proxy_ptr.test.cc

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#include <gtest/gtest.h>
 
#include <vector>
 
#include "sim/proxy_ptr.hh"
 
using namespace gem5;
 
struct Access
{
    bool read;
    Addr addr;
    Addr size;
 
    Access(bool _read, Addr _addr, Addr _size) :
        read(_read), addr(_addr), size(_size)
    {}
 
    bool
    operator == (const Access &other) const
    {
        return read == other.read &&
               addr == other.addr &&
               size == other.size;
    }
 
    bool
    operator != (const Access &other) const
    {
        return !(*this == other);
    }
};
 
using Accesses = std::vector<Access>;
 
class BackingStore
{
  public:
    std::vector<uint8_t> store;
    Addr base;
 
    BackingStore(Addr _base, size_t _size) : store(_size, 0), base(_base) {}
 
    void
    rangeCheck(Addr addr, Addr size)
    {
        panic_if(addr < base || addr + size > base + store.size(),
                 "Range [%#x,%#x) outside of [%#x,%#x).",
                 addr, addr + size, base, base + store.size());
    }
 
    mutable Accesses accesses;
 
    ::testing::AssertionResult
    expect_access(size_t idx, const Access &other) const
    {
        if (idx >= accesses.size()) {
            return ::testing::AssertionFailure() << "index " << idx <<
                " out of bounds";
        }
 
        if (accesses[idx] != other) {
            return ::testing::AssertionFailure() << "access[" << idx <<
                "] was " << accesses[idx] << ", expected " << other;
        }
        return ::testing::AssertionSuccess();
    }
 
    ::testing::AssertionResult
    expect_accesses(Accesses expected) const
    {
        if (accesses.size() != expected.size()) {
            return ::testing::AssertionFailure() <<
                "Wrong number of accesses, was " << accesses.size() <<
                " expected " << expected.size();
        }
 
        auto failure = ::testing::AssertionFailure();
        bool success = true;
        if (accesses.size() == expected.size()) {
            for (size_t idx = 0; idx < expected.size(); idx++) {
                auto result = expect_access(idx, expected[idx]);
                if (!result) {
                    failure << result.message();
                    success = false;
                }
            }
        }
 
        if (!success)
            return failure;
        else
            return ::testing::AssertionSuccess();
    }
 
    void
    writeBlob(Addr ptr, const void *data, int size)
    {
        rangeCheck(ptr, size);
        accesses.emplace_back(false, ptr, size);
        memcpy(store.data() + (ptr - base), data, size);
    }
 
    void
    readBlob(Addr ptr, void *data, int size)
    {
        rangeCheck(ptr, size);
        accesses.emplace_back(true, ptr, size);
        memcpy(data, store.data() + (ptr - base), size);
    }
};
 
::testing::AssertionResult
accessed(const char *expr1, const char *expr2,
         const BackingStore &store, const Accesses &expected)
{
    return store.expect_accesses(expected);
}
 
#define EXPECT_ACCESSES(store, ...) \
    do { \
        Accesses expected({__VA_ARGS__}); \
        EXPECT_PRED_FORMAT2(accessed, store, expected); \
        store.accesses.clear(); \
    } while (false)
 
std::ostream &
operator << (std::ostream &os, const Access &access)
{
    ccprintf(os, "%s(%#x, %d)", access.read ? "read" : "write",
            access.addr, access.size);
    return os;
}
 
class TestProxy
{
  public:
    BackingStore &store;
 
    TestProxy(BackingStore &_store) : store(_store) {}
    // Sneaky constructor for testing guest_abi integration.
    TestProxy(ThreadContext *tc) : store(*(BackingStore *)tc) {}
 
    void
    writeBlob(Addr ptr, const void *data, int size)
    {
        store.writeBlob(ptr, data, size);
    }
 
    void
    readBlob(Addr ptr, void *data, int size)
    {
        store.readBlob(ptr, data, size);
    }
};
 
template <typename T>
using TestPtr = ProxyPtr<T, TestProxy>;
 
template <typename T>
using ConstTestPtr = ConstProxyPtr<T, TestProxy>;
 
TEST(ProxyPtr, Clean)
{
    BackingStore store(0x1000, 0x1000);
 
    EXPECT_ACCESSES(store);
 
    {
        ConstTestPtr<uint32_t> test_ptr(0x1100, store);
 
        EXPECT_ACCESSES(store, { true, test_ptr.addr(), sizeof(uint32_t) });
    }
 
    EXPECT_ACCESSES(store);
 
    {
        TestPtr<uint32_t> test_ptr(0x1100, store);
 
        EXPECT_ACCESSES(store, { true, test_ptr.addr(), sizeof(uint32_t) });
    }
 
    EXPECT_ACCESSES(store);
}
 
TEST(ProxyPtr, Dirty)
{
    BackingStore store(0x1000, 0x1100);
 
    EXPECT_ACCESSES(store);
 
    {
        TestPtr<uint32_t> test_ptr(0x1100, store);
 
        *test_ptr = 0xa5a5a5a5;
 
        EXPECT_ACCESSES(store, { true, test_ptr.addr(), sizeof(uint32_t) });
    }
 
    EXPECT_ACCESSES(store, { false, 0x1100, sizeof(uint32_t) });
    EXPECT_EQ(store.store[0x100], 0xa5);
    EXPECT_EQ(store.store[0x101], 0xa5);
    EXPECT_EQ(store.store[0x102], 0xa5);
    EXPECT_EQ(store.store[0x103], 0xa5);
}
 
 
TEST(ProxyPtr, LoadAndFlush)
{
    BackingStore store(0x1000, 0x1100);
 
    store.store[0x100] = 0xa5;
    store.store[0x101] = 0xa5;
    store.store[0x102] = 0xa5;
    store.store[0x103] = 0xa5;
 
    TestPtr<uint32_t> test_ptr(0x1100, store);
 
    // Check that the backing store is unmodified.
    EXPECT_EQ(store.store[0x100], 0xa5);
    EXPECT_EQ(store.store[0x101], 0xa5);
    EXPECT_EQ(store.store[0x102], 0xa5);
    EXPECT_EQ(store.store[0x103], 0xa5);
 
    // Change the value in our local buffered copy.
    *test_ptr = 0x5a5a5a5a;
 
    // Verify that the backing store hasn't been changed.
    EXPECT_EQ(store.store[0x100], 0xa5);
    EXPECT_EQ(store.store[0x101], 0xa5);
    EXPECT_EQ(store.store[0x102], 0xa5);
    EXPECT_EQ(store.store[0x103], 0xa5);
 
    // Flush out our modifications.
    test_ptr.flush();
 
    // Verify that they've been written back to the store.
    EXPECT_EQ(store.store[0x100], 0x5a);
    EXPECT_EQ(store.store[0x101], 0x5a);
    EXPECT_EQ(store.store[0x102], 0x5a);
    EXPECT_EQ(store.store[0x103], 0x5a);
 
    // Update the store and try to flush again.
    store.store[0x100] = 0xaa;
    test_ptr.flush();
 
    // Verify that no flush happened, since our ptr was "clean".
    EXPECT_EQ(store.store[0x100], 0xaa);
 
    // Force a flush.
    test_ptr.flush(true);
 
    // Verify that the flush happened even though the ptr was "clean".
    EXPECT_EQ(store.store[0x100], 0x5a);
 
    // Update the store.
    store.store[0x100] = 0xa5;
    store.store[0x101] = 0xa5;
    store.store[0x102] = 0xa5;
    store.store[0x103] = 0xa5;
 
    // Verify that our local copy hasn't changed.
    EXPECT_EQ(*(const uint32_t *)test_ptr, 0x5a5a5a5a);
 
    // Reload the pointer from the store.
    test_ptr.load();
    EXPECT_EQ(*(const uint32_t *)test_ptr, 0xa5a5a5a5);
}
 
TEST(ProxyPtr, ConstOperators)
{
    bool is_same;
 
    BackingStore store(0x1000, 0x1000);
 
    const Addr addr1 = 0x1100;
    const Addr addr2 = 0x1200;
 
    using PtrType = uint32_t;
 
    ConstTestPtr<PtrType> test_ptr1(addr1, store);
    EXPECT_EQ(test_ptr1.addr(), addr1);
 
    ConstTestPtr<PtrType> test_ptr2(addr2, store);
    EXPECT_EQ(test_ptr2.addr(), addr2);
 
    // Pointer +/- integer.
    auto next_ptr = test_ptr1 + 2;
    EXPECT_EQ(next_ptr.addr(), addr1 + 2 * sizeof(PtrType));
 
    auto reverse_next_ptr = 2 + test_ptr1;
    EXPECT_EQ(reverse_next_ptr.addr(), addr1 + 2 * sizeof(PtrType));
 
    auto prev_ptr = test_ptr1 - 2;
    EXPECT_EQ(prev_ptr.addr(), addr1 - 2 * sizeof(PtrType));
 
    // Pointer-pointer subtraction.
    auto diff = test_ptr2 - test_ptr1;
    EXPECT_EQ(diff, (addr2 - addr1) / sizeof(PtrType));
 
    // Assignment.
    ConstTestPtr<PtrType> target(addr2, store);
    EXPECT_EQ(target.addr(), addr2);
 
    target = test_ptr1;
    EXPECT_EQ(target.addr(), addr1);
 
    // Conversions.
    EXPECT_TRUE(test_ptr1);
    ConstTestPtr<PtrType> null(0, store);
    EXPECT_FALSE(null);
 
    EXPECT_NE((const PtrType *)test_ptr1, nullptr);
    EXPECT_EQ((const PtrType *)null, nullptr);
 
    // Dereferences.
    is_same = std::is_same_v<decltype(*test_ptr1), const PtrType &>;
    EXPECT_TRUE(is_same);
 
    store.store[0x100] = 0x55;
    store.store[0x101] = 0x55;
    store.store[0x102] = 0x55;
    store.store[0x103] = 0x55;
 
    // Force an update since we changed the backing store behind our ptrs back.
    test_ptr1.load();
 
    EXPECT_EQ(*test_ptr1, 0x55555555);
 
    store.store[0x100] = 0x11;
    store.store[0x101] = 0x22;
    store.store[0x102] = 0x33;
    store.store[0x103] = 0x44;
 
    struct TestStruct
    {
        uint8_t a;
        uint8_t b;
        uint8_t c;
        uint8_t d;
    };
 
    ConstTestPtr<TestStruct> struct_ptr(addr1, store);
    EXPECT_EQ(struct_ptr->a, 0x11);
    EXPECT_EQ(struct_ptr->b, 0x22);
    EXPECT_EQ(struct_ptr->c, 0x33);
    EXPECT_EQ(struct_ptr->d, 0x44);
 
    is_same = std::is_same_v<decltype((struct_ptr->a)), const uint8_t &>;
    EXPECT_TRUE(is_same);
}
 
TEST(ProxyPtr, NonConstOperators)
{
    bool is_same;
 
    BackingStore store(0x1000, 0x1000);
 
    const Addr addr1 = 0x1100;
    const Addr addr2 = 0x1200;
 
    using PtrType = uint32_t;
 
    TestPtr<PtrType> test_ptr1(addr1, store);
    EXPECT_EQ(test_ptr1.addr(), addr1);
 
    TestPtr<PtrType> test_ptr2(addr2, store);
    EXPECT_EQ(test_ptr2.addr(), addr2);
 
    // Pointer +/- integer.
    auto next_ptr = test_ptr1 + 2;
    EXPECT_EQ(next_ptr.addr(), addr1 + 2 * sizeof(PtrType));
 
    auto reverse_next_ptr = 2 + test_ptr1;
    EXPECT_EQ(reverse_next_ptr.addr(), addr1 + 2 * sizeof(PtrType));
 
    auto prev_ptr = test_ptr1 - 2;
    EXPECT_EQ(prev_ptr.addr(), addr1 - 2 * sizeof(PtrType));
 
    // Pointer-pointer subtraction.
    auto diff = test_ptr2 - test_ptr1;
    EXPECT_EQ(diff, (addr2 - addr1) / sizeof(PtrType));
 
    // Assignment.
    TestPtr<PtrType> target(addr2, store);
    EXPECT_EQ(target.addr(), addr2);
 
    target = test_ptr1;
    EXPECT_EQ(target.addr(), addr1);
 
    // Conversions.
    EXPECT_TRUE(test_ptr1);
    TestPtr<PtrType> null(0, store);
    EXPECT_FALSE(null);
 
    EXPECT_NE((PtrType *)test_ptr1, nullptr);
    EXPECT_EQ((PtrType *)null, nullptr);
    EXPECT_NE((const PtrType *)test_ptr1, nullptr);
    EXPECT_EQ((const PtrType *)null, nullptr);
 
    // Dereferences.
    is_same = std::is_same_v<decltype(*test_ptr1), PtrType &>;
    EXPECT_TRUE(is_same);
 
    // Flush test_ptr1, which has been conservatively marked as dirty.
    test_ptr1.flush();
 
    store.store[0x100] = 0x55;
    store.store[0x101] = 0x55;
    store.store[0x102] = 0x55;
    store.store[0x103] = 0x55;
 
    // Force an update since we changed the backing store behind our ptrs back.
    test_ptr1.load();
 
    EXPECT_EQ(*test_ptr1, 0x55555555);
 
    store.store[0x100] = 0x11;
    store.store[0x101] = 0x22;
    store.store[0x102] = 0x33;
    store.store[0x103] = 0x44;
 
    struct TestStruct
    {
        uint8_t a;
        uint8_t b;
        uint8_t c;
        uint8_t d;
    };
 
    TestPtr<TestStruct> struct_ptr(addr1, store);
    EXPECT_EQ(struct_ptr->a, 0x11);
    EXPECT_EQ(struct_ptr->b, 0x22);
    EXPECT_EQ(struct_ptr->c, 0x33);
    EXPECT_EQ(struct_ptr->d, 0x44);
 
    is_same = std::is_same_v<decltype((struct_ptr->a)), uint8_t &>;
    EXPECT_TRUE(is_same);
}
 
struct TestABI
{
    using UintPtr = uint64_t;
    using State = int;
};
 
namespace gem5
{
 
namespace guest_abi
{
 
template <>
struct Argument<TestABI, Addr>
{
    static Addr
    get(ThreadContext *tc, typename TestABI::State &state)
    {
        return 0x1000;
    }
};
 
} // namespace guest_abi
} // namespace gem5
 
bool abiCalled = false;
bool abiCalledConst = false;
 
void
abiTestFunc(ThreadContext *tc, TestPtr<uint8_t> ptr)
{
    abiCalled = true;
    EXPECT_EQ(ptr.addr(), 0x1000);
}
 
void
abiTestFuncConst(ThreadContext *tc, ConstTestPtr<uint8_t> ptr)
{
    abiCalledConst = true;
    EXPECT_EQ(ptr.addr(), 0x1000);
}
 
TEST(ProxyPtrTest, GuestABI)
{
    BackingStore store(0x1000, 0x1000);
 
    EXPECT_FALSE(abiCalled);
    EXPECT_FALSE(abiCalledConst);
 
    invokeSimcall<TestABI>((ThreadContext *)&store, abiTestFunc);
 
    EXPECT_TRUE(abiCalled);
    EXPECT_FALSE(abiCalledConst);
 
    invokeSimcall<TestABI>((ThreadContext *)&store, abiTestFuncConst);
 
    EXPECT_TRUE(abiCalled);
    EXPECT_TRUE(abiCalledConst);
}