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QRandomGenerator: improve internal noexceptness

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There are a couple of Q_ASSERT wrapped by the new noexcepts, but most of
those aren't validation of external parameters, only of internal
construction. The two exceptions are the checks for pointer alignment.

Change-Id: I0a103569c81b4711a649fffd14ec8523d741dfb6
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
This commit is contained in:
Thiago Macieira 2017-10-11 14:52:44 +02:00
parent 0a98f790bf
commit 13b6c1e625
1 changed files with 7 additions and 5 deletions
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12
src/corelib/global/qrandom.cpp
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@ -95,7 +95,7 @@ DECLSPEC_IMPORT BOOLEAN WINAPI SystemFunction036(PVOID RandomBuffer, ULONG Rando
QT_BEGIN_NAMESPACE QT_BEGIN_NAMESPACE
#if defined(Q_PROCESSOR_X86) && QT_COMPILER_SUPPORTS_HERE(RDRND) #if defined(Q_PROCESSOR_X86) && QT_COMPILER_SUPPORTS_HERE(RDRND)
static qssize_t qt_random_cpu(void *buffer, qssize_t count); static qssize_t qt_random_cpu(void *buffer, qssize_t count) Q_DECL_NOTHROW;
# ifdef Q_PROCESSOR_X86_64 # ifdef Q_PROCESSOR_X86_64
# define _rdrandXX_step _rdrand64_step # define _rdrandXX_step _rdrand64_step
@ -103,7 +103,7 @@ static qssize_t qt_random_cpu(void *buffer, qssize_t count);
# define _rdrandXX_step _rdrand32_step # define _rdrandXX_step _rdrand32_step
# endif # endif
static QT_FUNCTION_TARGET(RDRND) qssize_t qt_random_cpu(void *buffer, qssize_t count) static QT_FUNCTION_TARGET(RDRND) qssize_t qt_random_cpu(void *buffer, qssize_t count) Q_DECL_NOTHROW
{ {
unsigned *ptr = reinterpret_cast<unsigned *>(buffer); unsigned *ptr = reinterpret_cast<unsigned *>(buffer);
unsigned *end = ptr + count; unsigned *end = ptr + count;
@ -213,7 +213,7 @@ class SystemRandom
{ {
public: public:
enum { EfficientBufferFill = true }; enum { EfficientBufferFill = true };
static qssize_t fillBuffer(void *buffer, qssize_t count) static qssize_t fillBuffer(void *buffer, qssize_t count) Q_DECL_NOTHROW
{ {
auto RtlGenRandom = SystemFunction036; auto RtlGenRandom = SystemFunction036;
return RtlGenRandom(buffer, ULONG(count)) ? count: 0; return RtlGenRandom(buffer, ULONG(count)) ? count: 0;
@ -224,7 +224,7 @@ class SystemRandom
{ {
public: public:
enum { EfficientBufferFill = false }; enum { EfficientBufferFill = false };
static qssize_t fillBuffer(void *, qssize_t) static qssize_t fillBuffer(void *, qssize_t) Q_DECL_NOTHROW
{ {
// always use the fallback // always use the fallback
return 0; return 0;
@ -351,7 +351,7 @@ static Q_NORETURN void fallback_fill(quint32 *, qssize_t)
} }
#endif #endif
static qssize_t fill_cpu(quint32 *buffer, qssize_t count) static qssize_t fill_cpu(quint32 *buffer, qssize_t count) Q_DECL_NOTHROW
{ {
#if defined(Q_PROCESSOR_X86) && QT_COMPILER_SUPPORTS_HERE(RDRND) #if defined(Q_PROCESSOR_X86) && QT_COMPILER_SUPPORTS_HERE(RDRND)
if (qCpuHasFeature(RDRND) && (uint(qt_randomdevice_control) & SkipHWRNG) == 0) if (qCpuHasFeature(RDRND) && (uint(qt_randomdevice_control) & SkipHWRNG) == 0)
@ -364,6 +364,7 @@ static qssize_t fill_cpu(quint32 *buffer, qssize_t count)
} }
static void fill_internal(quint32 *buffer, qssize_t count) static void fill_internal(quint32 *buffer, qssize_t count)
Q_DECL_NOEXCEPT_EXPR(noexcept(SystemRandom::fillBuffer(buffer, count)))
{ {
if (Q_UNLIKELY(uint(qt_randomdevice_control) & SetRandomData)) { if (Q_UNLIKELY(uint(qt_randomdevice_control) & SetRandomData)) {
uint value = uint(qt_randomdevice_control) & RandomDataMask; uint value = uint(qt_randomdevice_control) & RandomDataMask;
@ -387,6 +388,7 @@ static void fill_internal(quint32 *buffer, qssize_t count)
} }
static Q_NEVER_INLINE void fill(void *buffer, void *bufferEnd) static Q_NEVER_INLINE void fill(void *buffer, void *bufferEnd)
Q_DECL_NOEXCEPT_EXPR(noexcept(fill_internal(static_cast<quint32 *>(buffer), 1)))
{ {
struct ThreadState { struct ThreadState {
enum { enum {