JIT: Dump BB in/out memory SSAs inline when SSA is valid (#95017)

When SSA is considered to be valid, write in and out SSA numbers for memory states when dumping the blocks. For example: ```csharp public static void Foo(C c) { if (c.V % 2 == 0) { c.V = 123; } else { c.V = 456; } Console.WriteLine(c.V); } public class C { public int V; } ``` dumps ``` ------------ BB01 [000..00A) -> BB03 (cond), preds={} succs={BB02,BB03} ByrefExposed, GcHeap = m:1 ***** BB01 STMT00000 ( 0x000[E-] ... 0x008 ) N009 ( 10, 10) [000007] ---XG------ ▌ JTRUE void N008 ( 8, 8) [000006] J--XG--N--- └──▌ NE int N006 ( 6, 6) [000004] ---XG------ ├──▌ AND int N004 ( 4, 4) [000002] ---XG------ │ ├──▌ IND int N003 ( 2, 2) [000024] -------N--- │ │ └──▌ ADD byref N001 ( 1, 1) [000000] ----------- │ │ ├──▌ LCL_VAR ref V00 arg0 u:1 N002 ( 1, 1) [000023] ----------- │ │ └──▌ CNS_INT long 8 Fseq[V] N005 ( 1, 1) [000003] ----------- │ └──▌ CNS_INT int 1 N007 ( 1, 1) [000005] ----------- └──▌ CNS_INT int 0 ByrefExposed, GcHeap = m:1 ------------ BB02 [00A..014) -> BB04 (always), preds={BB01} succs={BB04} ByrefExposed, GcHeap = m:1 ***** BB02 STMT00004 ( 0x00A[E-] ... 0x00D ) N005 ( 6, 6) [000020] -A-XG------ ▌ STOREIND int N003 ( 2, 2) [000028] -------N--- ├──▌ ADD byref N001 ( 1, 1) [000017] ----------- │ ├──▌ LCL_VAR ref V00 arg0 u:1 N002 ( 1, 1) [000027] ----------- │ └──▌ CNS_INT long 8 Fseq[V] N004 ( 1, 1) [000018] ----------- └──▌ CNS_INT int 123 ByrefExposed, GcHeap = m:5 ------------ BB03 [014..01F), preds={BB01} succs={BB04} ByrefExposed, GcHeap = m:1 ***** BB03 STMT00001 ( 0x014[E-] ... 0x01A ) N005 ( 6, 9) [000011] -A-XG------ ▌ STOREIND int N003 ( 2, 2) [000026] -------N--- ├──▌ ADD byref N001 ( 1, 1) [000008] ----------- │ ├──▌ LCL_VAR ref V00 arg0 u:1 N002 ( 1, 1) [000025] ----------- │ └──▌ CNS_INT long 8 Fseq[V] N004 ( 1, 4) [000009] ----------- └──▌ CNS_INT int 456 ByrefExposed, GcHeap = m:4 ------------ BB04 [01F..02B) (return), preds={BB02,BB03} succs={} ByrefExposed, GcHeap = phi(m:5, m:4) ***** BB04 STMT00002 ( 0x01F[E-] ... 0x02A ) N005 ( 18, 10) [000015] --CXG------ ▌ CALL void System.Console:WriteLine(int) N004 ( 4, 4) [000014] ---XG------ arg0 in rcx └──▌ IND int N003 ( 2, 2) [000030] -------N--- └──▌ ADD byref N001 ( 1, 1) [000012] ----------- ├──▌ LCL_VAR ref V00 arg0 u:1 (last use) N002 ( 1, 1) [000029] ----------- └──▌ CNS_INT long 8 Fseq[V] ***** BB04 STMT00003 ( 0x02A[E-] ... ??? ) N001 ( 0, 0) [000016] ----------- ▌ RETURN void ByrefExposed, GcHeap = m:3 ``` after SSA.
dotnet · Nov 21, 2023 · 186cf81 · 186cf81
1 parent aaa5347
commit 186cf81
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Showing 4 changed files with 94 additions and 8 deletions.
diff --git a/src/coreclr/jit/compiler.cpp b/src/coreclr/jit/compiler.cpp
@@ -1965,7 +1965,7 @@ void Compiler::compInit(ArenaAllocator*       pAlloc,
     m_nodeToLoopMemoryBlockMap = nullptr;
     m_signatureToLookupInfoMap = nullptr;
     fgSsaPassesCompleted       = 0;
-    fgSsaChecksEnabled         = false;
+    fgSsaValid                 = false;
     fgVNPassesCompleted        = 0;
 
     // check that HelperCallProperties are initialized
@@ -4960,10 +4960,10 @@ void Compiler::compCompile(void** methodCodePtr, uint32_t* methodCodeSize, JitFl
             //
             // So, disable the ssa checks.
             //
-            if (fgSsaChecksEnabled)
+            if (fgSsaValid)
             {
-                JITDUMP("Disabling SSA checking before assertion prop\n");
-                fgSsaChecksEnabled = false;
+                JITDUMP("Marking SSA as invalid before assertion prop\n");
+                fgSsaValid = false;
             }
 
             if (doAssertionProp)
@@ -5742,7 +5742,7 @@ void Compiler::ResetOptAnnotations()
     m_dominancePreds     = nullptr;
     fgSsaPassesCompleted = 0;
     fgVNPassesCompleted  = 0;
-    fgSsaChecksEnabled   = false;
+    fgSsaValid           = false;
 
     for (BasicBlock* const block : Blocks())
     {

diff --git a/src/coreclr/jit/compiler.h b/src/coreclr/jit/compiler.h
@@ -5051,7 +5051,7 @@ class Compiler
     void fgResetForSsa();
 
     unsigned fgSsaPassesCompleted; // Number of times fgSsaBuild has been run.
-    bool     fgSsaChecksEnabled;   // True if SSA info can be cross-checked versus IR
+    bool     fgSsaValid;           // True if SSA info is valid and can be cross-checked versus IR
 
 #ifdef DEBUG
     void DumpSsaSummary();
@@ -5655,6 +5655,9 @@ class Compiler
     void fgDumpBlock(BasicBlock* block);
     void fgDumpTrees(BasicBlock* firstBlock, BasicBlock* lastBlock);
 
+    void fgDumpBlockMemorySsaIn(BasicBlock* block);
+    void fgDumpBlockMemorySsaOut(BasicBlock* block);
+
     static fgWalkPreFn fgStress64RsltMulCB;
     void               fgStress64RsltMul();
     void               fgDebugCheckUpdate();

diff --git a/src/coreclr/jit/fgdiagnostic.cpp b/src/coreclr/jit/fgdiagnostic.cpp
@@ -2461,6 +2461,11 @@ void Compiler::fgDumpBlock(BasicBlock* block)
     printf("\n------------ ");
     block->dspBlockHeader(this);
 
+    if (fgSsaValid)
+    {
+        fgDumpBlockMemorySsaIn(block);
+    }
+
     if (!block->IsLIR())
     {
         for (Statement* const stmt : block->Statements())
@@ -2472,6 +2477,12 @@ void Compiler::fgDumpBlock(BasicBlock* block)
     {
         gtDispRange(LIR::AsRange(block));
     }
+
+    if (fgSsaValid)
+    {
+        printf("\n");
+        fgDumpBlockMemorySsaOut(block);
+    }
 }
 
 //------------------------------------------------------------------------
@@ -2498,6 +2509,78 @@ void Compiler::fgDumpTrees(BasicBlock* firstBlock, BasicBlock* lastBlock)
            "----------\n");
 }
 
+//------------------------------------------------------------------------
+// fgDumpBlockMemorySsaIn: Dump memory state SSAs incoming to a block.
+//
+// Arguments:
+//    block - The block
+//
+void Compiler::fgDumpBlockMemorySsaIn(BasicBlock* block)
+{
+    for (MemoryKind memoryKind : allMemoryKinds())
+    {
+        if (byrefStatesMatchGcHeapStates)
+        {
+            printf("SSA MEM: %s, %s", memoryKindNames[ByrefExposed], memoryKindNames[GcHeap]);
+        }
+        else
+        {
+            printf("SSA MEM: %s", memoryKindNames[memoryKind]);
+        }
+
+        if (block->bbMemorySsaPhiFunc[memoryKind] == nullptr)
+        {
+            printf(" = m:%u\n", block->bbMemorySsaNumIn[memoryKind]);
+        }
+        else
+        {
+            printf(" = phi(");
+            BasicBlock::MemoryPhiArg* phiArgs = block->bbMemorySsaPhiFunc[memoryKind];
+            const char*               sep     = "";
+            for (BasicBlock::MemoryPhiArg* arg = block->bbMemorySsaPhiFunc[memoryKind]; arg != nullptr;
+                 arg                           = arg->m_nextArg)
+            {
+                printf("%sm:%u", sep, arg->GetSsaNum());
+                sep = ", ";
+            }
+            printf(")\n");
+        }
+
+        if (byrefStatesMatchGcHeapStates)
+        {
+            break;
+        }
+    }
+}
+
+//------------------------------------------------------------------------
+// fgDumpBlockMemorySsaOut: Dump memory state SSAs outgoing from a block.
+//
+// Arguments:
+//    block - The block
+//
+void Compiler::fgDumpBlockMemorySsaOut(BasicBlock* block)
+{
+    for (MemoryKind memoryKind : allMemoryKinds())
+    {
+        if (byrefStatesMatchGcHeapStates)
+        {
+            printf("SSA MEM: %s, %s", memoryKindNames[ByrefExposed], memoryKindNames[GcHeap]);
+        }
+        else
+        {
+            printf("SSA MEM: %s", memoryKindNames[memoryKind]);
+        }
+
+        printf(" = m:%u\n", block->bbMemorySsaNumOut[memoryKind]);
+
+        if (byrefStatesMatchGcHeapStates)
+        {
+            break;
+        }
+    }
+}
+
 /*****************************************************************************
  * Try to create as many candidates for GTF_MUL_64RSLT as possible.
  * We convert 'intOp1*intOp2' into 'int(long(nop(intOp1))*long(intOp2))'.
@@ -4525,7 +4608,7 @@ class SsaCheckVisitor : public GenTreeVisitor<SsaCheckVisitor>
 //
 void Compiler::fgDebugCheckSsa()
 {
-    if (!fgSsaChecksEnabled)
+    if (!fgSsaValid)
     {
         return;
     }

diff --git a/src/coreclr/jit/ssabuilder.cpp b/src/coreclr/jit/ssabuilder.cpp
@@ -64,7 +64,7 @@ PhaseStatus Compiler::fgSsaBuild()
     SsaBuilder builder(this);
     builder.Build();
     fgSsaPassesCompleted++;
-    fgSsaChecksEnabled = true;
+    fgSsaValid = true;
 #ifdef DEBUG
     JitTestCheckSSA();
 #endif // DEBUG