Add a codegen option to disable use of jlplts (#51123)

Alternative to #51108 with the
same objectives.

Author: Keno

base/reflection.jl

@@ -1219,6 +1219,7 @@ struct CodegenParams
     debug_info_kind::Cint
     safepoint_on_entry::Cint
     gcstack_arg::Cint
+    use_jlplt::Cint
 
     lookup::Ptr{Cvoid}
 
@@ -1228,15 +1229,15 @@ struct CodegenParams
                    prefer_specsig::Bool=false,
                    gnu_pubnames=true, debug_info_kind::Cint = default_debug_info_kind(),
                    safepoint_on_entry::Bool=true,
-                   gcstack_arg::Bool=true,
+                   gcstack_arg::Bool=true, use_jlplt::Bool=true,
                    lookup::Ptr{Cvoid}=unsafe_load(cglobal(:jl_rettype_inferred_addr, Ptr{Cvoid})),
                    generic_context = nothing)
         return new(
             Cint(track_allocations), Cint(code_coverage),
             Cint(prefer_specsig),
             Cint(gnu_pubnames), debug_info_kind,
             Cint(safepoint_on_entry),
-            Cint(gcstack_arg),
+            Cint(gcstack_arg), Cint(use_jlplt),
             lookup, generic_context)
     end
 end

src/ccall.cpp

@@ -2077,6 +2077,14 @@ jl_cgval_t function_sig_t::emit_a_ccall(
         if (ctx.emission_context.imaging_mode)
             jl_printf(JL_STDERR,"WARNING: literal address used in ccall for %s; code cannot be statically compiled\n", symarg.f_name);
     }
+    else if (!ctx.params->use_jlplt) {
+        if ((symarg.f_lib && !((symarg.f_lib == JL_EXE_LIBNAME) ||
+              (symarg.f_lib == JL_LIBJULIA_INTERNAL_DL_LIBNAME) ||
+              (symarg.f_lib == JL_LIBJULIA_DL_LIBNAME))) || symarg.lib_expr) {
+            emit_error(ctx, "ccall: Had library expression, but symbol lookup was disabled");
+        }
+        llvmf = jl_Module->getOrInsertFunction(symarg.f_name, functype).getCallee();
+    }
     else {
         assert(symarg.f_name != NULL);
         PointerType *funcptype = PointerType::get(functype, 0);

src/codegen.cpp

@@ -1351,17 +1351,23 @@ static const auto jl_new_opaque_closure_jlcall_func = new JuliaFunction<>{XSTR(j
 static _Atomic(uint64_t) globalUniqueGeneratedNames{1};
 
 // --- code generation ---
+
 extern "C" {
-    jl_cgparams_t jl_default_cgparams = {1, 1, 0,
+    jl_cgparams_t jl_default_cgparams = {
+        /* track_allocations */ 1,
+        /* code_coverage */ 1,
+        /* prefer_specsig */ 0,
 #ifdef _OS_WINDOWS_
-        0,
+        /* gnu_pubnames */ 0,
 #else
-        1,
+        /* gnu_pubnames */ 1,
 #endif
-        (int) DICompileUnit::DebugEmissionKind::FullDebug,
-        1,
-        1,
-        jl_rettype_inferred_addr, NULL };
+        /* debug_info_kind */ (int) DICompileUnit::DebugEmissionKind::FullDebug,
+        /* safepoint_on_entry */ 1,
+        /* gcstack_arg */ 1,
+        /* use_jlplt*/ 1,
+        /* lookup */ jl_rettype_inferred_addr,
+        /* generic_context */ NULL };
 }
 
 

src/julia.h

@@ -2367,6 +2367,8 @@ typedef struct {
     int safepoint_on_entry; // Emit a safepoint on entry to each function
     int gcstack_arg; // Pass the ptls value as an argument with swiftself
 
+    int use_jlplt; // Whether to use the Julia PLT mechanism or emit symbols directly
+
     // Cache access. Default: jl_rettype_inferred.
     jl_codeinstance_lookup_t lookup;