From a9c039689e0d08ecc68783649871e9c0090ce8c3 Mon Sep 17 00:00:00 2001
From: Bruce Forstall <brucefo@microsoft.com>
Date: Fri, 12 Apr 2019 13:19:14 -0700
Subject: [PATCH] Display the arm instruction size

When dumping an arm instruction, and when we don't have the actual
code bytes (such as during code generation, as opposed to emission),
display the (current) instruction size, either 2 bytes (2B),
4 bytes (4B), or 6 bytes (6B).
---
 src/jit/emit.h        |  2 +-
 src/jit/emitarm.cpp   | 25 +++++++++++++++++++++++--
 src/jit/emitarm64.cpp |  5 +++--
 src/jit/emitxarch.cpp |  4 ++--
 4 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/src/jit/emit.h b/src/jit/emit.h
index 1308531..b429920 100644
--- a/src/jit/emit.h
+++ b/src/jit/emit.h
@@ -1374,7 +1374,7 @@ protected:
     void emitDispClsVar(CORINFO_FIELD_HANDLE fldHnd, ssize_t offs, bool reloc = false);
     void emitDispFrameRef(int varx, int disp, int offs, bool asmfm);
     void emitDispInsOffs(unsigned offs, bool doffs);
-    void emitDispInsHex(BYTE* code, size_t sz);
+    void emitDispInsHex(instrDesc* id, BYTE* code, size_t sz);
 
 #else // !DEBUG
 #define emitVarRefOffs 0
diff --git a/src/jit/emitarm.cpp b/src/jit/emitarm.cpp
index 3d7089b..9e36efb 100644
--- a/src/jit/emitarm.cpp
+++ b/src/jit/emitarm.cpp
@@ -6778,7 +6778,7 @@ void emitter::emitDispGC(emitAttr attr)
  *  Display (optionally) the instruction encoding in hex
  */
 
-void emitter::emitDispInsHex(BYTE* code, size_t sz)
+void emitter::emitDispInsHex(instrDesc* id, BYTE* code, size_t sz)
 {
     // We do not display the instruction hex if we want diff-able disassembly
     if (!emitComp->opts.disDiffable)
@@ -6791,6 +6791,27 @@ void emitter::emitDispInsHex(BYTE* code, size_t sz)
         {
             printf("  %04X %04X", (*((unsigned short*)(code + 0))), (*((unsigned short*)(code + 2))));
         }
+        else
+        {
+            assert(sz == 0);
+
+            // At least display the encoding size of the instruction, even if not displaying its actual encoding.
+            insSize isz = emitInsSize(id->idInsFmt());
+            switch (isz)
+            {
+                case ISZ_16BIT:
+                    printf("  2B");
+                    break;
+                case ISZ_32BIT:
+                    printf("  4B");
+                    break;
+                case ISZ_48BIT:
+                    printf("  6B");
+                    break;
+                default:
+                    unreached();
+            }
+        }
     }
 }
 
@@ -6822,7 +6843,7 @@ void emitter::emitDispInsHelp(
 
     /* Display the instruction hex code */
 
-    emitDispInsHex(code, sz);
+    emitDispInsHex(id, code, sz);
 
     printf("      ");
 
diff --git a/src/jit/emitarm64.cpp b/src/jit/emitarm64.cpp
index afd5cf4..0345a36 100644
--- a/src/jit/emitarm64.cpp
+++ b/src/jit/emitarm64.cpp
@@ -10698,7 +10698,7 @@ void emitter::emitDispAddrRRExt(regNumber reg1, regNumber reg2, insOpts opt, boo
  *  Display (optionally) the instruction encoding in hex
  */
 
-void emitter::emitDispInsHex(BYTE* code, size_t sz)
+void emitter::emitDispInsHex(instrDesc* id, BYTE* code, size_t sz)
 {
     // We do not display the instruction hex if we want diff-able disassembly
     if (!emitComp->opts.disDiffable)
@@ -10709,6 +10709,7 @@ void emitter::emitDispInsHex(BYTE* code, size_t sz)
         }
         else
         {
+            assert(sz == 0);
             printf("              ");
         }
     }
@@ -10742,7 +10743,7 @@ void emitter::emitDispIns(
 
     /* Display the instruction hex code */
 
-    emitDispInsHex(pCode, sz);
+    emitDispInsHex(id, pCode, sz);
 
     printf("      ");
 
diff --git a/src/jit/emitxarch.cpp b/src/jit/emitxarch.cpp
index 6052b97..f7b3c5b 100644
--- a/src/jit/emitxarch.cpp
+++ b/src/jit/emitxarch.cpp
@@ -8049,7 +8049,7 @@ void emitter::emitDispShift(instruction ins, int cnt)
  *  Display (optionally) the bytes for the instruction encoding in hex
  */
 
-void emitter::emitDispInsHex(BYTE* code, size_t sz)
+void emitter::emitDispInsHex(instrDesc* id, BYTE* code, size_t sz)
 {
     // We do not display the instruction hex if we want diff-able disassembly
     if (!emitComp->opts.disDiffable)
@@ -8216,7 +8216,7 @@ void emitter::emitDispIns(
     {
         /* Display the instruction hex code */
 
-        emitDispInsHex(code, sz);
+        emitDispInsHex(id, code, sz);
     }
 
     /* Display the instruction name */
-- 
2.7.4