Improve emitter output for IG creation/saving and other improvements (#80151)

1. When outputting IG information, be explicit if the IG is being created
or saved. Previously, it was harder to understand in a JitDump when an
"IGxx" line showed up, and was somewhat confusing when one showed up
after a new label BB started being generated that was actually saving the
previous, pre-BB code.
2. Use the standard `emitDispIG()` function to display an IG, in more places.
3. Move the `Mapped BBxx to IGyy` output to a more appropriate location (when
code from that BB has actually been generated into that IG -- which can happen
for multiple BBs).
4. Fix `refCntWtd2str()` to work better for non-aligned cases. This function
tries to generate a string like "8" with 3 trailing spaces so it will line up
with the "1" in "1.50" in aligned output (instead of generating something like
"8.00" which is more cluttered). But that's annoying when using the function for
non-aligned cases.
5. Fixed a wrongly attributed memory allocation, for `igBlocks`

Author: BruceForstall

src/coreclr/jit/codegencommon.cpp

@@ -2019,7 +2019,7 @@ void CodeGen::genEmitMachineCode()
     if (verbose)
     {
         printf("*************** After end code gen, before unwindEmit()\n");
-        GetEmitter()->emitDispIGlist(true);
+        GetEmitter()->emitDispIGlist(/* displayInstructions */ true);
     }
 #else
     if (compiler->opts.disAsm)
@@ -6409,7 +6409,7 @@ void CodeGen::genGeneratePrologsAndEpilogs()
     if (verbose)
     {
         printf("*************** Before prolog / epilog generation\n");
-        GetEmitter()->emitDispIGlist(false);
+        GetEmitter()->emitDispIGlist(/* displayInstructions */ false);
     }
 #endif
 
@@ -6457,7 +6457,7 @@ void CodeGen::genGeneratePrologsAndEpilogs()
     if (verbose)
     {
         printf("*************** After prolog / epilog generation\n");
-        GetEmitter()->emitDispIGlist(false);
+        GetEmitter()->emitDispIGlist(/* displayInstructions */ false);
     }
 #endif
 }

src/coreclr/jit/compiler.hpp

@@ -741,7 +741,7 @@ inline double getR8LittleEndian(const BYTE* ptr)
 
 #ifdef DEBUG
 const char* genES2str(BitVecTraits* traits, EXPSET_TP set);
-const char* refCntWtd2str(weight_t refCntWtd);
+const char* refCntWtd2str(weight_t refCntWtd, bool padForDecimalPlaces = false);
 #endif
 
 /*

src/coreclr/jit/emit.cpp

@@ -685,6 +685,28 @@ void emitter::emitGenIG(insGroup* ig)
     emitCurIGfreeEndp = emitCurIGfreeBase + emitIGbuffSize;
 }
 
+/*****************************************************************************
+ *
+ *  Add a new IG to the current list, and get it ready to receive code.
+ */
+
+void emitter::emitNewIG()
+{
+    insGroup* ig = emitAllocAndLinkIG();
+
+    /* It's linked in. Now, set it up to accept code */
+
+    emitGenIG(ig);
+
+#ifdef DEBUG
+    if (emitComp->verbose)
+    {
+        printf("Created:\n      ");
+        emitDispIG(ig, nullptr, /* displayInstructions */ false, /* displayLocation */ false);
+    }
+#endif // DEBUG
+}
+
 /*****************************************************************************
  *
  *  Finish and save the current IG.
@@ -850,20 +872,17 @@ insGroup* emitter::emitSavIG(bool emitAdd)
 #ifdef DEBUG
     if (emitComp->opts.dspCode)
     {
-        printf("\n      %s:", emitLabelString(ig));
         if (emitComp->verbose)
         {
-            printf("        ; offs=%06XH, funclet=%02u, bbWeight=%s", ig->igOffs, ig->igFuncIdx,
-                   refCntWtd2str(ig->igWeight));
-            emitDispIGflags(ig->igFlags);
+            printf("Saved:\n      ");
+            emitDispIG(ig, nullptr, /* displayInstructions */ false, /* displayLocation */ false);
         }
         else
         {
-            printf("        ; funclet=%02u", ig->igFuncIdx);
+            printf("      %s:        ; funclet=%02u\n", emitLabelString(ig), ig->igFuncIdx);
         }
-        printf("\n");
     }
-#endif
+#endif // DEBUG
 
 #if FEATURE_LOOP_ALIGN
     // Did we have any align instructions in this group?
@@ -1580,6 +1599,8 @@ void* emitter::emitAllocAnyInstr(size_t sz, emitAttr opsz)
     {
         emitCurIG->igBlocks.push_back(emitComp->compCurBB);
         emitCurIG->lastGeneratedBlock = emitComp->compCurBB;
+
+        JITDUMP("Mapped " FMT_BB " to %s\n", emitComp->compCurBB->bbNum, emitLabelString(emitCurIG));
     }
 #endif // DEBUG
 
@@ -1902,7 +1923,7 @@ void emitter::emitCreatePlaceholderIG(insGroupPlaceholderType igType,
     if (emitComp->verbose)
     {
         printf("*************** After placeholder IG creation\n");
-        emitDispIGlist(false);
+        emitDispIGlist(/* displayInstructions */ false);
     }
 #endif
 }
@@ -2604,11 +2625,9 @@ void* emitter::emitAddLabel(VARSET_VALARG_TP GCvars,
 #endif // defined(FEATURE_EH_FUNCLETS) && defined(TARGET_ARM)
 
 #ifdef DEBUG
-    JITDUMP("Mapped " FMT_BB " to %s\n", block->bbNum, emitLabelString(emitCurIG));
-
     if (EMIT_GC_VERBOSE)
     {
-        printf("Label: IG%02u, GCvars=%s ", emitCurIG->igNum, VarSetOps::ToString(emitComp, GCvars));
+        printf("Label: %s, GCvars=%s ", emitLabelString(emitCurIG), VarSetOps::ToString(emitComp, GCvars));
         dumpConvertedVarSet(emitComp, GCvars);
         printf(", gcrefRegs=");
         printRegMaskInt(gcrefRegs);
@@ -3589,7 +3608,7 @@ void emitter::emitDispIGflags(unsigned flags)
     }
 }
 
-void emitter::emitDispIG(insGroup* ig, insGroup* igPrev, bool verbose)
+void emitter::emitDispIG(insGroup* ig, insGroup* igPrev, bool displayInstructions, bool displayLocation)
 {
     const int TEMP_BUFFER_LEN = 40;
     char      buff[TEMP_BUFFER_LEN];
@@ -3649,18 +3668,22 @@ void emitter::emitDispIG(insGroup* ig, insGroup* igPrev, bool verbose)
 
         emitDispIGflags(igPh->igFlags);
 
-        if (ig == emitCurIG)
+        if (displayLocation)
         {
-            printf(" <-- Current IG");
-        }
-        if (igPh == emitPlaceholderList)
-        {
-            printf(" <-- First placeholder");
-        }
-        if (igPh == emitPlaceholderLast)
-        {
-            printf(" <-- Last placeholder");
+            if (ig == emitCurIG)
+            {
+                printf(" <-- Current IG");
+            }
+            if (igPh == emitPlaceholderList)
+            {
+                printf(" <-- First placeholder");
+            }
+            if (igPh == emitPlaceholderLast)
+            {
+                printf(" <-- Last placeholder");
+            }
         }
+
         printf("\n");
 
         printf("%*s;   PrevGCVars=%s ", strlen(buff), "",
@@ -3698,9 +3721,12 @@ void emitter::emitDispIG(insGroup* ig, insGroup* igPrev, bool verbose)
             separator = ", ";
         }
 
+        printf("%sbbWeight=%s", separator, refCntWtd2str(ig->igWeight));
+        separator = ", ";
+
         if (emitComp->compCodeGenDone)
         {
-            printf("%sbbWeight=%s PerfScore %.2f", separator, refCntWtd2str(ig->igWeight), ig->igPerfScore);
+            printf("%sPerfScore %.2f", separator, ig->igPerfScore);
             separator = ", ";
         }
 
@@ -3746,17 +3772,21 @@ void emitter::emitDispIG(insGroup* ig, insGroup* igPrev, bool verbose)
 
         emitDispIGflags(ig->igFlags);
 
-        if (ig == emitCurIG)
+        if (displayLocation)
         {
-            printf(" <-- Current IG");
-        }
-        if (ig == emitPrologIG)
-        {
-            printf(" <-- Prolog IG");
+            if (ig == emitCurIG)
+            {
+                printf(" <-- Current IG");
+            }
+            if (ig == emitPrologIG)
+            {
+                printf(" <-- Prolog IG");
+            }
         }
+
         printf("\n");
 
-        if (verbose)
+        if (displayInstructions)
         {
             instrDesc*     id  = emitFirstInstrDesc(ig->igData);
             UNATIVE_OFFSET ofs = ig->igOffs;
@@ -3791,14 +3821,14 @@ void emitter::emitDispIG(insGroup* ig, insGroup* igPrev, bool verbose)
     }
 }
 
-void emitter::emitDispIGlist(bool verbose)
+void emitter::emitDispIGlist(bool displayInstructions)
 {
     insGroup* ig;
     insGroup* igPrev;
 
     for (igPrev = nullptr, ig = emitIGlist; ig; igPrev = ig, ig = ig->igNext)
     {
-        emitDispIG(ig, igPrev, verbose);
+        emitDispIG(ig, igPrev, displayInstructions);
     }
 }
 
@@ -4156,7 +4186,7 @@ void emitter::emitRemoveJumpToNextInst()
     if (EMIT_INSTLIST_VERBOSE)
     {
         JITDUMP("\nInstruction group list before unconditional jump to next instruction removal:\n\n");
-        emitDispIGlist(true);
+        emitDispIGlist(/* displayInstructions */ true);
     }
     if (EMITVERBOSE)
     {
@@ -4216,9 +4246,9 @@ void emitter::emitRemoveJumpToNextInst()
                     printf("   id: %u: ", id->idDebugOnlyInfo()->idNum);
                     emitDispIns(id, false, true, false, 0, nullptr, 0, jmpGroup);
                     printf("jump group:\n");
-                    emitDispIG(jmpGroup, nullptr, true);
+                    emitDispIG(jmpGroup, nullptr, /* displayInstructions */ true);
                     printf("target group:\n");
-                    emitDispIG(targetGroup, nullptr, false);
+                    emitDispIG(targetGroup, nullptr, /* displayInstructions */ false);
                     assert(jmp == id);
                 }
 
@@ -4311,7 +4341,7 @@ void emitter::emitRemoveJumpToNextInst()
         if (EMIT_INSTLIST_VERBOSE)
         {
             printf("\nInstruction group list after unconditional jump to next instruction removal:\n\n");
-            emitDispIGlist(false);
+            emitDispIGlist(/* displayInstructions */ false);
         }
         if (EMITVERBOSE)
         {
@@ -4350,7 +4380,7 @@ void emitter::emitJumpDistBind()
     if (EMIT_INSTLIST_VERBOSE)
     {
         printf("\nInstruction list before jump distance binding:\n\n");
-        emitDispIGlist(true);
+        emitDispIGlist(/* displayInstructions */ true);
     }
     if (EMITVERBOSE)
     {
@@ -5097,7 +5127,7 @@ void emitter::emitJumpDistBind()
     if (EMIT_INSTLIST_VERBOSE)
     {
         printf("\nLabels list after the jump dist binding:\n\n");
-        emitDispIGlist(false);
+        emitDispIGlist(/* displayInstructions */ false);
     }
 
     emitCheckIGoffsets();
@@ -6208,7 +6238,7 @@ unsigned emitter::emitEndCodeGen(Compiler* comp,
     if (EMIT_INSTLIST_VERBOSE)
     {
         printf("\nInstruction list before instruction issue:\n\n");
-        emitDispIGlist(true);
+        emitDispIGlist(/* displayInstructions */ true);
     }
 
     emitCheckIGoffsets();
@@ -7099,7 +7129,7 @@ unsigned emitter::emitEndCodeGen(Compiler* comp,
     if (EMIT_INSTLIST_VERBOSE)
     {
         printf("\nLabels list after the end of codegen:\n\n");
-        emitDispIGlist(false);
+        emitDispIGlist(/* displayInstructions */ false);
     }
 
     emitCheckIGoffsets();
@@ -9004,7 +9034,7 @@ void emitter::emitInitIG(insGroup* ig)
 #ifdef DEBUG
     ig->lastGeneratedBlock = nullptr;
     // Explicitly call init, since IGs don't actually have a constructor.
-    ig->igBlocks.jitstd::list<BasicBlock*>::init(emitComp->getAllocator(CMK_LoopOpt));
+    ig->igBlocks.jitstd::list<BasicBlock*>::init(emitComp->getAllocator(CMK_DebugOnly));
 #endif
 }
 

src/coreclr/jit/emit.h

@@ -1745,8 +1745,11 @@ class emitter
     void emitDispGCInfoDelta();
 
     void emitDispIGflags(unsigned flags);
-    void emitDispIG(insGroup* ig, insGroup* igPrev = nullptr, bool verbose = false);
-    void emitDispIGlist(bool verbose = false);
+    void emitDispIG(insGroup* ig,
+                    insGroup* igPrev              = nullptr,
+                    bool      displayInstructions = false,
+                    bool      displayLocation     = true);
+    void emitDispIGlist(bool displayInstructions = false);
     void emitDispGCinfo();
     void emitDispJumpList();
     void emitDispClsVar(CORINFO_FIELD_HANDLE fldHnd, ssize_t offs, bool reloc = false);
@@ -3355,20 +3358,6 @@ inline BYTE* emitter::emitCodeWithInstructionSize(BYTE* codePtrBefore, BYTE* new
     return newCodePointer;
 }
 
-/*****************************************************************************
- *
- *  Add a new IG to the current list, and get it ready to receive code.
- */
-
-inline void emitter::emitNewIG()
-{
-    insGroup* ig = emitAllocAndLinkIG();
-
-    /* It's linked in. Now, set it up to accept code */
-
-    emitGenIG(ig);
-}
-
 /*****************************************************************************/
 #endif // _EMIT_H_
 /*****************************************************************************/

src/coreclr/jit/fgdiagnostic.cpp

@@ -1916,7 +1916,7 @@ void Compiler::fgTableDispBasicBlock(BasicBlock* block, int ibcColWidth /* = 0 *
         }
         else // print weight in this format ddd.dd
         {
-            printf("%6s", refCntWtd2str(weight));
+            printf("%6s", refCntWtd2str(weight, /* padForDecimalPlaces */ true));
         }
     }
 

src/coreclr/jit/lclvars.cpp

@@ -3827,7 +3827,7 @@ void Compiler::lvaSortByRefCount()
 
         INDEBUG(if (verbose) { gtDispLclVar(tracked[varIndex]); })
         JITDUMP(" [%6s]: refCnt = %4u, refCntWtd = %6s\n", varTypeName(varDsc->TypeGet()), varDsc->lvRefCnt(),
-                refCntWtd2str(varDsc->lvRefCntWtd()));
+                refCntWtd2str(varDsc->lvRefCntWtd(), /* padForDecimalPlaces */ true));
     }
 
     JITDUMP("\n");
@@ -7652,7 +7652,8 @@ void Compiler::lvaDumpEntry(unsigned lclNum, FrameLayoutState curState, size_t r
             printf("    ]");
         }
 
-        printf(" (%3u,%*s)", varDsc->lvRefCnt(), (int)refCntWtdWidth, refCntWtd2str(varDsc->lvRefCntWtd()));
+        printf(" (%3u,%*s)", varDsc->lvRefCnt(), (int)refCntWtdWidth,
+               refCntWtd2str(varDsc->lvRefCntWtd(), /* padForDecimalPlaces */ true));
 
         printf(" %7s ", varTypeName(type));
         if (genTypeSize(type) == 0)
@@ -7913,7 +7914,7 @@ void Compiler::lvaTableDump(FrameLayoutState curState)
     {
         for (lclNum = 0, varDsc = lvaTable; lclNum < lvaCount; lclNum++, varDsc++)
         {
-            size_t width = strlen(refCntWtd2str(varDsc->lvRefCntWtd()));
+            size_t width = strlen(refCntWtd2str(varDsc->lvRefCntWtd(), /* padForDecimalPlaces */ true));
             if (width > refCntWtdWidth)
             {
                 refCntWtdWidth = width;

src/coreclr/jit/lsra.cpp

@@ -958,7 +958,7 @@ void LinearScan::setBlockSequence()
         const LsraBlockInfo& bi = blockInfo[block->bbNum];
 
         // Note that predBBNum isn't set yet.
-        JITDUMP(" (%6s)", refCntWtd2str(bi.weight));
+        JITDUMP(" (%6s)", refCntWtd2str(bi.weight, /* padForDecimalPlaces */ true));
 
         if (bi.hasCriticalInEdge)
         {

src/coreclr/jit/optimizer.cpp

@@ -7718,7 +7718,8 @@ void Compiler::optHoistLoopBlocks(unsigned loopNum, ArrayStack<BasicBlock*>* blo
         weight_t    blockWeight = block->getBBWeight(this);
 
         JITDUMP("\n    optHoistLoopBlocks " FMT_BB " (weight=%6s) of loop " FMT_LP " <" FMT_BB ".." FMT_BB ">\n",
-                block->bbNum, refCntWtd2str(blockWeight), loopNum, loopDsc->lpTop->bbNum, loopDsc->lpBottom->bbNum);
+                block->bbNum, refCntWtd2str(blockWeight, /* padForDecimalPlaces */ true), loopNum,
+                loopDsc->lpTop->bbNum, loopDsc->lpBottom->bbNum);
 
         if (blockWeight < (BB_UNITY_WEIGHT / 10))
         {