LLVM Language Reference Manual. Abstract; Introduction. History of docs / @. The LLVM compiler infrastructure project is a “collection of modular and reusable compiler and .. For the full documentation, refer to ^ Stellard, Tom (March 26, ). “[LLVMdev] RFC: R, a new backend for.

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Identified types can be recursive, can be opaqued, and are never uniqued.

On targets that support it, this allows an intelligent linker to optimize references to the symbol without being impeded as it would be by llvm. If the cmpxchg is marked as volatilethen the optimizer is not allowed to modify the number or order of execution of this cmpxchg with other volatile operations.

Also, any loop should have at most one directive applied to it and a sequence of transformations built using followup-attributes. Variables that are identified as pangref a protector will be arranged on the stack such that they are adjacent to the stack protector guard.


An explicit alignment may be specified for a function. For example, the following is a legal LLVM file:. As SSA values, global variables define pointer values that are in scope i. Their fields are labelled, and can be specified in any order. The major differences to getelementptr indexing are:. Named values are represented as a string of characters with their prefix.

ULP is defined as follows:. Note The current implementation accepts the following C-like escapes: If this is not safe e. These contained type descriptors can either be struct type descriptors themselves or scalar type descriptors.


LLVM – Wikipedia

This can be useful for special purpose optimizations that want to look for these annotations. It can be applied to a parameter with pointer to pointer type or a pointer-sized alloca. Poison values have the same behavior as undef valueswith langrff additional effect that any instruction that has a dependence on a poison value has undefined behavior.

Some targets support embedding flags to the linker inside individual object files. It is also possible to use an indirect register labgref, but only on output e. The semantics of parallel loops in this case is the one with the strongest cross-iteration instruction ordering freedom: Llvn example, in C this holds for an l-value of volatile primitive type with native hardware support, but not necessarily for aggregate types.

It expresses the possible ranges the loaded value or the value returned by the called function at this call site is in.

Struct type descriptors are represented as MDNode s with an odd number of operands greater than 1. The size of value must be larger than the size of ty2. The original value at the location is returned.

If multiple parameter attributes are needed, they are space separated. The third operand is an index indicating the position at which to insert the value. The llgm is required to be a constant integer value. Arguments whose type is matched against another type do not.

This corresponds for example to the C notion of a forward declared structure. Named metadata is a collection of metadata. When the call site is reached, the argument allocation must have been the most recent stack allocation that is still live, or the behavior is undefined. This gives the compiler more freedom to optimize.


This is used to implement the GCC nested function address extension. The first operand type of a store similarly only indicates the size and alignment of the store.

When lvm the hexadecimal form, constants of types half, float, and double are represented using the digit form shown above which matches the IEEE representation for double ; half and float values must, however, be exactly representable as IEEE half and single precision, respectively. Constant expressions may be of any first class type and may involve any LLVM operation that does not have side effects e. They return a structure — the first element of which is the multiplication, and the second element of which is a bit specifying if the unsigned multiplication resulted in an overflow.

It is not a value, just a keyword. This is particularly useful on indirect calls; without this we may treat such calls as though the target is non-convergent. The current metadata format is very simple. Control transfers to the block specified langef the address argument.

Instead, metadata is added to the IR to describe a type system of a higher level language. There are three different types of constraints, which are distinguished by a prefix symbol in front of the constraint code: