[liftoff][arm] Add explicit stack check for large frames

Handle large frames by doing an explicit check to see if there is enough
remaining stack space before the stack limit.
The bailout which can be removed then is being triggered on more than 1
percent of all functions, so this is expected to improve compile time by
several percent, because we avoid the costly TurboFan compilation for
those >1%.

R=ahaas@chromium.org

Bug: v8:11235
Change-Id: I935998f7676647572598b52c989f7d41cc5239a8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3046180
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75897}

src/wasm/baseline/arm/liftoff-assembler-arm.h

@@ -10,6 +10,7 @@
 #include "src/heap/memory-chunk.h"
 #include "src/wasm/baseline/liftoff-assembler.h"
 #include "src/wasm/baseline/liftoff-register.h"
+#include "src/wasm/wasm-objects.h"
 
 namespace v8 {
 namespace internal {
@@ -478,51 +479,78 @@ void LiftoffAssembler::PrepareTailCall(int num_callee_stack_params,
 
 void LiftoffAssembler::AlignFrameSize() {}
 
-void LiftoffAssembler::PatchPrepareStackFrame(int offset) {
+void LiftoffAssembler::PatchPrepareStackFrame(
+    int offset, SafepointTableBuilder* safepoint_table_builder) {
   // The frame_size includes the frame marker. The frame marker has already been
   // pushed on the stack though, so we don't need to allocate memory for it
   // anymore.
   int frame_size = GetTotalFrameSize() - kSystemPointerSize;
 
-  // When using the simulator, deal with Liftoff which allocates the stack
-  // before checking it.
-  // TODO(arm): Remove this when the stack check mechanism will be updated.
-  // Note: This check is only needed for simulator runs, but we run it
-  // unconditionally to make sure that the simulator executes the same code
-  // that's also executed on native hardware (see https://crbug.com/v8/11041).
-  if (frame_size > KB / 2) {
-    bailout(kOtherReason,
-            "Stack limited to 512 bytes to avoid a bug in StackCheck");
-    return;
-  }
-
   PatchingAssembler patching_assembler(AssemblerOptions{},
                                        buffer_start_ + offset,
                                        liftoff::kPatchInstructionsRequired);
-#if V8_OS_WIN
-  if (frame_size > kStackPageSize) {
-    // Generate OOL code (at the end of the function, where the current
-    // assembler is pointing) to do the explicit stack limit check (see
-    // https://docs.microsoft.com/en-us/previous-versions/visualstudio/
-    // visual-studio-6.0/aa227153(v=vs.60)).
-    // At the function start, emit a jump to that OOL code (from {offset} to
+  if (V8_LIKELY(frame_size < 4 * KB)) {
+    // This is the standard case for small frames: just subtract from SP and be
+    // done with it.
+    patching_assembler.sub(sp, sp, Operand(frame_size));
+    patching_assembler.PadWithNops();
+    return;
+  }
+
+  // The frame size is bigger than 4KB, so we might overflow the available stack
+  // space if we first allocate the frame and then do the stack check (we will
+  // need some remaining stack space for throwing the exception). That's why we
+  // check the available stack space before we allocate the frame. To do this we
+  // replace the {__ sub(sp, sp, framesize)} with a jump to OOL code that does
+  // this "extended stack check".
+  //
+  // The OOL code can simply be generated here with the normal assembler,
+  // because all other code generation, including OOL code, has already finished
+  // when {PatchPrepareStackFrame} is called. The function prologue then jumps
+  // to the current {pc_offset()} to execute the OOL code for allocating the
+  // large frame.
+
+  // Emit the unconditional branch in the function prologue (from {offset} to
   // {pc_offset()}).
-    int ool_offset = pc_offset() - offset;
-    patching_assembler.b(ool_offset - Instruction::kPcLoadDelta);
+  patching_assembler.b(pc_offset() - offset - Instruction::kPcLoadDelta);
   patching_assembler.PadWithNops();
 
-    // Now generate the OOL code.
+  // If the frame is bigger than the stack, we throw the stack overflow
+  // exception unconditionally. Thereby we can avoid the integer overflow
+  // check in the condition code.
+  Label continuation;
+  if (frame_size < FLAG_stack_size * 1024) {
+    UseScratchRegisterScope temps(this);
+    Register stack_limit = temps.Acquire();
+    ldr(stack_limit,
+        FieldMemOperand(kWasmInstanceRegister,
+                        WasmInstanceObject::kRealStackLimitAddressOffset));
+    ldr(stack_limit, MemOperand(stack_limit));
+    add(stack_limit, stack_limit, Operand(frame_size));
+    cmp(sp, stack_limit);
+    b(cs /* higher or same */, &continuation);
+  }
+
+  // The instance has not been written to the frame yet (because no frame space
+  // has been allocated), but the runtime call expects it. Hence push it now.
+  Push(kWasmInstanceRegister);
+  Call(wasm::WasmCode::kWasmStackOverflow, RelocInfo::WASM_STUB_CALL);
+  // The call will not return; just define an empty safepoint.
+  safepoint_table_builder->DefineSafepoint(this);
+  if (FLAG_debug_code) stop();
+
+  bind(&continuation);
+
+  // Now allocate the stack space. Note that this might do more than just
+  // decrementing the SP; consult {TurboAssembler::AllocateStackSpace}.
   AllocateStackSpace(frame_size);
-    // Jump back to the start of the function (from {pc_offset()} to {offset +
-    // liftoff::kPatchInstructionsRequired * kInstrSize}).
+
+  // Jump back to the start of the function, from {pc_offset()} to
+  // right after the reserved space for the {sub_sp_32} (which is a branch
+  // now).
   int func_start_offset =
-        offset + liftoff::kPatchInstructionsRequired * kInstrSize - pc_offset();
-    b(func_start_offset - Instruction::kPcLoadDelta);
-    return;
-  }
-#endif
-  patching_assembler.sub(sp, sp, Operand(frame_size));
-  patching_assembler.PadWithNops();
+      offset + liftoff::kPatchInstructionsRequired * kInstrSize;
+  b(func_start_offset - pc_offset() - Instruction::kPcLoadDelta);
 }
 
 void LiftoffAssembler::FinishCode() { CheckConstPool(true, false); }

src/wasm/baseline/arm64/liftoff-assembler-arm64.h

@@ -307,7 +307,8 @@ void LiftoffAssembler::AlignFrameSize() {
   }
 }
 
-void LiftoffAssembler::PatchPrepareStackFrame(int offset) {
+void LiftoffAssembler::PatchPrepareStackFrame(int offset,
+                                              SafepointTableBuilder*) {
   // The frame_size includes the frame marker. The frame marker has already been
   // pushed on the stack though, so we don't need to allocate memory for it
   // anymore.

src/wasm/baseline/ia32/liftoff-assembler-ia32.h

@@ -220,7 +220,8 @@ void LiftoffAssembler::PrepareTailCall(int num_callee_stack_params,
 
 void LiftoffAssembler::AlignFrameSize() {}
 
-void LiftoffAssembler::PatchPrepareStackFrame(int offset) {
+void LiftoffAssembler::PatchPrepareStackFrame(int offset,
+                                              SafepointTableBuilder*) {
   // The frame_size includes the frame marker. The frame marker has already been
   // pushed on the stack though, so we don't need to allocate memory for it
   // anymore.

src/wasm/baseline/liftoff-assembler.h

@@ -654,7 +654,7 @@ class LiftoffAssembler : public TurboAssembler {
   inline void PrepareTailCall(int num_callee_stack_params,
                               int stack_param_delta);
   inline void AlignFrameSize();
-  inline void PatchPrepareStackFrame(int offset);
+  inline void PatchPrepareStackFrame(int offset, SafepointTableBuilder*);
   inline void FinishCode();
   inline void AbortCompilation();
   inline static constexpr int StaticStackFrameSize();

src/wasm/baseline/liftoff-compiler.cc

@@ -310,9 +310,9 @@ void CheckBailoutAllowed(LiftoffBailoutReason reason, const char* detail,
   return;
 #endif
 
-  // TODO(11235): On arm and arm64 there is still a limit on the size of
-  // supported stack frames.
-#if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_ARM64
+  // TODO(11235): On arm64 there is still a limit on the size of supported stack
+  // frames.
+#if V8_TARGET_ARCH_ARM64
   if (strstr(detail, "Stack limited to 512 bytes")) return;
 #endif
 
@@ -954,7 +954,8 @@ class LiftoffCompiler {
       GenerateOutOfLineCode(&ool);
     }
     DCHECK_EQ(frame_size, __ GetTotalFrameSize());
-    __ PatchPrepareStackFrame(pc_offset_stack_frame_construction_);
+    __ PatchPrepareStackFrame(pc_offset_stack_frame_construction_,
+                              &safepoint_table_builder_);
     __ FinishCode();
     safepoint_table_builder_.Emit(&asm_, __ GetTotalFrameSlotCountForGC());
     // Emit the handler table.

src/wasm/baseline/mips/liftoff-assembler-mips.h

@@ -338,7 +338,8 @@ void LiftoffAssembler::PrepareTailCall(int num_callee_stack_params,
 
 void LiftoffAssembler::AlignFrameSize() {}
 
-void LiftoffAssembler::PatchPrepareStackFrame(int offset) {
+void LiftoffAssembler::PatchPrepareStackFrame(int offset,
+                                              SafepointTableBuilder*) {
   // The frame_size includes the frame marker. The frame marker has already been
   // pushed on the stack though, so we don't need to allocate memory for it
   // anymore.

src/wasm/baseline/mips64/liftoff-assembler-mips64.h

@@ -325,7 +325,8 @@ void LiftoffAssembler::PrepareTailCall(int num_callee_stack_params,
 
 void LiftoffAssembler::AlignFrameSize() {}
 
-void LiftoffAssembler::PatchPrepareStackFrame(int offset) {
+void LiftoffAssembler::PatchPrepareStackFrame(int offset,
+                                              SafepointTableBuilder*) {
   // The frame_size includes the frame marker. The frame marker has already been
   // pushed on the stack though, so we don't need to allocate memory for it
   // anymore.

src/wasm/baseline/ppc/liftoff-assembler-ppc.h

@@ -110,7 +110,8 @@ void LiftoffAssembler::PrepareTailCall(int num_callee_stack_params,
 
 void LiftoffAssembler::AlignFrameSize() {}
 
-void LiftoffAssembler::PatchPrepareStackFrame(int offset) {
+void LiftoffAssembler::PatchPrepareStackFrame(int offset,
+                                              SafepointTableBuilder*) {
   bailout(kUnsupportedArchitecture, "PatchPrepareStackFrame");
 }
 

src/wasm/baseline/riscv64/liftoff-assembler-riscv64.h

@@ -311,7 +311,8 @@ void LiftoffAssembler::PrepareTailCall(int num_callee_stack_params,
 
 void LiftoffAssembler::AlignFrameSize() {}
 
-void LiftoffAssembler::PatchPrepareStackFrame(int offset) {
+void LiftoffAssembler::PatchPrepareStackFrame(int offset,
+                                              SafepointTableBuilder*) {
   int frame_size = GetTotalFrameSize() - kSystemPointerSize;
   // We can't run out of space, just pass anything big enough to not cause the
   // assembler to try to grow the buffer.

src/wasm/baseline/s390/liftoff-assembler-s390.h

@@ -122,7 +122,8 @@ void LiftoffAssembler::PrepareTailCall(int num_callee_stack_params,
 
 void LiftoffAssembler::AlignFrameSize() {}
 
-void LiftoffAssembler::PatchPrepareStackFrame(int offset) {
+void LiftoffAssembler::PatchPrepareStackFrame(int offset,
+                                              SafepointTableBuilder*) {
   int frame_size = GetTotalFrameSize() - kSystemPointerSize;
 
   constexpr int LayInstrSize = 6;

src/wasm/baseline/x64/liftoff-assembler-x64.h

@@ -206,7 +206,8 @@ void LiftoffAssembler::AlignFrameSize() {
   max_used_spill_offset_ = RoundUp(max_used_spill_offset_, kSystemPointerSize);
 }
 
-void LiftoffAssembler::PatchPrepareStackFrame(int offset) {
+void LiftoffAssembler::PatchPrepareStackFrame(int offset,
+                                              SafepointTableBuilder*) {
   // The frame_size includes the frame marker. The frame marker has already been
   // pushed on the stack though, so we don't need to allocate memory for it
   // anymore.