Merge pull request #148 from maleadt/tb/rm_build

Replace Pkg.build with runtime initialization.

Author: maleadt

deps/.gitignore

@@ -5,10 +5,86 @@ using Printf
 using Libdl
 
 
-const ext = joinpath(@__DIR__, "..", "deps", "ext.jl")
-isfile(ext) || error("LLVM.jl has not been built, please run Pkg.build(\"LLVM\").")
-include(ext)
-const libllvm = libllvm_path
+## discovery
+
+using Libdl
+
+VERSION >= v"0.7.0-DEV.2576" || error("This version of LLVM.jl requires Julia 0.7")
+
+let
+    # find LLVM library
+
+    libllvm_paths = filter(Libdl.dllist()) do lib
+        occursin("LLVM", basename(lib))
+    end
+    if isempty(libllvm_paths)
+        error("""
+            Cannot find the LLVM library loaded by Julia.
+            Please use a version of Julia that has been built with USE_LLVM_SHLIB=1 (like the official binaries).
+            If you are, please file an issue and attach the output of `Libdl.dllist()`.""")
+    end
+    if length(libllvm_paths) > 1
+        error("""
+            Multiple LLVM libraries loaded by Julia.
+            Please file an issue and attach the output of `Libdl.dllist()`.""")
+    end
+    global const libllvm = first(libllvm_paths)
+    Base.include_dependency(libllvm)
+
+    global const libllvm_version = Base.libllvm_version::VersionNumber
+
+    # figure out the supported targets by looking at initialization routines
+    lib = Libdl.dlopen(libllvm)
+    llvm_targets = [:AArch64, :AMDGPU, :ARC, :ARM, :AVR, :BPF, :Hexagon, :Lanai, :MSP430,
+                    :Mips, :NVPTX, :PowerPC, :RISCV, :Sparc, :SystemZ, :WebAssembly, :X86,
+                    :XCore]
+    @show global const libllvm_targets = filter(llvm_targets) do target
+        sym = Libdl.dlsym_e(lib, Symbol("LLVMInitialize$(target)Target"))
+        sym !== nothing
+    end
+    # TODO: figure out the name of the native target
+
+    @debug "Found LLVM v$libllvm_version at $libllvm with support for $(join(libllvm_targets, ", "))"
+
+
+    # find appropriate LLVM.jl wrapper
+
+    vercmp_match(a,b)  = a.major==b.major &&  a.minor==b.minor
+    vercmp_compat(a,b) = a.major>b.major  || (a.major==b.major && a.minor>=b.minor)
+
+    llvmjl_wrappers_path = joinpath(@__DIR__, "..", "lib")
+    Base.include_dependency(llvmjl_wrappers_path)
+
+    llvmjl_wrappers = filter(path->isdir(joinpath(llvmjl_wrappers_path, path)),
+                                   readdir(llvmjl_wrappers_path))
+    @assert !isempty(llvmjl_wrappers)
+
+    matching_wrappers = filter(wrapper->vercmp_match(libllvm_version,
+                                                     VersionNumber(wrapper)),
+                                    llvmjl_wrappers)
+    global const llvmjl_wrapper = if !isempty(matching_wrappers)
+        @assert length(matching_wrappers) == 1
+        matching_wrappers[1]
+    else
+        compatible_wrappers = filter(wrapper->vercmp_compat(libllvm_version,
+                                                            VersionNumber(wrapper)),
+                                    llvmjl_wrappers)
+        isempty(compatible_wrappers) && error("Could not find any compatible wrapper for LLVM $(libllvm_version)")
+        last(compatible_wrappers)
+    end
+
+    @debug "Using LLVM.jl wrapper for LLVM v$llvmjl_wrapper"
+
+
+    # backwards-compatible flags
+
+    global const libllvm_system = false
+
+    global const configured = true
+end
+
+
+## source code includes
 
 include("util/types.jl")
 
@@ -49,14 +125,19 @@ include("interop.jl")
 
 include("deprecated.jl")
 
+
+## initialization
+
 function __init__()
     libllvm_paths = filter(Libdl.dllist()) do lib
         occursin("LLVM", basename(lib))
     end
     if length(libllvm_paths) > 1
         # NOTE: this still allows switching to a non-USE_LLVM_SHLIB version, but
         #       there's no way to detect that since the new libLLVM is loaded before this...
-        error("LLVM.jl and Julia are using different LLVM libraries, please re-run Pkg.build(\"LLVM\").")
+        cachefile = Base.compilecache(Base.PkgId(LLVM))
+        rm(cachefile)
+        error("Your set-up changed, and LLVM.jl needs to be reconfigured. Please load the package again.")
     end
 
     _install_handlers()