accelerate symbol lookup in OrcJIT

CompileLayer.findSymbol is O(n) in the number of modules that have been emitted
but we can pre-compute the result of findSymbolIn when notified that an object has been emitted and store it in one hash table for the JIT

fix #15619

Author: vtjnash

src/codegen.cpp

@@ -1393,9 +1393,7 @@ const jl_value_t *jl_dump_function_asm(void *f, int raw_mc)
 #endif
     const object::ObjectFile *object = NULL;
     assert(fptr != 0);
-    bool isJIT = true;
     if (!jl_DI_for_fptr(fptr, &symsize, &slide, &section_slide, &object, &context)) {
-        isJIT = false;
         if (!jl_dylib_DI_for_fptr(fptr, &object, &objcontext, &slide, &section_slide, false,
             NULL, NULL, NULL, NULL)) {
                 jl_printf(JL_STDERR, "WARNING: Unable to find function pointer\n");
@@ -1410,9 +1408,6 @@ const jl_value_t *jl_dump_function_asm(void *f, int raw_mc)
     }
 
     if (raw_mc) {
-#ifdef LLVM37
-        jl_cleanup_DI(context);
-#endif
         return (jl_value_t*)jl_pchar_to_array((char*)fptr, symsize);
     }
 
@@ -1428,10 +1423,7 @@ const jl_value_t *jl_dump_function_asm(void *f, int raw_mc)
 #endif
             );
 
-#ifdef LLVM37
-    if (isJIT)
-        jl_cleanup_DI(context);
-#else
+#ifndef LLVM37
     fstream.flush();
 #endif
 

src/codegen_internal.h

@@ -27,10 +27,6 @@ extern int jl_DI_for_fptr(uint64_t fptr, uint64_t *symsize, int64_t *slide, int6
 extern bool jl_dylib_DI_for_fptr(size_t pointer, const object::ObjectFile **object, llvm::DIContext **context, int64_t *slide, int64_t *section_slide,
         bool onlySysImg, bool *isSysImg, void **saddr, char **name, char **filename);
 
-#ifdef USE_MCJIT
-extern void jl_cleanup_DI(llvm::DIContext *context);
-#endif
-
 #ifdef USE_ORCJIT
 extern JL_DLLEXPORT void ORCNotifyObjectEmitted(JITEventListener *Listener,
                                       const object::ObjectFile &obj,

src/debuginfo.cpp

@@ -91,10 +91,8 @@ struct ObjectInfo {
     const object::ObjectFile *object;
     size_t SectionSize;
     ptrdiff_t slide;
-#ifdef LLVM39
+#ifdef LLVM37
     DIContext *context;
-#elif defined(LLVM37)
-    const llvm::LoadedObjectInfo *L;
 #endif
 #if defined(_OS_DARWIN_) && !defined(LLVM37)
     const char *name;
@@ -444,11 +442,7 @@ class JuliaJITEventListener: public JITEventListener
                 ObjectInfo tmp = {&debugObj,
                     (size_t)SectionSize,
                     (ptrdiff_t)(SectionAddr - SectionLoadAddr),
-#ifdef LLVM39
                     new DWARFContextInMemory(debugObj, &L),
-#else
-                    L.clone().release(),
-#endif
                     };
                 objectmap[SectionLoadAddr] = tmp;
                 first = false;
@@ -524,11 +518,6 @@ class JuliaJITEventListener: public JITEventListener
 #endif
             ObjectInfo tmp = {objfile, (size_t)Size,
                 (ptrdiff_t)(SectionAddr - SectionLoadAddr),
-#ifdef LLVM39
-                new DWARFContextInMemory(*objfile, &L),
-#elif defined(LLVM37)
-                L.clone().release(),
-#endif
 #ifdef _OS_DARWIN_
                 strndup(sName.data(), sName.size()),
 #endif
@@ -1066,10 +1055,8 @@ int jl_DI_for_fptr(uint64_t fptr, uint64_t *symsize, int64_t *slide, int64_t *se
             *section_slide = fit->second.slide;
         *object = fit->second.object;
         if (context) {
-#if defined(LLVM39)
+#if defined(LLVM37)
             *context = fit->second.context;
-#elif defined(LLVM37)
-            *context = new DWARFContextInMemory(*fit->second.object, fit->second.L);
 #else
             *context = DIContext::getDWARFContext(*fit->second.object);
 #endif
@@ -1121,13 +1108,6 @@ JL_DLLEXPORT uint64_t jl_get_section_start(uint64_t fptr)
 
 #endif
 
-void jl_cleanup_DI(llvm::DIContext *context)
-{
-#ifndef LLVM39
-    delete context;
-#endif
-}
-
 // Set *name and *filename to either NULL or malloc'd string
 void jl_getFunctionInfo(char **name, char **filename, size_t *line,
                         char **inlinedat_file, size_t *inlinedat_line, jl_lambda_info_t **outer_linfo,
@@ -1151,7 +1131,6 @@ void jl_getFunctionInfo(char **name, char **filename, size_t *line,
     if (jl_DI_for_fptr(pointer, &symsize, &slide, NULL, &object, &context)) {
         *outer_linfo = jl_jit_events->lookupLinfo(pointer);
         lookup_pointer(context, name, line, filename, inlinedat_line, inlinedat_file, pointer+slide, 1, fromC);
-        jl_cleanup_DI(context);
         return;
     }
 #else // !USE_MCJIT