Fix#16827 Stack probing for Linux

src/jit/codegencommon.cpp

@@ -6325,7 +6325,9 @@ void CodeGen::genAllocLclFrame(unsigned frameSize, regNumber initReg, bool* pIni
         }
 #endif // !_TARGET_XARCH_
 
+#if CPU_LOAD_STORE_ARCH || !defined(_TARGET_UNIX_)
         instGen_Set_Reg_To_Zero(EA_PTRSIZE, initReg);
+#endif
 
         //
         // Can't have a label inside the ReJIT padding area
@@ -6381,6 +6383,7 @@ void CodeGen::genAllocLclFrame(unsigned frameSize, regNumber initReg, bool* pIni
 
 #else // !CPU_LOAD_STORE_ARCH
 
+#ifndef _TARGET_UNIX_
         // Code size for each instruction. We need this because the
         // backward branch is hard-coded with the number of bytes to branch.
         // The encoding differs based on the architecture and what register is
@@ -6419,6 +6422,60 @@ void CodeGen::genAllocLclFrame(unsigned frameSize, regNumber initReg, bool* pIni
 #endif // !_TARGET_AMD64_
 
         inst_IV(INS_jge, bytesForBackwardJump); // Branch backwards to start of loop
+#else  // _TARGET_UNIX_
+        // Code size for each instruction. We need this because the
+        // backward branch is hard-coded with the number of bytes to branch.
+        // The encoding differs based on the architecture and what register is
+        // used (namely, using RAX has a smaller encoding).
+        //
+        // For x86
+        //      lea eax, [esp - frameSize]
+        // loop:
+        //      lea esp, [esp - pageSize]   7
+        //      test [esp], eax             3
+        //      cmp esp, eax                2
+        //      jge loop                    2
+        //      lea rsp, [rbp + frameSize]
+        //
+        // For AMD64 using RAX
+        //      lea rax, [rsp - frameSize]
+        // loop:
+        //      lea rsp, [rsp - pageSize]   8
+        //      test [rsp], rax             4
+        //      cmp rsp, rax                3
+        //      jge loop                    2
+        //      lea rsp, [rax + frameSize]
+        //
+        // For AMD64 using RBP
+        //      lea rbp, [rsp - frameSize]
+        // loop:
+        //      lea rsp, [rsp - pageSize]   8
+        //      test [rsp], rbp             4
+        //      cmp rsp, rbp                3
+        //      jge loop                    2
+        //      lea rsp, [rbp + frameSize]
+
+        int sPageSize = (int)pageSize;
+
+        getEmitter()->emitIns_R_AR(INS_lea, EA_PTRSIZE, initReg, REG_SPBASE, -((ssize_t)frameSize)); // get frame border
+
+        getEmitter()->emitIns_R_AR(INS_lea, EA_PTRSIZE, REG_SPBASE, REG_SPBASE, -sPageSize);
+        getEmitter()->emitIns_R_AR(INS_TEST, EA_PTRSIZE, initReg, REG_SPBASE, 0);
+        inst_RV_RV(INS_cmp, REG_SPBASE, initReg);
+
+        int bytesForBackwardJump;
+#ifdef _TARGET_AMD64_
+        assert((initReg == REG_EAX) || (initReg == REG_EBP)); // We use RBP as initReg for EH funclets.
+        bytesForBackwardJump = -17;
+#else  // !_TARGET_AMD64_
+        assert(initReg == REG_EAX);
+        bytesForBackwardJump = -14;
+#endif // !_TARGET_AMD64_
+
+        inst_IV(INS_jge, bytesForBackwardJump); // Branch backwards to start of loop
+
+        getEmitter()->emitIns_R_AR(INS_lea, EA_PTRSIZE, REG_SPBASE, initReg, frameSize); // restore stack pointer
+#endif // _TARGET_UNIX_
 
 #endif // !CPU_LOAD_STORE_ARCH