src/gallium/auxiliary/gallivm/lp_bld_init.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2009 VMware, Inc.
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
  22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28
  29 #include "pipe/p_config.h"
  30 #include "pipe/p_compiler.h"
  31 #include "util/u_cpu_detect.h"
  32 #include "util/u_debug.h"
  33 #include "util/u_memory.h"
  34 #include "util/simple_list.h"
  35 #include "os/os_time.h"
  36 #include "lp_bld.h"
  37 #include "lp_bld_debug.h"
  38 #include "lp_bld_misc.h"
  39 #include "lp_bld_init.h"
  40
  41 #include <llvm-c/Analysis.h>
  42 #include <llvm-c/Transforms/Scalar.h>
  43 #include <llvm-c/BitWriter.h>
  44
  45
  46 /* Only MCJIT is available as of LLVM SVN r216982 */
  47 #if HAVE_LLVM >= 0x0306
  48 #  define USE_MCJIT 1
  49 #elif defined(PIPE_ARCH_PPC_64) || defined(PIPE_ARCH_S390) || defined(PIPE_ARCH_ARM) || defined(PIPE_ARCH_AARCH64)
  50 #  define USE_MCJIT 1
  51 #else
  52 static bool USE_MCJIT = 0;
  53 #endif
  54
  55
  56 #ifdef DEBUG
  57 unsigned gallivm_debug = 0;
  58
  59 static const struct debug_named_value lp_bld_debug_flags[] = {
  60    { "tgsi",   GALLIVM_DEBUG_TGSI, NULL },
  61    { "ir",     GALLIVM_DEBUG_IR, NULL },
  62    { "asm",    GALLIVM_DEBUG_ASM, NULL },
  63    { "nopt",   GALLIVM_DEBUG_NO_OPT, NULL },
  64    { "perf",   GALLIVM_DEBUG_PERF, NULL },
  65    { "no_brilinear", GALLIVM_DEBUG_NO_BRILINEAR, NULL },
  66    { "no_rho_approx", GALLIVM_DEBUG_NO_RHO_APPROX, NULL },
  67    { "no_quad_lod", GALLIVM_DEBUG_NO_QUAD_LOD, NULL },
  68    { "gc",     GALLIVM_DEBUG_GC, NULL },
  69    { "dumpbc", GALLIVM_DEBUG_DUMP_BC, NULL },
  70    DEBUG_NAMED_VALUE_END
  71 };
  72
  73 DEBUG_GET_ONCE_FLAGS_OPTION(gallivm_debug, "GALLIVM_DEBUG", lp_bld_debug_flags, 0)
  74 #endif
  75
  76
  77 static boolean gallivm_initialized = FALSE;
  78
  79 unsigned lp_native_vector_width;
  80
  81
  82 /*
  83  * Optimization values are:
  84  * - 0: None (-O0)
  85  * - 1: Less (-O1)
  86  * - 2: Default (-O2, -Os)
  87  * - 3: Aggressive (-O3)
  88  *
  89  * See also CodeGenOpt::Level in llvm/Target/TargetMachine.h
  90  */
  91 enum LLVM_CodeGenOpt_Level {
  92    None,        // -O0
  93    Less,        // -O1
  94    Default,     // -O2, -Os
  95    Aggressive   // -O3
  96 };
  97
  98
  99 /**
 100  * Create the LLVM (optimization) pass manager and install
 101  * relevant optimization passes.
 102  * \return  TRUE for success, FALSE for failure
 103  */
 104 static boolean
 105 create_pass_manager(struct gallivm_state *gallivm)
 106 {
 107    assert(!gallivm->passmgr);
 108    assert(gallivm->target);
 109
 110    gallivm->passmgr = LLVMCreateFunctionPassManagerForModule(gallivm->module);
 111    if (!gallivm->passmgr)
 112       return FALSE;
 113    /*
 114     * TODO: some per module pass manager with IPO passes might be helpful -
 115     * the generated texture functions may benefit from inlining if they are
 116     * simple, or constant propagation into them, etc.
 117     */
 118
 119 #if HAVE_LLVM < 0x0309
 120    // Old versions of LLVM get the DataLayout from the pass manager.
 121    LLVMAddTargetData(gallivm->target, gallivm->passmgr);
 122 #endif
 123
 124    /* Setting the module's DataLayout to an empty string will cause the
 125     * ExecutionEngine to copy to the DataLayout string from its target
 126     * machine to the module.  As of LLVM 3.8 the module and the execution
 127     * engine are required to have the same DataLayout.
 128     *
 129     * TODO: This is just a temporary work-around.  The correct solution is
 130     * for gallivm_init_state() to create a TargetMachine and pull the
 131     * DataLayout from there.  Currently, the TargetMachine used by llvmpipe
 132     * is being implicitly created by the EngineBuilder in
 133     * lp_build_create_jit_compiler_for_module()
 134     */
 135
 136 #if HAVE_LLVM < 0x0308
 137    {
 138       char *td_str;
 139       // New ones from the Module.
 140       td_str = LLVMCopyStringRepOfTargetData(gallivm->target);
 141       LLVMSetDataLayout(gallivm->module, td_str);
 142       free(td_str);
 143    }
 144 #else
 145    LLVMSetDataLayout(gallivm->module, "");
 146 #endif
 147
 148    if ((gallivm_debug & GALLIVM_DEBUG_NO_OPT) == 0) {
 149       /* These are the passes currently listed in llvm-c/Transforms/Scalar.h,
 150        * but there are more on SVN.
 151        * TODO: Add more passes.
 152        */
 153       LLVMAddScalarReplAggregatesPass(gallivm->passmgr);
 154       LLVMAddLICMPass(gallivm->passmgr);
 155       LLVMAddCFGSimplificationPass(gallivm->passmgr);
 156       LLVMAddReassociatePass(gallivm->passmgr);
 157       LLVMAddPromoteMemoryToRegisterPass(gallivm->passmgr);
 158       LLVMAddConstantPropagationPass(gallivm->passmgr);
 159       LLVMAddInstructionCombiningPass(gallivm->passmgr);
 160       LLVMAddGVNPass(gallivm->passmgr);
 161    }
 162    else {
 163       /* We need at least this pass to prevent the backends to fail in
 164        * unexpected ways.
 165        */
 166       LLVMAddPromoteMemoryToRegisterPass(gallivm->passmgr);
 167    }
 168
 169    return TRUE;
 170 }
 171
 172
 173 /**
 174  * Free gallivm object's LLVM allocations, but not any generated code
 175  * nor the gallivm object itself.
 176  */
 177 void
 178 gallivm_free_ir(struct gallivm_state *gallivm)
 179 {
 180    if (gallivm->passmgr) {
 181       LLVMDisposePassManager(gallivm->passmgr);
 182    }
 183
 184    if (gallivm->engine) {
 185       /* This will already destroy any associated module */
 186       LLVMDisposeExecutionEngine(gallivm->engine);
 187    } else if (gallivm->module) {
 188       LLVMDisposeModule(gallivm->module);
 189    }
 190
 191    FREE(gallivm->module_name);
 192
 193    if (!USE_MCJIT) {
 194       /* Don't free the TargetData, it's owned by the exec engine */
 195    } else {
 196       if (gallivm->target) {
 197          LLVMDisposeTargetData(gallivm->target);
 198       }
 199    }
 200
 201    if (gallivm->builder)
 202       LLVMDisposeBuilder(gallivm->builder);
 203
 204    /* The LLVMContext should be owned by the parent of gallivm. */
 205
 206    gallivm->engine = NULL;
 207    gallivm->target = NULL;
 208    gallivm->module = NULL;
 209    gallivm->module_name = NULL;
 210    gallivm->passmgr = NULL;
 211    gallivm->context = NULL;
 212    gallivm->builder = NULL;
 213 }
 214
 215
 216 /**
 217  * Free LLVM-generated code.  Should be done AFTER gallivm_free_ir().
 218  */
 219 static void
 220 gallivm_free_code(struct gallivm_state *gallivm)
 221 {
 222    assert(!gallivm->module);
 223    assert(!gallivm->engine);
 224    lp_free_generated_code(gallivm->code);
 225    gallivm->code = NULL;
 226    lp_free_memory_manager(gallivm->memorymgr);
 227    gallivm->memorymgr = NULL;
 228 }
 229
 230
 231 static boolean
 232 init_gallivm_engine(struct gallivm_state *gallivm)
 233 {
 234    if (1) {
 235       enum LLVM_CodeGenOpt_Level optlevel;
 236       char *error = NULL;
 237       int ret;
 238
 239       if (gallivm_debug & GALLIVM_DEBUG_NO_OPT) {
 240          optlevel = None;
 241       }
 242       else {
 243          optlevel = Default;
 244       }
 245
 246       ret = lp_build_create_jit_compiler_for_module(&gallivm->engine,
 247                                                     &gallivm->code,
 248                                                     gallivm->module,
 249                                                     gallivm->memorymgr,
 250                                                     (unsigned) optlevel,
 251                                                     USE_MCJIT,
 252                                                     &error);
 253       if (ret) {
 254          _debug_printf("%s\n", error);
 255          LLVMDisposeMessage(error);
 256          goto fail;
 257       }
 258    }
 259
 260    if (!USE_MCJIT) {
 261       gallivm->target = LLVMGetExecutionEngineTargetData(gallivm->engine);
 262       if (!gallivm->target)
 263          goto fail;
 264    } else {
 265       if (0) {
 266           /*
 267            * Dump the data layout strings.
 268            */
 269
 270           LLVMTargetDataRef target = LLVMGetExecutionEngineTargetData(gallivm->engine);
 271           char *data_layout;
 272           char *engine_data_layout;
 273
 274           data_layout = LLVMCopyStringRepOfTargetData(gallivm->target);
 275           engine_data_layout = LLVMCopyStringRepOfTargetData(target);
 276
 277           if (1) {
 278              debug_printf("module target data = %s\n", data_layout);
 279              debug_printf("engine target data = %s\n", engine_data_layout);
 280           }
 281
 282           free(data_layout);
 283           free(engine_data_layout);
 284       }
 285    }
 286
 287    return TRUE;
 288
 289 fail:
 290    return FALSE;
 291 }
 292
 293
 294 /**
 295  * Allocate gallivm LLVM objects.
 296  * \return  TRUE for success, FALSE for failure
 297  */
 298 static boolean
 299 init_gallivm_state(struct gallivm_state *gallivm, const char *name,
 300                    LLVMContextRef context)
 301 {
 302    assert(!gallivm->context);
 303    assert(!gallivm->module);
 304
 305    if (!lp_build_init())
 306       return FALSE;
 307
 308    gallivm->context = context;
 309
 310    if (!gallivm->context)
 311       goto fail;
 312
 313    gallivm->module_name = NULL;
 314    if (name) {
 315       size_t size = strlen(name) + 1;
 316       gallivm->module_name = MALLOC(size);
 317       if (gallivm->module_name) {
 318          memcpy(gallivm->module_name, name, size);
 319       }
 320    }
 321
 322    gallivm->module = LLVMModuleCreateWithNameInContext(name,
 323                                                        gallivm->context);
 324    if (!gallivm->module)
 325       goto fail;
 326
 327    gallivm->builder = LLVMCreateBuilderInContext(gallivm->context);
 328    if (!gallivm->builder)
 329       goto fail;
 330
 331    gallivm->memorymgr = lp_get_default_memory_manager();
 332    if (!gallivm->memorymgr)
 333       goto fail;
 334
 335    /* FIXME: MC-JIT only allows compiling one module at a time, and it must be
 336     * complete when MC-JIT is created. So defer the MC-JIT engine creation for
 337     * now.
 338     */
 339    if (!USE_MCJIT) {
 340       if (!init_gallivm_engine(gallivm)) {
 341          goto fail;
 342       }
 343    } else {
 344       /*
 345        * MC-JIT engine compiles the module immediately on creation, so we can't
 346        * obtain the target data from it.  Instead we create a target data layout
 347        * from a string.
 348        *
 349        * The produced layout strings are not precisely the same, but should make
 350        * no difference for the kind of optimization passes we run.
 351        *
 352        * For reference this is the layout string on x64:
 353        *
 354        *   e-p:64:64:64-S128-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f16:16:16-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-f128:128:128-n8:16:32:64
 355        *
 356        * See also:
 357        * - http://llvm.org/docs/LangRef.html#datalayout
 358        */
 359
 360       {
 361          const unsigned pointer_size = 8 * sizeof(void *);
 362          char layout[512];
 363          util_snprintf(layout, sizeof layout, "%c-p:%u:%u:%u-i64:64:64-a0:0:%u-s0:%u:%u",
 364 #ifdef PIPE_ARCH_LITTLE_ENDIAN
 365                        'e', // little endian
 366 #else
 367                        'E', // big endian
 368 #endif
 369                        pointer_size, pointer_size, pointer_size, // pointer size, abi alignment, preferred alignment
 370                        pointer_size, // aggregate preferred alignment
 371                        pointer_size, pointer_size); // stack objects abi alignment, preferred alignment
 372
 373          gallivm->target = LLVMCreateTargetData(layout);
 374          if (!gallivm->target) {
 375             return FALSE;
 376          }
 377       }
 378    }
 379
 380    if (!create_pass_manager(gallivm))
 381       goto fail;
 382
 383    return TRUE;
 384
 385 fail:
 386    gallivm_free_ir(gallivm);
 387    gallivm_free_code(gallivm);
 388    return FALSE;
 389 }
 390
 391
 392 boolean
 393 lp_build_init(void)
 394 {
 395    if (gallivm_initialized)
 396       return TRUE;
 397
 398    LLVMLinkInMCJIT();
 399 #if !defined(USE_MCJIT)
 400    USE_MCJIT = debug_get_bool_option("GALLIVM_MCJIT", 0);
 401    LLVMLinkInJIT();
 402 #endif
 403
 404 #ifdef DEBUG
 405    gallivm_debug = debug_get_option_gallivm_debug();
 406 #endif
 407
 408    lp_set_target_options();
 409
 410    util_cpu_detect();
 411
 412    /* For simulating less capable machines */
 413 #ifdef DEBUG
 414    if (debug_get_bool_option("LP_FORCE_SSE2", FALSE)) {
 415       assert(util_cpu_caps.has_sse2);
 416       util_cpu_caps.has_sse3 = 0;
 417       util_cpu_caps.has_ssse3 = 0;
 418       util_cpu_caps.has_sse4_1 = 0;
 419       util_cpu_caps.has_sse4_2 = 0;
 420       util_cpu_caps.has_avx = 0;
 421       util_cpu_caps.has_avx2 = 0;
 422       util_cpu_caps.has_f16c = 0;
 423       util_cpu_caps.has_fma = 0;
 424    }
 425 #endif
 426
 427    /* AMD Bulldozer AVX's throughput is the same as SSE2; and because using
 428     * 8-wide vector needs more floating ops than 4-wide (due to padding), it is
 429     * actually more efficient to use 4-wide vectors on this processor.
 430     *
 431     * See also:
 432     * - http://www.anandtech.com/show/4955/the-bulldozer-review-amd-fx8150-tested/2
 433     */
 434    if (util_cpu_caps.has_avx &&
 435        util_cpu_caps.has_intel) {
 436       lp_native_vector_width = 256;
 437    } else {
 438       /* Leave it at 128, even when no SIMD extensions are available.
 439        * Really needs to be a multiple of 128 so can fit 4 floats.
 440        */
 441       lp_native_vector_width = 128;
 442    }
 443
 444    lp_native_vector_width = debug_get_num_option("LP_NATIVE_VECTOR_WIDTH",
 445                                                  lp_native_vector_width);
 446
 447    if (lp_native_vector_width <= 128) {
 448       /* Hide AVX support, as often LLVM AVX intrinsics are only guarded by
 449        * "util_cpu_caps.has_avx" predicate, and lack the
 450        * "lp_native_vector_width > 128" predicate. And also to ensure a more
 451        * consistent behavior, allowing one to test SSE2 on AVX machines.
 452        * XXX: should not play games with util_cpu_caps directly as it might
 453        * get used for other things outside llvm too.
 454        */
 455       util_cpu_caps.has_avx = 0;
 456       util_cpu_caps.has_avx2 = 0;
 457       util_cpu_caps.has_f16c = 0;
 458       util_cpu_caps.has_fma = 0;
 459    }
 460
 461 #ifdef PIPE_ARCH_PPC_64
 462    /* Set the NJ bit in VSCR to 0 so denormalized values are handled as
 463     * specified by IEEE standard (PowerISA 2.06 - Section 6.3). This guarantees
 464     * that some rounding and half-float to float handling does not round
 465     * incorrectly to 0.
 466     * XXX: should eventually follow same logic on all platforms.
 467     * Right now denorms get explicitly disabled (but elsewhere) for x86,
 468     * whereas ppc64 explicitly enables them...
 469     */
 470    if (util_cpu_caps.has_altivec) {
 471       unsigned short mask[] = { 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
 472                                 0xFFFF, 0xFFFF, 0xFFFE, 0xFFFF };
 473       __asm (
 474         "mfvscr %%v1\n"
 475         "vand   %0,%%v1,%0\n"
 476         "mtvscr %0"
 477         :
 478         : "r" (*mask)
 479       );
 480    }
 481 #endif
 482
 483    gallivm_initialized = TRUE;
 484
 485    return TRUE;
 486 }
 487
 488
 489
 490 /**
 491  * Create a new gallivm_state object.
 492  */
 493 struct gallivm_state *
 494 gallivm_create(const char *name, LLVMContextRef context)
 495 {
 496    struct gallivm_state *gallivm;
 497
 498    gallivm = CALLOC_STRUCT(gallivm_state);
 499    if (gallivm) {
 500       if (!init_gallivm_state(gallivm, name, context)) {
 501          FREE(gallivm);
 502          gallivm = NULL;
 503       }
 504    }
 505
 506    return gallivm;
 507 }
 508
 509
 510 /**
 511  * Destroy a gallivm_state object.
 512  */
 513 void
 514 gallivm_destroy(struct gallivm_state *gallivm)
 515 {
 516    gallivm_free_ir(gallivm);
 517    gallivm_free_code(gallivm);
 518    FREE(gallivm);
 519 }
 520
 521
 522 /**
 523  * Validate a function.
 524  * Verification is only done with debug builds.
 525  */
 526 void
 527 gallivm_verify_function(struct gallivm_state *gallivm,
 528                         LLVMValueRef func)
 529 {
 530    /* Verify the LLVM IR.  If invalid, dump and abort */
 531 #ifdef DEBUG
 532    if (LLVMVerifyFunction(func, LLVMPrintMessageAction)) {
 533       lp_debug_dump_value(func);
 534       assert(0);
 535       return;
 536    }
 537 #endif
 538
 539    if (gallivm_debug & GALLIVM_DEBUG_IR) {
 540       /* Print the LLVM IR to stderr */
 541       lp_debug_dump_value(func);
 542       debug_printf("\n");
 543    }
 544 }
 545
 546
 547 /**
 548  * Compile a module.
 549  * This does IR optimization on all functions in the module.
 550  */
 551 void
 552 gallivm_compile_module(struct gallivm_state *gallivm)
 553 {
 554    LLVMValueRef func;
 555    int64_t time_begin = 0;
 556
 557    assert(!gallivm->compiled);
 558
 559    if (gallivm->builder) {
 560       LLVMDisposeBuilder(gallivm->builder);
 561       gallivm->builder = NULL;
 562    }
 563
 564    if (gallivm_debug & GALLIVM_DEBUG_PERF)
 565       time_begin = os_time_get();
 566
 567    /* Run optimization passes */
 568    LLVMInitializeFunctionPassManager(gallivm->passmgr);
 569    func = LLVMGetFirstFunction(gallivm->module);
 570    while (func) {
 571       if (0) {
 572          debug_printf("optimizing func %s...\n", LLVMGetValueName(func));
 573       }
 574
 575    /* Disable frame pointer omission on debug/profile builds */
 576    /* XXX: And workaround http://llvm.org/PR21435 */
 577 #if HAVE_LLVM >= 0x0307 && \
 578     (defined(DEBUG) || defined(PROFILE) || \
 579      defined(PIPE_ARCH_X86) || defined(PIPE_ARCH_X86_64))
 580       LLVMAddTargetDependentFunctionAttr(func, "no-frame-pointer-elim", "true");
 581       LLVMAddTargetDependentFunctionAttr(func, "no-frame-pointer-elim-non-leaf", "true");
 582 #endif
 583
 584       LLVMRunFunctionPassManager(gallivm->passmgr, func);
 585       func = LLVMGetNextFunction(func);
 586    }
 587    LLVMFinalizeFunctionPassManager(gallivm->passmgr);
 588
 589    if (gallivm_debug & GALLIVM_DEBUG_PERF) {
 590       int64_t time_end = os_time_get();
 591       int time_msec = (int)(time_end - time_begin) / 1000;
 592       assert(gallivm->module_name);
 593       debug_printf("optimizing module %s took %d msec\n",
 594                    gallivm->module_name, time_msec);
 595    }
 596
 597    /* Dump byte code to a file */
 598    if (gallivm_debug & GALLIVM_DEBUG_DUMP_BC) {
 599       char filename[256];
 600       assert(gallivm->module_name);
 601       util_snprintf(filename, sizeof(filename), "ir_%s.bc", gallivm->module_name);
 602       LLVMWriteBitcodeToFile(gallivm->module, filename);
 603       debug_printf("%s written\n", filename);
 604       debug_printf("Invoke as \"llc -o - %s\"\n", filename);
 605    }
 606
 607    if (USE_MCJIT) {
 608       assert(!gallivm->engine);
 609       if (!init_gallivm_engine(gallivm)) {
 610          assert(0);
 611       }
 612    }
 613    assert(gallivm->engine);
 614
 615    ++gallivm->compiled;
 616
 617    if (gallivm_debug & GALLIVM_DEBUG_ASM) {
 618       LLVMValueRef llvm_func = LLVMGetFirstFunction(gallivm->module);
 619
 620       while (llvm_func) {
 621          /*
 622           * Need to filter out functions which don't have an implementation,
 623           * such as the intrinsics. May not be sufficient in case of IPO?
 624           * LLVMGetPointerToGlobal() will abort otherwise.
 625           */
 626          if (!LLVMIsDeclaration(llvm_func)) {
 627             void *func_code = LLVMGetPointerToGlobal(gallivm->engine, llvm_func);
 628             lp_disassemble(llvm_func, func_code);
 629          }
 630          llvm_func = LLVMGetNextFunction(llvm_func);
 631       }
 632    }
 633
 634 #if defined(PROFILE)
 635    {
 636       LLVMValueRef llvm_func = LLVMGetFirstFunction(gallivm->module);
 637
 638       while (llvm_func) {
 639          if (!LLVMIsDeclaration(llvm_func)) {
 640             void *func_code = LLVMGetPointerToGlobal(gallivm->engine, llvm_func);
 641             lp_profile(llvm_func, func_code);
 642          }
 643          llvm_func = LLVMGetNextFunction(llvm_func);
 644       }
 645    }
 646 #endif
 647 }
 648
 649
 650
 651 func_pointer
 652 gallivm_jit_function(struct gallivm_state *gallivm,
 653                      LLVMValueRef func)
 654 {
 655    void *code;
 656    func_pointer jit_func;
 657
 658    assert(gallivm->compiled);
 659    assert(gallivm->engine);
 660
 661    code = LLVMGetPointerToGlobal(gallivm->engine, func);
 662    assert(code);
 663    jit_func = pointer_to_func(code);
 664
 665    return jit_func;
 666 }