sepcomp: add option `--guard-call`

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/compiler/separate_compiler.nit b/src/compiler/separate_compiler.nit
index 9273c45..55ad13a 100644 (file)
--- a/src/compiler/separate_compiler.nit
+++ b/src/compiler/separate_compiler.nit
@@ -34,6 +34,8 @@ redef class ToolContext
        var opt_colors_are_symbols = new OptionBool("Store colors as symbols (link-boost)", "--colors-are-symbols")
        # --trampoline-call
        var opt_trampoline_call = new OptionBool("Use an indirection when calling", "--trampoline-call")
+       # --guard-call
+       var opt_guard_call = new OptionBool("Guard VFT calls with a direct call", "--guard-call")
        # --substitute-monomorph
        var opt_substitute_monomorph = new OptionBool("Replace monomorph trampoline with direct call (link-boost)", "--substitute-monomorph")
        # --link-boost
@@ -61,7 +63,7 @@ redef class ToolContext
                self.option_context.add_option(self.opt_no_inline_intern)
                self.option_context.add_option(self.opt_no_union_attribute)
                self.option_context.add_option(self.opt_no_shortcut_equate)
-               self.option_context.add_option(opt_colors_are_symbols, opt_trampoline_call, opt_substitute_monomorph, opt_link_boost)
+               self.option_context.add_option(opt_colors_are_symbols, opt_trampoline_call, opt_guard_call, opt_substitute_monomorph, opt_link_boost)
                self.option_context.add_option(self.opt_inline_coloring_numbers, opt_inline_some_methods, opt_direct_call_monomorph, opt_skip_dead_methods, opt_semi_global)
                self.option_context.add_option(self.opt_colo_dead_methods)
                self.option_context.add_option(self.opt_tables_metrics)
@@ -590,7 +592,7 @@ class SeparateCompiler
        # Process all introduced methods and compile some linking information (if needed)
        fun link_mmethods
        do
-               if not modelbuilder.toolcontext.opt_substitute_monomorph.value then return
+               if not modelbuilder.toolcontext.opt_substitute_monomorph.value and not modelbuilder.toolcontext.opt_guard_call.value then return
 
                for mmodule in mainmodule.in_importation.greaters do
                        for cd in mmodule.mclassdefs do
@@ -613,6 +615,11 @@ class SeparateCompiler
                        linker_script.add("{n2} = {md.virtual_runtime_function.c_name};")
                end
 
+               # If opt_substitute_monomorph then a trampoline is used, else a weak symbol is used
+               if modelbuilder.toolcontext.opt_guard_call.value then
+                       var r = m.intro.virtual_runtime_function
+                       provide_declaration(n2, "{r.c_ret} {n2}{r.c_sig} __attribute__((weak));")
+               end
        end
 
        # The single mmethodef called in case of monomorphism.
@@ -1279,20 +1286,28 @@ class SeparateCompilerVisitor
                end
 
                var const_color = mentity.const_color
-               var call
-               if not compiler.modelbuilder.toolcontext.opt_trampoline_call.value then
-                       self.require_declaration(const_color)
-                       call = "(({runtime_function.c_funptrtype})({arguments.first}->class->vft[{const_color}]))({ss}) /* {mmethod} on {arguments.first.inspect}*/"
+               var ress
+               if res != null then
+                       ress = "{res} = "
                else
+                       ress = ""
+               end
+               if mentity isa MMethod and compiler.modelbuilder.toolcontext.opt_guard_call.value then
                        var callsym = "CALL_" + const_color
                        self.require_declaration(callsym)
-                       call = "{callsym}({ss}) /* {mmethod} on {arguments.first.inspect}*/"
-               end
-
-               if res != null then
-                       self.add("{res} = {call};")
+                       self.add "if (!{callsym}) \{"
+                       self.require_declaration(const_color)
+                       self.add "{ress}(({runtime_function.c_funptrtype})({arguments.first}->class->vft[{const_color}]))({ss}); /* {mmethod} on {arguments.first.inspect}*/"
+                       self.add "\} else \{"
+                       self.add "{ress}{callsym}({ss}); /* {mmethod} on {arguments.first.inspect}*/"
+                       self.add "\}"
+               else if mentity isa MMethod and compiler.modelbuilder.toolcontext.opt_trampoline_call.value then
+                       var callsym = "CALL_" + const_color
+                       self.require_declaration(callsym)
+                       self.add "{ress}{callsym}({ss}); /* {mmethod} on {arguments.first.inspect}*/"
                else
-                       self.add("{call};")
+                       self.require_declaration(const_color)
+                       self.add "{ress}(({runtime_function.c_funptrtype})({arguments.first}->class->vft[{const_color}]))({ss}); /* {mmethod} on {arguments.first.inspect}*/"
                end
 
                if res0 != null then