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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One or more of the argument types or the result type can be overloaded to accept any integer type. This section describes how to read, write, and allocate memory in LLVM. This is what allows a programmer to represent arrays, functions, pointers, and other useful types. If there is a mismatch between the explicit or inferred section information for the variable declaration and its definition the resulting behavior is undefined.
It consists of a return type and a list of formal parameter types. This metadata can only be applied to loads of a pointer type. This implies that fptrunc cannot be used to make a no-op cast.
A pointer value is associated with the addresses associated with any value it is based on. As SSA values, global variables define pointer values that are in scope i. This loop is usually unrolled, meaning there is no such loop. An attribute group is a module-level object. These are documented here. This calling convention should not be used lightly but only for specific situations such as an alternative to the register pinning performance technique often used when implementing functional programming languages.
If the offsets have a different width from the pointer, they are sign-extended or truncated to the width of the pointer. The constraints must always be given in that order: A DIExpression attached to the intrinsic refines this address to produce a concrete location for the source variable.
LLVM Language Reference Manual — LLVM 8 documentation
If no name is given, the record is anonymous. Vector versions of said instructions are ill-typed as well. The table is not allowed to contain duplicate constant entries. For instance, loop fusion can make other transformations impossible.
Retrieved March 31, Because the block can have no predecessors, it also cannot have any PHI nodes.
Retrieved June 17, These examples show the crucial difference between an undefined value and undefined behavior. DILocation nodes represent source debug locations. For example, the following is a legal LLVM file:. Arrays and structs are langfef types. No derived types may be created from metadata except for function arguments. This will disable some optimizations that require precise layout information, but pangref also prevents those optimizations from introducing target specificity into the IR.
The variable entry contains a subset of the fields in a function summarysee the descriptions there. The assembler requires the exact decimal value of a floating-point constant. If not present, or if the alignment is set to zero, the alignment of the global is set by the target to whatever it feels convenient. The major differences to getelementptr indexing are:.
The LLVM code representation is designed to be used in three different forms: Pointer values are associated with address ranges according to the following rules:. Constant expressions are used to allow expressions involving other constants to be used as constants. The value produced is a copy of the operand with its sign bit flipped.
Executing this instruction transfers control to one of the successors in handlersif appropriate, or continues to unwind via the unwind label if present. LLVM provides intrinsics for a few important bit manipulation operations.
DIBasicType nodes represent primitive types, such as intbool and float. It is the responsibility of lzngref code emitter to ensure that the alignment information is correct. These blocks are internally concatenated by LLVM and treated as a single unit, but may be separated in the. A vector type is a simple derived type that represents a vector of elements.
Each basic block may optionally start with a label giving the basic block a symbol table entrycontains a list of instructions, and ends with a terminator instruction such as a branch or function return.
Named metadata is a collection of langeef. These intrinsics are provided by LLVM to expose special features that may only be implemented with code generator support. At compile-time, the code generator generates information to allow the runtime to find the pointer at GC safe points.
Taking the remainder of a division by zero is undefined behavior. The first type indexed into must be a pointer value, subsequent types can be arrays, vectors, and structs.