This document provides usage information about the LLVM makefile system. While loosely patterned after the BSD makefile system, LLVM has taken a departure from BSD in order to implement additional features needed by LLVM. @@ -99,20 +99,19 @@
The LLVM Makefile System is the component of LLVM that is responsible for building the software, testing it, generating distributions, checking those distributions, installing and uninstalling, etc. It consists of a several files throughout the source tree. These files and other general concepts are described in this section.
-The LLVM Makefile System is quite generous. It not only builds its own software, but it can build yours too. Built into the system is knowledge of the llvm/projects directory. Any directory under projects @@ -129,8 +128,8 @@
To use the makefile system, you simply create a file named Makefile in your directory and declare values for certain variables. The variables and values that you select determine what the makefile system @@ -139,16 +138,15 @@
Setting variables alone is not enough. You must include into your Makefile additional files that provide the rules of the LLVM Makefile system. The various files involved are described in the sections that follow.
-Each directory to participate in the build needs to have a file named Makefile. This is the file first read by make. It has three sections:
@@ -163,9 +161,8 @@Every project must have a Makefile.common file at its top source directory. This file serves three purposes:
Every project must have a Makefile.config at the top of its build directory. This file is generated by the configure script from the pattern provided by the @@ -196,8 +192,8 @@
This file, located at $(LLVM_SRC_ROOT)/Makefile.rules is the heart of the LLVM Makefile System. It provides all the logic, dependencies, and rules for building the targets supported by the system. What it does largely @@ -205,9 +201,11 @@ have been set before Makefile.rules is included.
User Makefiles need not have comments in them unless the construction is unusual or it does not strictly follow the rules and patterns of the LLVM makefile system. Makefile comments are invoked with the pound (#) character. @@ -215,19 +213,20 @@ by make.
This section provides some examples of the different kinds of modules you can build with the LLVM makefile system. In general, each directory you provide will build a single object although that object may be composed of additionally compiled components.
-Only a few variable definitions are needed to build a regular library. Normally, the makefile system will build all the software into a single libname.o (pre-linked) object. This means the library is not @@ -256,11 +255,10 @@ -load option. See the WritingAnLLVMPass.html document for an example of why you might want to do this. -
In some situations, it is desirable to build a single bitcode module from a variety of sources, instead of an archive, shared library, or bitcode library. Bitcode modules can be specified in addition to any of the other @@ -280,10 +278,10 @@
In some situations, you need to create a loadable module. Loadable modules can be loaded into programs like opt or llc to specify additional passes to run or targets to support. Loadable modules are also @@ -311,9 +309,11 @@ library which is part of lib/System implementation.
For building executable programs (tools), you must provide the name of the tool and the names of the libraries you wish to link with the tool. For example:
@@ -344,11 +344,10 @@ syntax is used. Note that in order to use the .a suffix, the library in question must have been built with the ARCHIVE_LIBRARY option set. -Many tools will want to use the JIT features of LLVM. To do this, you simply specify that you want an execution 'engine', and the makefiles will automatically link in the appropriate JIT for the host or an interpreter @@ -367,11 +366,15 @@
This section describes each of the targets that can be built using the LLVM Makefile system. Any target can be invoked from any directory but not all are applicable to a given directory (e.g. "check", "dist" and "install" will @@ -426,11 +429,10 @@
When you invoke make with no arguments, you are implicitly instructing it to seek the "all" target (goal). This target is used for building the software recursively and will do different things in different @@ -440,15 +442,15 @@
This target is the same as all but it operates only on the current directory instead of recursively.
This target can be invoked from anywhere within a project's directories but always invokes the check-local target in the project's test directory, if it exists and has a @@ -464,8 +466,8 @@
This target should be implemented by the Makefile in the project's test directory. It is invoked by the check target elsewhere. Each project is free to define the actions of check-local as @@ -475,8 +477,8 @@
This target cleans the build directory, recursively removing all things that the Makefile builds. The cleaning rules have been made guarded so they shouldn't go awry (via rm -f $(UNSET_VARIABLE)/* which will attempt @@ -484,15 +486,15 @@
This target does the same thing as clean but only for the current (local) directory.
This target builds a distribution tarball. It first builds the entire project using the all target and then tars up the necessary files and compresses it. The generated tarball is sufficient for a casual source @@ -500,8 +502,8 @@
This target does the same thing as the dist target but also checks the distribution tarball. The check is made by unpacking the tarball to a new directory, configuring it, building it, installing it, and then verifying that @@ -512,16 +514,16 @@
This is a special form of the clean clean target. It performs a normal clean but also removes things pertaining to building the distribution.
This target finalizes shared objects and executables and copies all libraries, headers, executables and documentation to the directory given with the --prefix option to configure. When completed, @@ -538,8 +540,8 @@
This utility target checks to see if the Makefile in the object directory is older than the Makefile in the source directory and copies it if so. It also reruns the configure script if that needs to @@ -549,15 +551,15 @@
This utility target just causes the LLVM makefiles to print out some of the makefile variables so that you can double check how things are set.
This utility target will force a reconfigure of LLVM or your project. It simply runs $(PROJ_OBJ_ROOT)/config.status --recheck to rerun the configuration tests and rebuild the configured files. This isn't generally @@ -566,8 +568,8 @@
This utility target, only available when $(PROJ_OBJ_ROOT) is not the same as $(PROJ_SRC_ROOT), will completely clean the $(PROJ_OBJ_ROOT) directory by removing its content entirely and @@ -578,8 +580,8 @@
This target will generate a TAGS file in the top-level source directory. It is meant for use with emacs, XEmacs, or ViM. The TAGS file provides an index of symbol definitions so that the editor can jump you to the @@ -587,18 +589,20 @@
This target is the opposite of the install target. It removes the header, library and executable files from the installation directories. Note that the directories themselves are not removed because it is not guaranteed that LLVM is the only thing installing there (e.g. --prefix=/usr).
Variables are used to tell the LLVM Makefile System what to do and to obtain information from it. Variables are also used internally by the LLVM Makefile System. Variable names that contain only the upper case alphabetic @@ -606,11 +610,10 @@ variables are internal to the LLVM Makefile System and should not be relied upon nor modified. The sections below describe how to use the LLVM Makefile variables.
-Variables listed in the table below should be set before the inclusion of $(LEVEL)/Makefile.common. These variables provide input to the LLVM make system that tell it what to do @@ -640,18 +643,18 @@ generate dependencies when running the compiler. Use of this feature is discouraged and it may be removed at a later date.
Override variables can be used to override the default values provided by the LLVM makefile system. These variables can be set in several ways:
@@ -785,6 +788,9 @@ not.Variables listed in the table below can be used by the user's Makefile but should not be changed. Changing the value will generally cause the build to go wrong, so don't do it.
@@ -936,8 +942,8 @@Variables listed below are used by the LLVM Makefile System and considered internal. You should not use these variables under any circumstances.
@@ -1015,6 +1021,8 @@