, so do it now.
+                if (ins->isGuard() && ins->oprnd1()) {
+                    outputf("    %s       # handled by the guard",
+                            _thisfrag->lirbuf->names->formatIns(ins->oprnd1()));
+                }
+            }
+
             if (error())
                 return;
 
-- 
2.11.4.GIT