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// Copyright 2020 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/heap/cppgc/stack.h"
#include <memory>
#include <ostream>
#include "include/v8config.h"
#include "src/base/platform/platform.h"
#include "testing/gtest/include/gtest/gtest.h"
#if V8_OS_LINUX && (V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64)
#include <xmmintrin.h>
#endif
namespace cppgc {
namespace internal {
namespace {
class GCStackTest : public ::testing::Test {
protected:
void SetUp() override {
stack_.reset(new Stack(v8::base::Stack::GetStackStart()));
}
void TearDown() override { stack_.reset(); }
Stack* GetStack() const { return stack_.get(); }
private:
std::unique_ptr<Stack> stack_;
};
} // namespace
TEST_F(GCStackTest, IsOnStackForStackValue) {
void* dummy;
EXPECT_TRUE(GetStack()->IsOnStack(&dummy));
}
TEST_F(GCStackTest, IsOnStackForHeapValue) {
auto dummy = std::make_unique<int>();
EXPECT_FALSE(GetStack()->IsOnStack(dummy.get()));
}
#ifdef CPPGC_SUPPORTS_CONSERVATIVE_STACK_SCAN
namespace {
class StackScanner final : public StackVisitor {
public:
struct Container {
std::unique_ptr<int> value;
};
StackScanner() : container_(new Container{}) {
container_->value = std::make_unique<int>();
}
void VisitPointer(const void* address) final {
if (address == container_->value.get()) found_ = true;
}
void Reset() { found_ = false; }
bool found() const { return found_; }
int* needle() const { return container_->value.get(); }
private:
std::unique_ptr<Container> container_;
bool found_ = false;
};
} // namespace
TEST_F(GCStackTest, IteratePointersFindsOnStackValue) {
auto scanner = std::make_unique<StackScanner>();
// No check that the needle is initially not found as on some platforms it
// may be part of the redzone or temporaries after setting it up throuhg
// StackScanner.
{
int* volatile tmp = scanner->needle();
USE(tmp);
GetStack()->IteratePointers(scanner.get());
EXPECT_TRUE(scanner->found());
}
}
TEST_F(GCStackTest, IteratePointersFindsOnStackValuePotentiallyUnaligned) {
auto scanner = std::make_unique<StackScanner>();
// No check that the needle is initially not found as on some platforms it
// may be part of the redzone or temporaries after setting it up throuhg
// StackScanner.
{
char a = 'c';
USE(a);
int* volatile tmp = scanner->needle();
USE(tmp);
GetStack()->IteratePointers(scanner.get());
EXPECT_TRUE(scanner->found());
}
}
namespace {
void RecursivelyPassOnParameter(int* volatile p1, int* volatile p2,
int* volatile p3, int* volatile p4,
int* volatile p5, int* volatile p6,
int* volatile p7, int* volatile p8,
Stack* stack, StackVisitor* visitor) {
if (p1) {
RecursivelyPassOnParameter(nullptr, p1, nullptr, nullptr, nullptr, nullptr,
nullptr, nullptr, stack, visitor);
} else if (p2) {
RecursivelyPassOnParameter(nullptr, nullptr, p2, nullptr, nullptr, nullptr,
nullptr, nullptr, stack, visitor);
} else if (p3) {
RecursivelyPassOnParameter(nullptr, nullptr, nullptr, p3, nullptr, nullptr,
nullptr, nullptr, stack, visitor);
} else if (p4) {
RecursivelyPassOnParameter(nullptr, nullptr, nullptr, nullptr, p4, nullptr,
nullptr, nullptr, stack, visitor);
} else if (p5) {
RecursivelyPassOnParameter(nullptr, nullptr, nullptr, nullptr, nullptr, p5,
nullptr, nullptr, stack, visitor);
} else if (p6) {
RecursivelyPassOnParameter(nullptr, nullptr, nullptr, nullptr, nullptr,
nullptr, p6, nullptr, stack, visitor);
} else if (p7) {
RecursivelyPassOnParameter(nullptr, nullptr, nullptr, nullptr, nullptr,
nullptr, nullptr, p7, stack, visitor);
} else if (p8) {
stack->IteratePointers(visitor);
}
}
} // namespace
TEST_F(GCStackTest, IteratePointersFindsParameter) {
auto scanner = std::make_unique<StackScanner>();
// No check that the needle is initially not found as on some platforms it
// may be part of the redzone or temporaries after setting it up throuhg
// StackScanner.
RecursivelyPassOnParameter(nullptr, nullptr, nullptr, nullptr, nullptr,
nullptr, nullptr, scanner->needle(), GetStack(),
scanner.get());
EXPECT_TRUE(scanner->found());
}
TEST_F(GCStackTest, IteratePointersFindsParameterInNestedFunction) {
auto scanner = std::make_unique<StackScanner>();
// No check that the needle is initially not found as on some platforms it
// may be part of the redzone or temporaries after setting it up throuhg
// StackScanner.
RecursivelyPassOnParameter(scanner->needle(), nullptr, nullptr, nullptr,
nullptr, nullptr, nullptr, nullptr, GetStack(),
scanner.get());
EXPECT_TRUE(scanner->found());
}
// The following test uses inline assembly and has been checked to work on clang
// to verify that the stack-scanning trampoline pushes callee-saved registers.
//
// The test uses a macro loop as asm() can only be passed string literals.
#ifdef __clang__
#ifdef V8_TARGET_ARCH_X64
#ifdef V8_OS_WIN
// Excluded from test: rbp
#define FOR_ALL_CALLEE_SAVED_REGS(V) \
V("rdi") \
V("rsi") \
V("rbx") \
V("r12") \
V("r13") \
V("r14") \
V("r15")
#else // !V8_OS_WIN
// Excluded from test: rbp
#define FOR_ALL_CALLEE_SAVED_REGS(V) \
V("rbx") \
V("r12") \
V("r13") \
V("r14") \
V("r15")
#endif // !V8_OS_WIN
#endif // V8_TARGET_ARCH_X64
#endif // __clang__
#ifdef FOR_ALL_CALLEE_SAVED_REGS
TEST_F(GCStackTest, IteratePointersFindsCalleeSavedRegisters) {
auto scanner = std::make_unique<StackScanner>();
// No check that the needle is initially not found as on some platforms it
// may be part of the redzone or temporaries after setting it up throuhg
// StackScanner.
// First, clear all callee-saved registers.
#define CLEAR_REGISTER(reg) asm("mov $0, %%" reg : : : reg);
FOR_ALL_CALLEE_SAVED_REGS(CLEAR_REGISTER)
#undef CLEAR_REGISTER
// Keep local raw pointers to keep instruction sequences small below.
auto* local_stack = GetStack();
auto* local_scanner = scanner.get();
// Moves |local_scanner->needle()| into a callee-saved register, leaving the
// callee-saved register as the only register referencing the needle.
// (Ignoring implementation-dependent dirty registers/stack.)
#define KEEP_ALIVE_FROM_CALLEE_SAVED(reg) \
local_scanner->Reset(); \
/* This moves the temporary into the calee-saved register. */ \
asm("mov %0, %%" reg : : "r"(local_scanner->needle()) : reg); \
/* Register is unprotected from here till the actual invocation. */ \
local_stack->IteratePointers(local_scanner); \
EXPECT_TRUE(local_scanner->found()) \
<< "pointer in callee-saved register not found. register: " << reg \
<< std::endl; \
/* Clear out the register again */ \
asm("mov $0, %%" reg : : : reg);
FOR_ALL_CALLEE_SAVED_REGS(KEEP_ALIVE_FROM_CALLEE_SAVED)
#undef KEEP_ALIVE_FROM_CALLEE_SAVED
#undef FOR_ALL_CALLEE_SAVED_REGS
}
#endif // FOR_ALL_CALLEE_SAVED_REGS
#if V8_OS_LINUX && (V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64)
class CheckStackAlignmentVisitor final : public StackVisitor {
public:
void VisitPointer(const void*) final {
float f[4] = {0.};
volatile auto xmm = ::_mm_load_ps(f);
USE(xmm);
}
};
TEST_F(GCStackTest, StackAlignment) {
auto checker = std::make_unique<CheckStackAlignmentVisitor>();
GetStack()->IteratePointers(checker.get());
}
#endif // V8_OS_LINUX && (V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64)
#endif // CPPGC_SUPPORTS_CONSERVATIVE_STACK_SCAN
} // namespace internal
} // namespace cppgc
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