崔添翼 § 翼若垂天之云

（本文是 http://llvm.org/releases/2.9/docs/LangRef.html 的阅读笔记，前作为《LLVM笔记(1)：LLVM的语言（上）》。）

• Type System
• Type Classifications
• integer: i1, i2, i3, … i8, … i16, … i32, … i64
• floating point: float, double, x86_fp80, fp128, ppc_fp128
• first class: integer, floating point, pointer, vector, structure, array, label, metadata.
• primitive: label, void, integer, floating point, x86mmx, metadata.
• derived: array, function, pointer, structure, packed structure, vector, opaque.
• Array type

• [<# elements> x <elementtype>]

• Function Type

• <returntype> (<parameter list>)

• Structure Type

• { <type list> }

• Packed Structure Type

• < { <type list> } >

• Pointer Type

• <type> *

• Vector Type

• < <# elements> x <elementtype> >

• Opaque Type: represents unknown type
• Type Up-references
• needed by the asmprinter for printing out cyclic types
• Constants
• Simple Constants
• Boolean(true, false)
• Integer(e.g. 42)
• Floating point(3.14 or 6.02E+23 or double 0x432ff973cafa8000 (IEEE))
• Null pointer (null)
• Complex Constants
• Structure constants
• { i32 4, float 17.0, i32* @G }
• @G = external global i32
• Array constants
• [ i32 42, i32 11, i32 74 ]
• Vector constants
• [ i32 42, i32 11, i32 74 ]
• Zero initialization
• zeroinitializer
• Metadata node
• metadata !{ i32 0, metadata !”test” }
• Global Variable and Function Addresses
• Undefined Values
• The string ‘undef’ can be used anywhere a constant is expected, and indicates that the user of the value may receive an unspecified bit-pattern.
• Trap Values
• Addresses of Basic Blocks
• blockaddress(@function, %block)
• Constant Expressions
• trunc, zext, sext, fptrunc, fpext, fptoui, fptosi, uitofp, sitofp, ptrtoint, inttoptr, bitcast
• getelementptr, select, icmp, fcmp, extractelement, insertelement, shufflevector, extractvalue, insertvalue
• OPCODE
• Other Values
• Inline Assembler Expressions
• Inline Asm Metadata
• Metadata Nodes and Metadata Strings
• Intrinsic Global Variables
• The ‘llvm.used’ Global Variable
• The @llvm.used global is an array with i8* element type which has appending linkage.
• The ‘llvm.compiler.used’ Global Variable
• The ‘llvm.global_ctors’ Global Variable
• The ‘llvm.global_dtors’ Global Variable