smith
22058efe41
Fixing various bugs all over the VM that make assumptions about RefData and TypedValue layout. Here are the assumptions fixed by this diff: offsetof(RefData, m_tv) == 0. Both JIT's assumed this in many subtle ways, by punning RefData* as TypedValue* without adding an offset. This assumption also causes RefData._count to overlap TypedValue.m_aux, which constraints TypedValue layout. offsetof(TypedValue, m_data) == 0. gen_ext_hhvm.php assumes you can cast TypedValue* to Value*; the JITs often weren't using offsetof(TypedValue, m_data) in their addressing calculations. HHIR assumed return-by-value TV's have m_data/m_type in rax/rdx, which can change when TV layout changes. offsetof(TypedValue, m_type) > 8 is an assumption baked into the pass-by-value register assignment logic in HHIR's codegen.cpp; if the type is in the low word, register assignment is swapped. sizeof(TypedValue::m_type) == 4. We used dword-sized operations in both JIT's when accessing m_type. Now, we use helper functions that are sensitive to sizeof(DataType) Configuration: DEBUG=: (opt) same layouts as trunk for RefData & TypedValue DEBUG=1: (dbg) new RefData layout (m_tv doesn't overlap RefData::_count) PACKED_TV=1, DEBUG=*: new RefData and TypedValue layout.
137 linhas
4.5 KiB
C++
137 linhas
4.5 KiB
C++
/*
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+----------------------------------------------------------------------+
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| HipHop for PHP |
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+----------------------------------------------------------------------+
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| Copyright (c) 2010- Facebook, Inc. (http://www.facebook.com) |
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+----------------------------------------------------------------------+
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| This source file is subject to version 3.01 of the PHP license, |
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| that is bundled with this package in the file LICENSE, and is |
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| available through the world-wide-web at the following url: |
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| http://www.php.net/license/3_01.txt |
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| If you did not receive a copy of the PHP license and are unable to |
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| obtain it through the world-wide-web, please send a note to |
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| license@php.net so we can mail you a copy immediately. |
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+----------------------------------------------------------------------+
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*/
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#ifndef __INSIDE_HPHP_COMPLEX_TYPES_H__
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#error Directly including 'hphp_value.h' is prohibited. \
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Include 'complex_types.h' instead.
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#endif
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#ifndef __HPHP_HPHPVALUE_H__
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#define __HPHP_HPHPVALUE_H__
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#include <runtime/base/types.h>
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namespace HPHP {
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///////////////////////////////////////////////////////////////////////////////
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namespace VM {
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class Class;
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}
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struct TypedValue;
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/*
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* This is the payload of a PHP value. This union may only be used in
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* contexts that have a discriminator, e.g. in TypedValue (below), or
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* when the type is known beforehand.
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*/
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union Value {
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int64_t num; // KindOfInt64, KindOfBool (must be zero-extended)
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double dbl; // KindOfDouble
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StringData *pstr; // KindOfString, KindOfStaticString
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ArrayData *parr; // KindOfArray
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ObjectData *pobj; // KindOfObject
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VM::Class *pcls; // only in vm stack, no type tag.
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RefData *pref; // KindOfRef
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TypedValue *pind; // only for KindOfIndirect
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};
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enum VarNrFlag { NR_FLAG = 1<<29 };
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union AuxUnion {
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int32_t u_hash; // key type and hash for HphpArray and [Stable]Map
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VarNrFlag u_varNrFlag; // magic number for asserts in VarNR
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bool u_deepInit; // used by Class::initPropsImpl for deep init
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int32_t u_cacheHandle; // used by unit.cpp to squirrel away cache handles
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};
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/*
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* 7pack format:
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* experimental "Packed" format for TypedValues. By grouping 7 tags
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* and 7 values separately, we can fit 7 TypedValues in 63 bytes (64 with
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* a throw-away alignment byte (t0):
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*
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* 0 1 2 7 8 16 56
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* [t0][t1][t2]..[t7][value1][value2]..[value7]
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*
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* With this layout, a single TypedValue requires 16 bytes, and still has
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* room for a 32-bit padding field, which we still use in a few places:
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*
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* 0 1 2 3 4 8
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* [t0][m_type][t2][t3][m_pad][m_data]
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*/
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/*
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* A TypedValue is a descriminated PHP Value. m_tag describes the contents
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* of m_data. m_aux is described above, and must only be read or written
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* in specialized contexts.
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*/
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#ifdef PACKED_TV
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// This TypedValue layout is a subset of the full 7pack format. Client
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// code should not mess with the _t0 or _tags padding fields.
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struct TypedValue {
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union {
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uint8_t _tags[8];
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struct {
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uint8_t _t0;
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DataType m_type;
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AuxUnion m_aux;
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};
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};
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Value m_data;
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std::string pretty() const;
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};
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#else
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struct TypedValue {
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Value m_data;
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AuxUnion m_aux;
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DataType m_type;
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std::string pretty() const; // debug formatting. see trace.h
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};
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#endif
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/*
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* This TypedValue subclass exposes a 32-bit "aux" field somewhere inside it.
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* For now, access the m_aux field declared in TypedValue, but once we
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* rearrange TypedValue, the aux field can move down to this struct.
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* TODO: t1100154 phase this out completely.
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*/
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struct TypedValueAux : TypedValue {
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static const size_t auxOffset = offsetof(TypedValue, m_aux);
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static const size_t auxSize = sizeof(m_aux);
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int32_t& hash() { return m_aux.u_hash; }
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const int32_t& hash() const { return m_aux.u_hash; }
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int32_t& cacheHandle() { return m_aux.u_cacheHandle; }
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const int32_t& cacheHandle() const { return m_aux.u_cacheHandle; }
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bool& deepInit() { return m_aux.u_deepInit; }
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const bool& deepInit() const { return m_aux.u_deepInit; }
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VarNrFlag& varNrFlag() { return m_aux.u_varNrFlag; }
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const VarNrFlag& varNrFlag() const { return m_aux.u_varNrFlag; }
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private:
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static void assertions() {
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static_assert(sizeof(TypedValueAux) <= 16,
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"don't add big things to AuxUnion");
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}
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};
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///////////////////////////////////////////////////////////////////////////////
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}
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#endif // __HPHP_HPHPVALUE_H__
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