[vm] Get SP without using VM generated stubs.

TEST=ci
Change-Id: Ie976408ff3cf5691a59081b7b405abe43d7adcc3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/493165
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>

runtime/vm/compiler/stub_code_compiler_arm.cc

@@ -2973,12 +2973,6 @@ void StubCodeCompiler::GenerateSubtypeNTestCacheStub(Assembler* assembler,
       });
 }
 
-// Return the current stack pointer address, used to do stack alignment checks.
-void StubCodeCompiler::GenerateGetCStackPointerStub() {
-  __ mov(R0, Operand(SP));
-  __ Ret();
-}
-
 // Jump to a frame on the call stack.
 // LR: return address.
 // R0: program_counter.

runtime/vm/compiler/stub_code_compiler_arm64.cc

@@ -3353,11 +3353,6 @@ void StubCodeCompiler::GenerateSubtypeNTestCacheStub(Assembler* assembler,
       });
 }
 
-void StubCodeCompiler::GenerateGetCStackPointerStub() {
-  __ mov(R0, CSP);
-  __ ret();
-}
-
 // Jump to a frame on the call stack.
 // LR: return address.
 // R0: program_counter.

runtime/vm/compiler/stub_code_compiler_ia32.cc

@@ -2891,14 +2891,6 @@ void StubCodeCompiler::GenerateSubtypeNTestCacheStub(Assembler* assembler,
   __ ret();
 }
 
-// Return the current stack pointer address, used to do stack alignment checks.
-// TOS + 0: return address
-// Result in EAX.
-void StubCodeCompiler::GenerateGetCStackPointerStub() {
-  __ leal(EAX, Address(ESP, target::kWordSize));
-  __ ret();
-}
-
 // Jump to a frame on the call stack.
 // TOS + 0: return address
 // TOS + 1: program_counter

runtime/vm/compiler/stub_code_compiler_riscv.cc

@@ -2868,11 +2868,6 @@ void StubCodeCompiler::GenerateSubtypeNTestCacheStub(Assembler* assembler,
       });
 }
 
-void StubCodeCompiler::GenerateGetCStackPointerStub() {
-  __ mv(A0, SP);
-  __ ret();
-}
-
 // Jump to a frame on the call stack.
 // RA: return address.
 // A0: program_counter.

runtime/vm/compiler/stub_code_compiler_x64.cc

@@ -3315,15 +3315,6 @@ void StubCodeCompiler::GenerateSubtypeNTestCacheStub(Assembler* assembler,
       });
 }
 
-// Return the current stack pointer address, used to stack alignment
-// checks.
-// TOS + 0: return address
-// Result in RAX.
-void StubCodeCompiler::GenerateGetCStackPointerStub() {
-  __ leaq(RAX, Address(RSP, target::kWordSize));
-  __ ret();
-}
-
 // Jump to a frame on the call stack.
 // TOS + 0: return address
 // Arg1: program counter

runtime/vm/native_arguments.h

@@ -35,10 +35,8 @@ class Thread;
 #else
 #define CHECK_STACK_ALIGNMENT                                                  \
   {                                                                            \
-    uword (*func)() = reinterpret_cast<uword (*)()>(                           \
-        StubCode::GetCStackPointer().EntryPoint());                            \
-    uword current_sp = func();                                                 \
-    ASSERT(Utils::IsAligned(current_sp, OS::ActivationFrameAlignment()));      \
+    ASSERT(Utils::IsAligned(OSThread::GetCurrentStackPointer(),                \
+                            OS::ActivationFrameAlignment()));                  \
   }
 #endif
 

runtime/vm/os_thread.cc

@@ -140,9 +140,15 @@ void OSThread::SetName(const char* name) {
 DART_NOINLINE
 uword OSThread::GetCurrentStackPointer() {
 #ifdef _MSC_VER
-  return reinterpret_cast<uword>(_AddressOfReturnAddress());
+  return reinterpret_cast<uword>(_AddressOfReturnAddress()) + kWordSize;
 #elif __GNUC__
+#if defined(HOST_ARCH_RISCV32) || defined(HOST_ARCH_RISCV64)
+  // RISC-V has unusual choice of FP as SP at entry (i.e., DWARF CFA).
   return reinterpret_cast<uword>(__builtin_frame_address(0));
+#else
+  // Usually FP is address of saved FP, two slots from SP at entry.
+  return reinterpret_cast<uword>(__builtin_frame_address(0)) + 2 * kWordSize;
+#endif
 #else
 #error Unimplemented
 #endif

runtime/vm/stub_code_list.h

@@ -29,7 +29,6 @@ namespace dart {
 // List of stubs created in the VM isolate, these stubs are shared by different
 // isolates running in this dart process.
 #define VM_STUB_CODE_LIST(V)                                                   \
-  V(GetCStackPointer)                                                          \
   V(JumpToFrame)                                                               \
   V(RunExceptionHandler)                                                       \
   V(RunExceptionHandlerUnbox)                                                  \