Allocate space for siLatestTrackedScopes on demand

By the time siLatestTrackedScopes is needed the number of tracked variables is known so we can allocate an array of suitable size. Defaulting to lclMAX_TRACKED requires 4 kbytes and for many small methods that's a waste.

diff --git a/src/jit/codegen.h b/src/jit/codegen.h
index 755859ad0bc9246bdda27e158c67bda5e31cbba4..ef2094347ef0e239660016ebc1a6047fadee01ac 100644 (file)
--- a/src/jit/codegen.h
+++ b/src/jit/codegen.h
@@ -626,7 +626,7 @@ protected:
 
     // Tracks the last entry for each tracked register variable
 
-    siScope* siLatestTrackedScopes[lclMAX_TRACKED];
+    siScope** siLatestTrackedScopes;
 
     IL_OFFSET siLastEndOffs; // IL offset of the (exclusive) end of the last block processed
 

diff --git a/src/jit/scopeinfo.cpp b/src/jit/scopeinfo.cpp
index 366a060d54b8b18d9d6b4f74b466ecf2dc971a7f..41c343548f67d4adbd5b1e32298254d677087870 100644 (file)
--- a/src/jit/scopeinfo.cpp
+++ b/src/jit/scopeinfo.cpp
@@ -377,19 +377,33 @@ void CodeGen::siInit()
 
     if (compiler->info.compVarScopesCount == 0)
     {
-        return;
+        siLatestTrackedScopes = nullptr;
     }
-
+    else
+    {
 #if FEATURE_EH_FUNCLETS
-    siInFuncletRegion = false;
+        siInFuncletRegion = false;
 #endif // FEATURE_EH_FUNCLETS
 
-    for (unsigned i = 0; i < lclMAX_TRACKED; i++)
-    {
-        siLatestTrackedScopes[i] = nullptr;
-    }
+        unsigned scopeCount = compiler->lvaTrackedCount;
 
-    compiler->compResetScopeLists();
+        if (scopeCount == 0)
+        {
+            siLatestTrackedScopes = nullptr;
+        }
+        else
+        {
+            siLatestTrackedScopes =
+                static_cast<siScope**>(compiler->compGetMemArray(scopeCount, sizeof(siScope*), CMK_SiScope));
+
+            for (unsigned i = 0; i < scopeCount; i++)
+            {
+                siLatestTrackedScopes[i] = nullptr;
+            }
+        }
+
+        compiler->compResetScopeLists();
+    }
 }
 
 /*****************************************************************************
@@ -669,8 +683,6 @@ void CodeGen::siUpdate()
         LclVarDsc* lclVar = &compiler->lvaTable[lclNum];
         assert(lclVar->lvTracked);
 #endif
-
-        siScope* scope = siLatestTrackedScopes[varIndex];
         siEndTrackedScope(varIndex);
     }