scons: Make LLVM a black-white dependency.

Now that draw depends on llvm it is very difficult to correctly handle
broken llvm installations. Either the user requests LLVM and it needs to
supply a working installation. Or it doesn't, and it gets no LLVM
accelerate pipe drivers.

SConstruct

@@ -81,15 +81,6 @@ debug = env['debug']
 dri = env['dri']
 machine = env['machine']
 platform = env['platform']
-drawllvm = 'llvmpipe' in env['drivers']
-
-# LLVM support in the Draw module
-if drawllvm:
-        env.Tool('llvm')
-        if not env.has_key('LLVM_VERSION'):
-           drawllvm = False
-if drawllvm:
-        env.Append(CFLAGS = ['-DDRAW_LLVM=1'])
 
 # derived options
 x86 = machine == 'x86'
@@ -102,7 +93,6 @@ Export([
 	'x86', 
 	'ppc', 
 	'dri', 
-	'drawllvm',
 	'platform',
 	'gcc',
 	'msvc',
@@ -167,10 +157,6 @@ if platform in ('posix', 'linux', 'freebsd', 'darwin'):
 		'dl',
 	])
 
-# LLVM support in the Draw module
-if drawllvm:
-    env.Append(CPPDEFINES = ['DRAW_LLVM'])
-
 # for debugging
 #print env.Dump()
 

common.py

@@ -3,6 +3,7 @@
 
 import os
 import os.path
+import subprocess
 import sys
 import platform as _platform
 
@@ -33,6 +34,11 @@ else:
 	default_machine = _platform.machine()
 default_machine = _machine_map.get(default_machine, 'generic')
 
+if 'LLVM' in os.environ or subprocess.call(['llvm-config', '--version'], stdout=subprocess.PIPE) == 0:
+    default_llvm = 'yes'
+else:
+    default_llvm = 'no'
+
 if default_platform in ('linux', 'freebsd'):
 	default_dri = 'yes'
 elif default_platform in ('winddk', 'windows', 'wince', 'darwin'):
@@ -61,5 +67,5 @@ def AddOptions(opts):
 	opts.Add(EnumOption('platform', 'target platform', default_platform,
 											 allowed_values=('linux', 'cell', 'windows', 'winddk', 'wince', 'darwin', 'embedded')))
 	opts.Add('toolchain', 'compiler toolchain', 'default')
-	opts.Add(BoolOption('llvm', 'use LLVM', 'no'))
+	opts.Add(BoolOption('llvm', 'use LLVM', default_llvm))
 	opts.Add(BoolOption('dri', 'build DRI drivers', default_dri))

configs/linux-llvm

@@ -12,7 +12,7 @@ GALLIUM_DRIVERS_DIRS += llvmpipe
 OPT_FLAGS = -O3 -ansi -pedantic
 ARCH_FLAGS = -mmmx -msse -msse2 -mstackrealign
 
-DEFINES += -DNDEBUG -DGALLIUM_LLVMPIPE -DDRAW_LLVM -DHAVE_UDIS86
+DEFINES += -DNDEBUG -DGALLIUM_LLVMPIPE -DHAVE_UDIS86
 
 # override -std=c99
 CFLAGS += -std=gnu99

scons/gallium.py

@@ -142,8 +142,6 @@ def generate(env):
     # configuration. See also http://www.scons.org/wiki/AdvancedBuildExample
     build_topdir = 'build'
     build_subdir = env['platform']
-    if env['llvm']:
-        build_subdir += "-llvm"
     if env['machine'] != 'generic':
         build_subdir += '-' + env['machine']
     if env['debug']:
@@ -471,6 +469,10 @@ def generate(env):
     # Default libs
     env.Append(LIBS = [])
 
+    # Load LLVM
+    if env['llvm']:
+        env.Tool('llvm')
+
     # Custom builders and methods
     env.Tool('custom')
     createInstallMethods(env)

scons/llvm.py

@@ -63,13 +63,14 @@ def generate(env):
     if env['platform'] == 'windows':
         # XXX: There is no llvm-config on Windows, so assume a standard layout
         if llvm_dir is None:
-            return
+            print 'scons: LLVM environment variable must be specified when building for windows'
+            env.Exit(1)
 
         # Try to determine the LLVM version from llvm/Config/config.h
         llvm_config = os.path.join(llvm_dir, 'include/llvm/Config/config.h')
         if not os.path.exists(llvm_config):
             print 'scons: could not find %s' % llvm_config
-            return
+            env.Exit(1)
         llvm_version_re = re.compile(r'^#define PACKAGE_VERSION "([^"]*)"')
         llvm_version = None
         for line in open(llvm_config, 'rt'):
@@ -80,7 +81,7 @@ def generate(env):
                 break
         if llvm_version is None:
             print 'scons: could not determine the LLVM version from %s' % llvm_config
-            return
+            env.Exit(1)
 
         env.Prepend(CPPPATH = [os.path.join(llvm_dir, 'include')])
         env.AppendUnique(CPPDEFINES = [
@@ -129,7 +130,11 @@ def generate(env):
                 # debug build we'll be linking against LIBCMTD, so disable
                 # that.
                 env.Append(LINKFLAGS = ['/nodefaultlib:LIBCMT'])
-    elif env.Detect('llvm-config'):
+    else:
+        if not env.Detect('llvm-config'):
+            print 'scons: llvm-config script not found' % llvm_version
+            env.Exit(1)
+
         llvm_version = env.backtick('llvm-config --version').rstrip()
         llvm_version = distutils.version.LooseVersion(llvm_version)
 
@@ -138,11 +143,10 @@ def generate(env):
             env.ParseConfig('llvm-config --libs jit interpreter nativecodegen bitwriter')
             env.ParseConfig('llvm-config --ldflags')
         except OSError:
-            print 'llvm-config version %s failed' % llvm_version
+            print 'scons: llvm-config version %s failed' % llvm_version
+            env.Exit(1)
         else:
             env['LINK'] = env['CXX']
-    else:
-        return
 
     assert llvm_version is not None
 

src/gallium/auxiliary/SConscript

@@ -191,7 +191,7 @@ source = [
     'target-helpers/wrap_screen.c',
 ]
 
-if drawllvm:
+if env['llvm']:
     source += [
     'gallivm/lp_bld_alpha.c',
     'gallivm/lp_bld_arit.c',

src/gallium/auxiliary/draw/draw_context.h

@@ -196,7 +196,7 @@ boolean draw_need_pipeline(const struct draw_context *draw,
                            const struct pipe_rasterizer_state *rasterizer,
                            unsigned prim );
 
-#ifdef DRAW_LLVM
+#ifdef HAVE_LLVM
 /*******************************************************************************
  * LLVM integration
  */

src/gallium/auxiliary/draw/draw_llvm.h

@@ -1,5 +1,5 @@
-#ifndef DRAW_LLVM_H
-#define DRAW_LLVM_H
+#ifndef HAVE_LLVM_H
+#define HAVE_LLVM_H
 
 #include "draw/draw_private.h"
 

src/gallium/auxiliary/draw/draw_private.h

@@ -46,7 +46,7 @@
 
 #include "tgsi/tgsi_scan.h"
 
-#ifdef DRAW_LLVM
+#ifdef HAVE_LLVM
 #include <llvm-c/ExecutionEngine.h>
 #endif
 
@@ -241,7 +241,7 @@ struct draw_context
 
    unsigned instance_id;
 
-#ifdef DRAW_LLVM
+#ifdef HAVE_LLVM
    LLVMExecutionEngineRef engine;
 #endif
    void *driver_private;

src/gallium/auxiliary/draw/draw_pt.c

@@ -140,7 +140,7 @@ boolean draw_pt_init( struct draw_context *draw )
    if (!draw->pt.middle.fetch_shade_emit)
       return FALSE;
 
-#if DRAW_LLVM
+#if HAVE_LLVM
    draw->pt.middle.general = draw_pt_fetch_pipeline_or_emit_llvm( draw );
 #else
    draw->pt.middle.general = NULL;

src/gallium/auxiliary/draw/draw_vs_llvm.c

@@ -40,7 +40,7 @@
 
 #include "tgsi/tgsi_parse.h"
 
-#ifdef DRAW_LLVM
+#ifdef HAVE_LLVM
 
 struct draw_llvm_vertex_shader {
    struct draw_vertex_shader base;

src/gallium/auxiliary/gallivm/lp_bld.h

@@ -38,9 +38,9 @@
 #include <llvm-c/Core.h>  
 
 
-/** Set version to 0 if missing to avoid #ifdef HAVE_LLVM everywhere */
+/** Ensure HAVE_LLVM is set to avoid #ifdef HAVE_LLVM everywhere */
 #ifndef HAVE_LLVM
-#define HAVE_LLVM 0x0207
+#error "HAVE_LLVM should be set with LLVM's version number, e.g. (0x0207 for 2.7)"
 #endif
 
 

src/gallium/drivers/llvmpipe/SConscript

@@ -1,12 +1,11 @@
 Import('*')
 
-env = env.Clone()
-
-env.Tool('llvm')
-if not env.has_key('LLVM_VERSION'):
-    print 'warning: LLVM not found: not building llvmpipe'
+if not env['llvm']:
+    print 'warning: LLVM disabled: not building llvmpipe'
     Return()
 
+env = env.Clone()
+
 env.Tool('udis86')
 
 env.Append(CPPPATH = ['.'])

src/gallium/drivers/sw/SConscript

@@ -23,11 +23,9 @@ if 'softpipe' in env['drivers']:
     env.Prepend(LIBS = [softpipe])
 
 if 'llvmpipe' in env['drivers']:
-    env.Tool('llvm')
-    if 'LLVM_VERSION' in env:
-        env.Append(CPPDEFINES = 'GALLIUM_LLVMPIPE')
-        env.Tool('udis86')
-        env.Prepend(LIBS = [llvmpipe])
+    env.Append(CPPDEFINES = 'GALLIUM_LLVMPIPE')
+    env.Tool('udis86')
+    env.Prepend(LIBS = [llvmpipe])
     
 if 'cell' in env['drivers']:
     env.Append(CPPDEFINES = 'GALLIUM_CELL')

src/gallium/state_trackers/python/SConscript

@@ -46,7 +46,6 @@ if 'python' in env['statetrackers']:
 
     if 'llvmpipe' in env['drivers']:
         env.Append(CPPDEFINES = ['HAVE_LLVMPIPE'])
-        env.Tool('llvm')
         env.Prepend(LIBS = [llvmpipe])
     if 'softpipe' in env['drivers']:
         env.Append(CPPDEFINES = ['HAVE_SOFTPIPE'])

src/gallium/targets/dri-swrast/SConscript

@@ -25,11 +25,9 @@ if 'softpipe' in env['drivers']:
     env.Prepend(LIBS = [softpipe])
 
 if 'llvmpipe' in env['drivers']:
-    env.Tool('llvm')
-    if 'LLVM_VERSION' in env:
-        env.Append(CPPDEFINES = 'GALLIUM_LLVMPIPE')
-        env.Tool('udis86')
-        env.Prepend(LIBS = [llvmpipe])
+    env.Append(CPPDEFINES = 'GALLIUM_LLVMPIPE')
+    env.Tool('udis86')
+    env.Prepend(LIBS = [llvmpipe])
 
 swrastg_sources = [
     'swrast_drm_api.c'

src/gallium/targets/graw-xlib/SConscript

@@ -33,11 +33,9 @@ if 'softpipe' in env['drivers']:
     env.Prepend(LIBS = [softpipe])
 
 if 'llvmpipe' in env['drivers']:
-    env.Tool('llvm')
-    if 'LLVM_VERSION' in env:
-        env.Append(CPPDEFINES = 'GALLIUM_LLVMPIPE')
-        env.Tool('udis86')
-        env.Prepend(LIBS = [llvmpipe])
+    env.Append(CPPDEFINES = 'GALLIUM_LLVMPIPE')
+    env.Tool('udis86')
+    env.Prepend(LIBS = [llvmpipe])
 
 # Need this for trace, identity drivers referenced by
 # gallium_wrap_screen().

src/gallium/targets/libgl-gdi/SConscript

@@ -27,10 +27,8 @@ if env['platform'] == 'windows':
         drivers = [softpipe]
 
     if 'llvmpipe' in env['drivers']:
-        env.Tool('llvm')
-        if 'LLVM_VERSION' in env:
-            sources = ['gdi_llvmpipe_winsys.c']
-            drivers = [llvmpipe]
+        sources = ['gdi_llvmpipe_winsys.c']
+        drivers = [llvmpipe]
 
     if not sources or not drivers:
         print 'warning: softpipe or llvmpipe not selected, gdi winsys disabled'

src/gallium/targets/libgl-xlib/SConscript

@@ -50,11 +50,9 @@ if 'softpipe' in env['drivers']:
     env.Prepend(LIBS = [softpipe])
 
 if 'llvmpipe' in env['drivers']:
-    env.Tool('llvm')
-    if 'LLVM_VERSION' in env:
-        env.Append(CPPDEFINES = 'GALLIUM_LLVMPIPE')
-        env.Tool('udis86')
-        env.Prepend(LIBS = [llvmpipe])
+    env.Append(CPPDEFINES = 'GALLIUM_LLVMPIPE')
+    env.Tool('udis86')
+    env.Prepend(LIBS = [llvmpipe])
     
 if 'cell' in env['drivers']:
     env.Append(CPPDEFINES = 'GALLIUM_CELL')