Customizing LLVMC: Reference Manual
-| Author: | -Mikhail Glushenkov <foldr@codedegers.com> |
|---|
Introduction
LLVMC is a generic compiler driver, designed to be customizable and extensible. It plays the same role for LLVM as the gcc program does for GCC - LLVMC's job is essentially to transform a set of input @@ -31,36 +52,11 @@ abstract graph. The structure of this graph is completely determined by plugins, which can be either statically or dynamically linked. This makes it possible to easily adapt LLVMC for other purposes - for example, as a build tool for game resources.
-Because LLVMC employs TableGen [1] as its configuration language, you +
Because LLVMC employs TableGen as its configuration language, you need to be familiar with it to customize LLVMC.
-Compiling with LLVMC
+Compiling with LLVMC
LLVMC tries hard to be as compatible with gcc as possible, although there are some small differences. Most of the time, however, you shouldn't be able to notice them:
@@ -98,7 +94,7 @@ also possible to choose the work-in-progress -clang option.Predefined options
+Predefined options
LLVMC has some built-in options that can't be overridden in the configuration libraries:
-
@@ -121,7 +117,7 @@ their standard meaning.
Compiling LLVMC plugins
+Compiling LLVMC plugins
It's easiest to start working on your own LLVMC plugin by copying the skeleton project which lives under $LLVMC_DIR/plugins/Simple:
@@ -174,7 +170,7 @@ $ make BUILTIN_PLUGINS=""
Customizing LLVMC: the compilation graph
+Customizing LLVMC: the compilation graph
Each TableGen configuration file should include the common definitions:
@@ -242,7 +238,7 @@ debugging), run llvmcgsview installed for this to work properly.
Describing options
+Describing options
Command-line options that the plugin supports are defined by using an OptionList:
@@ -293,7 +289,7 @@ output.-External options
+External options
Sometimes, when linking several plugins together, one plugin needs to access options defined in some other plugin. Because of the way options are implemented, such options should be marked as @@ -308,7 +304,7 @@ for. Example:
Conditional evaluation
+Conditional evaluation
The 'case' construct is the main means by which programmability is achieved in LLVMC. It can be used to calculate edge weights, program actions and modify the shell commands to be executed. The 'case' @@ -386,7 +382,7 @@ one of its arguments returns true. Example:
Writing a tool description
+Writing a tool description
As was said earlier, nodes in the compilation graph represent tools, which are described separately. A tool definition looks like this (taken from the include/llvm/CompilerDriver/Tools.td file):
@@ -428,7 +424,7 @@ below).Actions
+Actions
A tool often needs to react to command-line options, and this is precisely what the actions property is for. The next example illustrates this feature:
@@ -486,7 +482,7 @@ Example: (unpack_valuesLanguage map
+Language map
If you are adding support for a new language to LLVMC, you'll need to modify the language map, which defines mappings from file extensions to language names. It is used to choose the proper toolchain(s) for a @@ -509,9 +505,9 @@ multiple output languages, for nodes "inside" the graph the input and output languages should match. This is enforced at compile-time.
More advanced topics
+More advanced topics
Hooks and environment variables
+Hooks and environment variables
Normally, LLVMC executes programs from the system PATH. Sometimes, this is not sufficient: for example, we may want to specify tool names in the configuration file. This can be achieved via the mechanism of @@ -539,7 +535,7 @@ the case expression (
How plugins are loaded
+How plugins are loaded
It is possible for LLVMC plugins to depend on each other. For example, one can create edges between nodes defined in some other plugin. To make this work, however, that plugin should be loaded first. To @@ -555,50 +551,27 @@ with 0. Therefore, the plugin with the highest priority value will be loaded last.
Debugging
+Debugging
When writing LLVMC plugins, it can be useful to get a visual view of the resulting compilation graph. This can be achieved via the command -line option --view-graph. This command assumes that Graphviz [2] and -Ghostview [3] are installed. There is also a --dump-graph option that -creates a Graphviz source file(compilation-graph.dot) in the +line option --view-graph. This command assumes that Graphviz and +Ghostview are installed. There is also a --dump-graph option that +creates a Graphviz source file (compilation-graph.dot) in the current directory.
-References
-| [1] | TableGen Fundamentals -http://llvm.cs.uiuc.edu/docs/TableGenFundamentals.html |
| [2] | Graphviz -http://www.graphviz.org/ |
| [3] | Ghostview -http://pages.cs.wisc.edu/~ghost/ |
-
-
+
+- LLVM Compiler Infrastructure
+Mikhail Glushenkov
+LLVM Compiler Infrastructure
- Last modified: $Date: 2008-12-11 11:34:48 -0600 (Thu, 11 Dec 2008) $ - +Last modified: $Date: 2008-12-11 11:34:48 -0600 (Thu, 11 Dec 2008) $ +
Tutorial - Using LLVMC
-| Author: | -Mikhail Glushenkov <foldr@codedegers.com> |
|---|
Introduction
LLVMC is a generic compiler driver, which plays the same role for LLVM as the gcc program does for GCC - the difference being that LLVMC is designed to be more adaptable and easier to customize. Most of LLVMC functionality is implemented via plugins, which can be loaded dynamically or compiled in. This tutorial describes the basic usage and configuration of LLVMC.
-Compiling with LLVMC
+Compiling with LLVMC
In general, LLVMC tries to be command-line compatible with gcc as much as possible, so most of the familiar options work:
@@ -47,8 +43,8 @@ commands are executed by using the llvmc --help output.
Using LLVMC to generate toolchain drivers
-LLVMC plugins are written mostly using TableGen [1], so you need to +
Using LLVMC to generate toolchain drivers
+LLVMC plugins are written mostly using TableGen, so you need to be familiar with it to get anything done.
Start by compiling plugins/Simple/Simple.td, which is a primitive wrapper for gcc:
@@ -102,29 +98,20 @@ and is used for deciding which toolchain corresponds to a given input file.To learn more about LLVMC customization, refer to the reference manual and plugin source code in the plugins directory.
-References
-| [1] | TableGen Fundamentals -http://llvm.cs.uiuc.edu/docs/TableGenFundamentals.html |
-
-
+
+- LLVM Compiler Infrastructure
+Mikhail Glushenkov
+LLVM Compiler Infrastructure
- Last modified: $Date: 2008-12-11 11:34:48 -0600 (Thu, 11 Dec 2008) $ - -