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Peter Collingbourne 5b721561aa DI: Reverse direction of subprogram -> function edge. Previously, subprograms contained a metadata reference to the function they described. Because most clients need to get or set a subprogram for a given function rather than the other way around, this created unneeded inefficiency. For example, many passes needed to call the function llvm::makeSubprogramMap() to build a mapping from functions to subprograms, and the IR linker needed to fix up function references in a way that caused quadratic complexity in the IR linking phase of LTO. This change reverses the direction of the edge by storing the subprogram as function-level metadata and removing DISubprogram's function field. Since this is an IR change, a bitcode upgrade has been provided. Fixes PR23367. An upgrade script for textual IR for out-of-tree clients is attached to the PR. Differential Revision: http://reviews.llvm.org/D14265 llvm-svn: 252219		2015-11-05 22:03:56 +00:00
..
llvm	DI: Reverse direction of subprogram -> function edge.	2015-11-05 22:03:56 +00:00
build.sh	Expose LLVM version string via macro in llvm-config.h, and modify Go bindings	2014-11-19 03:34:17 +00:00
conftest.go
README.txt

README.txt

This directory contains LLVM bindings for the Go programming language
(http://golang.org).

Prerequisites
-------------

* Go 1.2+.
* CMake (to build LLVM).

Using the bindings
------------------

The package path "llvm.org/llvm/bindings/go/llvm" can be used to
import the latest development version of LLVM from SVN. Paths such as
"llvm.org/llvm.v36/bindings/go/llvm" refer to released versions of LLVM.

It is recommended to use the "-d" flag with "go get" to download the
package or a dependency, as an additional step is required to build LLVM
(see "Building LLVM" below).

Building LLVM
-------------

The script "build.sh" in this directory can be used to build LLVM and prepare
it to be used by the bindings. If you receive an error message from "go build"
like this:

    ./analysis.go:4:84: fatal error: llvm-c/Analysis.h: No such file or directory
     #include <llvm-c/Analysis.h> // If you are getting an error here read bindings/go/README.txt

or like this:

    ./llvm_dep.go:5: undefined: run_build_sh

it means that LLVM needs to be built or updated by running the script.

    $ $GOPATH/src/llvm.org/llvm/bindings/go/build.sh

Any command line arguments supplied to the script are passed to LLVM's CMake
build system. A good set of arguments to use during development are:

    $ $GOPATH/src/llvm.org/llvm/bindings/go/build.sh -DCMAKE_BUILD_TYPE=Debug -DLLVM_TARGETS_TO_BUILD=host -DBUILD_SHARED_LIBS=ON

Note that CMake keeps a cache of build settings so once you have built
LLVM there is no need to pass these arguments again after updating.

Alternatively, you can build LLVM yourself, but you must then set the
CGO_CPPFLAGS, CGO_CXXFLAGS and CGO_LDFLAGS environment variables:

    $ export CGO_CPPFLAGS="`/path/to/llvm-build/bin/llvm-config --cppflags`"
    $ export CGO_CXXFLAGS=-std=c++11
    $ export CGO_LDFLAGS="`/path/to/llvm-build/bin/llvm-config --ldflags --libs --system-libs all`"
    $ go build -tags byollvm