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by: D语言论坛 http://www.d-programming-language-china.org
from: http://www.digitalmars.com/d/abi.html
version: 基于D 1.013 (Apr 19, 2007)
如果 D 实现符合 D ABI （应用程序二进制接口）的话，就可以生成可以同其他实现互操作的库、DLL等。
这份规范的大部分都处于 TBD（尚未完成）状态。
C ABI
本规范中提到的 C ABI 指的是目标系统中的 C 应用程序二进制接口。C 和 D 代码应该能够自由地链接到一起，尤其是，D 代码应该能够访问所有的 C ABI 运行时库。
Basic Types
TBD
Structs结构
符合目标平台上的 C ABI 结构分布。
Classes类
一个对象的组成如下：
| offset | contents |
|---|
| 0 | pointer to vtable |
| ptrsize | monitor |
| ptrsize*2... | non-static members |
vtable 的组成为：( 本文出处: http://www.d-programming-language-china.org )
| offset | contents |
|---|
| 0 | pointer to instance of ClassInfo |
| ptrsize... | pointers to virtual member functions |
类定义:
生成了：
一个叫做 ClassXXXX 的 Class 类的实例。
一个叫做 StaticClassXXXX 的定义所有静态成员的类型。
一个叫做 StaticXXXX 的 StaticClassXXXX 的实例，用于静态成员。
Interfaces
TBD
Arrays
动态数组的组成为：
| offset | contents |
|---|
| 0 | array dimension |
| size_t | pointer to array data |
动态数组的声明：( 本文出处: http://www.d-programming-language-china.org )
静态数组的声明：
因此，静态数组总是静态的将大小作为型别本身的一部分，所以它的实现跟 C 中的实现相同。静态数组和动态数组之间可以轻松的相互转换。
Associative Arrays关联数组
Associative arrays consist of a pointer to an opaque, implementation defined type. The current implementation is contained in phobos/internal/aaA.d.
Reference Types引用型别
D 有引用型别，但是它们是隐式的。例如，类总是通过引用访问的；这意味着类的实例决不会位于堆栈上或者作为函数参数被传递。
当给函数传递一个静态数组时，将会隐式的把它转化为静态数组的引用。例如：
当将 abc 传递给函数时，会造成下面的隐式转换：( 本文出处: http://www.d-programming-language-china.org )
void func(int[3] array); // actually <reference to><array[3] of><int>
void func(int* p); // abc is converted to a pointer
// to the first element
void func(int[] array); // abc is converted to a dynamic array
Name Mangling
D accomplishes typesafe linking by mangling a D identifier to include scope and type information.
MangledName:
_D QualifiedName Type
_D QualifiedName M Type
QualifiedName:
SymbolName
SymbolName QualifiedName
SymbolName:
LName
TemplateInstanceName
The M means that the symbol is a function that requires a this pointer.
Template Instance Names have the types and values of its parameters encoded into it:
TemplateInstanceName:
__T LName TemplateArgs Z
TemplateArgs:
TemplateArg
TemplateArg TemplateArgs
TemplateArg:
T Type
V Type Value
S LName
Value:
n
Number
N Number
e HexFloat
c HexFloat c HexFloat
A Number Value...
HexFloat:
NAN
INF
NINF
N HexDigits P Exponent
HexDigits P Exponent
Exponent:
N Number
Number
HexDigits:
HexDigit
HexDigit HexDigits
HexDigit:
Digit
A
B
C
D
E
F
n
is for null arguments.
Number
is for positive numeric literals (including character literals).
N Number
is for negative numeric literals.
e HexFloat
is for real and imaginary floating point literals.
c HexFloat c HexFloat
is for complex floating point literals.
Width Number _ HexDigits
Width is whether the characters are 1 byte (a), 2 bytes (w) or 4 bytes (d) in size. Number is the number of characters in the string. The HexDigits are the hex data for the string.
A Number Value...
An array literal. Value is repeated Number times.
Name:
Namestart
Namestart Namechars
Namestart:
_
Alpha
Namechar:
Namestart
Digit
Namechars:
Namechar
Namechar Namechars
A Name is a standard D identifier.( 本文出处: http://www.d-programming-language-china.org )
LName:
Number Name
Number:
Digit
Digit Number
Digit:
0
1
2
3
4
5
6
7
8
9
An LName is a name preceded by a Number giving the number of characters in the Name.
Type Mangling
Types are mangled using a simple linear scheme:
Type:
TypeArray
TypeSarray
TypeAarray
TypePointer
TypeFunction
TypeIdent
TypeClass
TypeStruct
TypeEnum
TypeTypedef
TypeDelegate
TypeNone
TypeVoid
TypeByte
TypeUbyte
TypeShort
TypeUshort
TypeInt
TypeUint
TypeLong
TypeUlong
TypeFloat
TypeDouble
TypeReal
TypeIfloat
TypeIdouble
TypeIreal
TypeCfloat
TypeCdouble
TypeCreal
TypeBool
TypeChar
TypeWchar
TypeDchar
TypeTuple
TypeArray:
A Type
TypeSarray:
G Number Type
TypeAarray:
H Type Type
TypePointer:
P Type
TypeFunction:
CallConvention Arguments ArgClose Type
CallConvention:
F
U
W
V
R
Arguments:
Argument
Argument Arguments
Argument:
Type
J Type
K Type
L Type
ArgClose
X
Y
Z
TypeIdent:
I LName
TypeClass:
C LName
TypeStruct:
S LName
TypeEnum:
E LName
TypeTypedef:
T LName
TypeDelegate:
D TypeFunction
TypeNone:
n
TypeVoid:
v
TypeByte:
g
TypeUbyte:
h
TypeShort:
s
TypeUshort:
t
TypeInt:
i
TypeUint:
k
TypeLong:
l
TypeUlong:
m
TypeFloat:
f
TypeDouble:
d
TypeReal:
e
TypeIfloat:
o
TypeIdouble:
p
TypeIreal:
j
TypeCfloat:
q
TypeCdouble:
r
TypeCreal:
c
TypeBool:
b
TypeChar:
a
TypeWchar:
u
TypeDchar:
w
TypeTuple:
B Number Arguments
Function Calling Conventions函数调用约定
The extern (C) calling convention matches the C calling convention used by the supported C compiler on the host system. The extern (D) calling convention for x86 is described here.
1 Register Conventions
EAX, ECX, EDX are scratch registers and can be destroyed by a function.
EBX, ESI, EDI, EBP must be preserved across function calls.
EFLAGS is assumed destroyed across function calls, except for the direction flag which must be forward.
The FPU stack must be empty when calling a function.
The FPU control word must be preserved across function calls.
Floating point return values are returned on the FPU stack. These must be cleaned off by the caller, even if they are not used.
2 Return Value
The types bool, byte, ubyte, short, ushort, int, uint, pointer, Object, and interfaces are returned in EAX.
long and ulong are returned in EDX,EAX, where EDX gets the most significant half.
float, double, real, ifloat, idouble, ireal are returned in ST0.
cfloat, cdouble, creal are returned in ST1,ST0 where ST1 is the real part and ST0 is the imaginary part.
Dynamic arrays are returned with the pointer in EDX and the length in EAX.
Associative arrays are returned in EAX with garbage returned in EDX. The EDX value will probably be removed in the future; it's there for backwards compatibility with an earlier implementation of AA's.
Delegates are returned with the pointer to the function in EDX and the context pointer in EAX.
For Windows, 1, 2 and 4 byte structs are returned in EAX.
For Windows, 8 byte structs are returned in EDX,EAX, where EDX gets the most significant half.
For other struct sizes, and for all structs on Linux, the return value is stored through a hidden pointer passed as an argument to the function.
Constructors return the this pointer in EAX.( 本文出处: http://www.d-programming-language-china.org )
3 Parameters
The parameters to the non-variadic function:
are passed as follows:
a1
a2
...
an
hidden
this( 本文出处: http://www.d-programming-language-china.org )
where hidden is present if needed to return a struct value, and this is present if needed as the this pointer for a member function or the context pointer for a nested function.
The last parameter is passed in EAX rather than being pushed on the stack if the following conditions are met:( 本文出处: http://www.d-programming-language-china.org )
It fits in EAX.
It is not a 3 byte struct.
It is not a floating point type.
Parameters are always pushed as multiples of 4 bytes, rounding upwards, so the stack is always aligned on 4 byte boundaries. They are pushed most significant first. out and ref are passed as pointers. Static arrays are passed as pointers to their first element. On Windows, a real is pushed as a 10 byte quantity, a creal is pushed as a 20 byte quantity. On Linux, a real is pushed as a 12 byte quantity, a creal is pushed as two 12 byte quantities. The extra two bytes of pad occupy the 'most significant' position.
The callee cleans the stack.
The parameters to the variadic function:
void foo(int p1, int p2, int[] p3...)
foo(a1, a2, ..., an);
are passed as follows:
p1
p2
a3
hidden
this( 本文出处: http://www.d-programming-language-china.org )
The variadic part is converted to a dynamic array and the rest is the same as for non-variadic functions.
The parameters to the variadic function:
void foo(int p1, int p2, ...)
foo(a1, a2, a3, ..., an);
are passed as follows:
an
...
a3
a2
a1
_arguments
hidden
this
The caller is expected to clean the stack. _argptr is not passed, it is computed by the callee.( 本文出处: http://www.d-programming-language-china.org )
Exception Handling异常处理
1 Windows
Conforms to the Microsoft Windows Structured Exception Handling conventions.
2 Linux
Uses static address range/handler tables. TBD
Garbage Collection
The interface to this is found in phobos/internal/gc.
Runtime Helper Functions运行时辅助函数
These are found in phobos/internal.
Module Initialization and Termination模块初始化和终止
TBD
Unit Testing单元测试
TBD
Symbolic Debugging
D has types that are not represented in existing C or C++ debuggers. These are dynamic arrays, associative arrays, and delegates. Representing these types as structs causes problems because function calling conventions for structs are often different than that for these types, which causes C/C++ debuggers to misrepresent things. For these debuggers, they are represented as a C type which does match the calling conventions for the type. The dmd compiler will generate only C symbolic type info with the -gc compiler switch.
Types for C Debuggers | D type | C representation |
| dynamic array | unsigned long long |
| associative array | void* |
| delegate | long long |
For debuggers that can be modified to accept new types, the following extensions help them fully support the types.
Codeview Debugger Extensions
D makes use of the Codeview OEM generic type record indicated by LF_OEM (0x0015). The format is:
Codeview OEM Extensions for D | field size | 2 | 2 | 2 | 2 | 2 | 2 |
| D Type | Leaf Index | OEM Identifier | recOEM | num indices | type index | type index |
| dynamic array | LF_OEM | OEM | 1 | 2 | @index | @element |
| associative array | LF_OEM | OEM | 2 | 2 | @key | @element |
| delegate | LF_OEM | OEM | 3 | 2 | @this | @function |
OEM 0x42
index type index of array index
key type index of key
element type index of array element
this type index of context pointer
function type index of function( 本文出处: http://www.d-programming-language-china.org )
These extensions can be pretty-printed by obj2asm.
The Ddbg debugger supports them.
Dwarf Debugger Extensions
The following leaf types are added:
Dwarf Extensions for D | D type | Identifier | Value | Format |
| dynamic array | DW_TAG_darray_type | 0x41 | DW_AT_type is element type |
| associative array | DW_TAG_aarray_type | 0x42 | DW_AT_type, is element type, DW_AT_containing_type key type |
| delegate | DW_TAG_delegate_type | 0x43 | DW_AT_type, is function type, DW_AT_containing_type is 'this' type |
These extensions can be pretty-printed by dumpobj.
http://www.digitalmars.com/ctg/dumpobj.html( 本文出处: http://www.d-programming-language-china.org )
The ZeroBUGS debugger supports them.
http://www.zerobugs.org/
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