Introduce DOTNET_JITAllowOptionalRelocs (#88008)

Author: EgorBo

src/coreclr/inc/clrconfigvalues.h

@@ -310,6 +310,7 @@ CONFIG_DWORD_INFO(INTERNAL_JitGCStress, W("JitGCStress"), 0, "GC stress mode for
 CONFIG_DWORD_INFO(INTERNAL_JitHeartbeat, W("JitHeartbeat"), 0, "")
 CONFIG_DWORD_INFO(INTERNAL_JitHelperLogging, W("JitHelperLogging"), 0, "")
 RETAIL_CONFIG_DWORD_INFO(UNSUPPORTED_JITMinOpts, W("JITMinOpts"), 0, "Forces MinOpts")
+RETAIL_CONFIG_DWORD_INFO(UNSUPPORTED_JITAllowOptionalRelocs, W("JITAllowOptionalRelocs"), 1, "Allow optional relocs")
 RETAIL_CONFIG_STRING_INFO(EXTERNAL_JitName, W("JitName"), "Primary jit to use")
 CONFIG_STRING_INFO(INTERNAL_JitPath, W("JitPath"), "Full path to primary jit to use")
 #if defined(ALLOW_SXS_JIT)

src/coreclr/vm/eeconfig.cpp

@@ -111,6 +111,7 @@ HRESULT EEConfig::Init()
     iJitOptimizeType = OPT_DEFAULT;
     fJitFramed = false;
     fJitMinOpts = false;
+    fJitAllowOptionalRelocs = false;
     fPInvokeRestoreEsp = (DWORD)-1;
 
     fNgenBindOptimizeNonGac = false;
@@ -543,6 +544,7 @@ HRESULT EEConfig::sync()
 
     fJitFramed = (CLRConfig::GetConfigValue(CLRConfig::UNSUPPORTED_JitFramed) != 0);
     fJitMinOpts = (CLRConfig::GetConfigValue(CLRConfig::UNSUPPORTED_JITMinOpts) == 1);
+    fJitAllowOptionalRelocs = (CLRConfig::GetConfigValue(CLRConfig::UNSUPPORTED_JITAllowOptionalRelocs) == 1);
     iJitOptimizeType      =  CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_JitOptimizeType);
     if (iJitOptimizeType > OPT_RANDOM)     iJitOptimizeType = OPT_DEFAULT;
 

src/coreclr/vm/eeconfig.h

@@ -76,6 +76,7 @@ class EEConfig
     unsigned int  GenOptimizeType(void)                     const {LIMITED_METHOD_CONTRACT;  return iJitOptimizeType; }
     bool          JitFramed(void)                           const {LIMITED_METHOD_CONTRACT;  return fJitFramed; }
     bool          JitMinOpts(void)                          const {LIMITED_METHOD_CONTRACT;  return fJitMinOpts; }
+    bool          JitAllowOptionalRelocs(void)              const {LIMITED_METHOD_CONTRACT;  return fJitAllowOptionalRelocs; }
 
     // Tiered Compilation config
 #if defined(FEATURE_TIERED_COMPILATION)
@@ -478,6 +479,7 @@ class EEConfig
     bool fTrackDynamicMethodDebugInfo; //  Enable/Disable tracking dynamic method debug info
     bool fJitFramed;                   // Enable/Disable EBP based frames
     bool fJitMinOpts;                  // Enable MinOpts for all jitted methods
+    bool fJitAllowOptionalRelocs;      // Allow optional relocs
 
     unsigned iJitOptimizeType; // 0=Blended,1=SmallCode,2=FastCode,              default is 0=Blended
 

src/coreclr/vm/jitinterface.cpp

@@ -12666,7 +12666,7 @@ PCODE UnsafeJitFunction(PrepareCodeConfig* config,
 #endif
 
 #if defined(TARGET_AMD64)
-    BOOL fAllowRel32 = (g_fAllowRel32 | fForceJumpStubOverflow);
+    BOOL fAllowRel32 = (g_fAllowRel32 | fForceJumpStubOverflow) && g_pConfig->JitAllowOptionalRelocs();
 #endif
 
     size_t reserveForJumpStubs = 0;