From 2c45228651bc3bfbec214343f6896841c3cb1d04 Mon Sep 17 00:00:00 2001 From: Reid Spencer Date: Tue, 7 Aug 2007 14:34:28 +0000 Subject: [PATCH] Describe the global/local naming convention. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40890 91177308-0d34-0410-b5e6-96231b3b80d8 --- docs/LangRef.html | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/docs/LangRef.html b/docs/LangRef.html index 35990bdcdd9..bf9464bc7db 100644 --- a/docs/LangRef.html +++ b/docs/LangRef.html @@ -296,25 +296,27 @@ the parser.

-

LLVM uses three different forms of identifiers, for different -purposes:

+

LLVM identifiers come in two basic types: global and local. Global + identifiers (functions, global variables) begin with the @ character. Local + identifiers (register names, types) begin with the % character. Additionally, + there are three different formats for identifiers, for different purposes:

    -
  1. Named values are represented as a string of characters with a '%' prefix. - For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual - regular expression used is '%[a-zA-Z$._][a-zA-Z$._0-9]*'. +
  2. Named values are represented as a string of characters with their prefix. + For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual + regular expression used is '[%@][a-zA-Z$._][a-zA-Z$._0-9]*'. Identifiers which require other characters in their names can be surrounded - with quotes. In this way, anything except a " character can be used - in a name.
    3. + with quotes. In this way, anything except a " character can + be used in a named value. -
  3. Unnamed values are represented as an unsigned numeric value with a '%' - prefix. For example, %12, %2, %44.
    4. +
  4. Unnamed values are represented as an unsigned numeric value with their + prefix. For example, %12, @2, %44.
  5. Constants, which are described in a section about constants, below.
-

LLVM requires that values start with a '%' sign for two reasons: Compilers +

LLVM requires that values start with a prefix for two reasons: Compilers don't need to worry about name clashes with reserved words, and the set of reserved words may be expanded in the future without penalty. Additionally, unnamed identifiers allow a compiler to quickly come up with a temporary @@ -327,7 +329,7 @@ languages. There are keywords for different opcodes 'ret', etc...), for primitive type names ('void', 'i32', etc...), and others. These reserved words cannot conflict with variable names, because -none of them start with a '%' character.

+none of them start with a prefix character ('%' or '@').

Here is an example of LLVM code to multiply the integer variable '%X' by 8:

-- 2.34.1