JIT: Make GS cookie phase run on LIR and move it after async phase

src/coreclr/jit/compiler.cpp

@@ -4553,10 +4553,6 @@ void Compiler::compCompile(void** methodCodePtr, uint32_t* methodCodeSize, JitFl
     };
     DoPhase(this, PHASE_POST_MORPH, postMorphPhase);
 
-    // GS security checks for unsafe buffers
-    //
-    DoPhase(this, PHASE_GS_COOKIE, &Compiler::gsPhase);
-
     if (opts.OptimizationEnabled())
     {
         // Compute the block weights
@@ -4948,6 +4944,10 @@ void Compiler::compCompile(void** methodCodePtr, uint32_t* methodCodeSize, JitFl
         DoPhase(this, PHASE_ASYNC, &Compiler::TransformAsync);
     }
 
+    // GS security checks for unsafe buffers
+    //
+    DoPhase(this, PHASE_GS_COOKIE, &Compiler::gsPhase);
+
 #ifdef TARGET_WASM
     // Transform any strongly connected components into reducible flow.
     //

src/coreclr/jit/compiler.h

@@ -11247,18 +11247,23 @@ class Compiler
 #endif
     };
 
-    GSCookie*           gsGlobalSecurityCookieAddr; // Address of global cookie for unsafe buffer checks
-    GSCookie            gsGlobalSecurityCookieVal;  // Value of global cookie if addr is NULL
-    ShadowParamVarInfo* gsShadowVarInfo = nullptr;  // Table used by shadow param analysis code
+    GSCookie*           gsGlobalSecurityCookieAddr;     // Address of global cookie for unsafe buffer checks
+    GSCookie            gsGlobalSecurityCookieVal;      // Value of global cookie if addr is NULL
+    ShadowParamVarInfo* gsShadowVarInfo      = nullptr; // Table used by shadow param analysis code
+    unsigned            gsShadowVarInfoCount = 0;
 
     PhaseStatus gsPhase();
     void        gsGSChecksInitCookie();   // Grabs cookie variable
-    void        gsCopyShadowParams();     // Identify vulnerable params and create dhadow copies
+    void        gsCopyShadowParams();     // Identify vulnerable params and create shadow copies
     bool        gsFindVulnerableParams(); // Shadow param analysis code
-    void        gsParamsToShadows();      // Insert copy code and replave param uses by shadow
-
-    static fgWalkPreFn gsMarkPtrsAndAssignGroups; // Shadow param analysis tree-walk
-    static fgWalkPreFn gsReplaceShadowParams;     // Shadow param replacement tree-walk
+    template <typename TVisit>
+    void gsVisitDependentLocals(GenTree* tree, TVisit visit);
+    void gsMarkPointers(GenTree* tree);
+    void gsUnionAssignGroups(unsigned lclNum1, unsigned lclNum2, GenTree* reason);
+    void gsParamsToShadows(); // Insert copy code and replace param uses by shadow
+    void gsCopyIntoShadow(unsigned lclNum, unsigned shadowLclNum);
+    bool gsCreateShadowingLocals();
+    void gsRewriteTreeForShadowParam(GenTree* tree);
 
 #define DEFAULT_MAX_INLINE_SIZE                                                                                        \
     100 // Methods with >  DEFAULT_MAX_INLINE_SIZE IL bytes will never be inlined.