[GR-44350] Define RB_GC_GUARD in a way it cannot be an assignment LHS

PullRequest: truffleruby/3660

Author: eregon

CHANGELOG.md

@@ -242,6 +242,7 @@ Bug fixes:
 * Fix `rb_id2name` to ensure the native string will have the same lifetime as the id (#2630, @aardvark179).
 * Fix `Integer#fdiv` and `Rational#to_f` for large `Integer` values (#2631, @bjfish).
 * Remove the `RB_NEWOBJ/NEWOBJ` and `OBJSETUP` macros since we cannot support them in TruffleRuby and native extensions may use `#ifdef` to detect features (#2869, @nirvdrum).
+* Fix memory leak in `--native` mode for native extension handles and native pointers (@eregon).
 
 Compatibility:
 

lib/cext/ABI_version.txt

@@ -1 +1 @@
-2
+3

lib/cext/include/ruby/internal/memory.h

@@ -158,12 +158,10 @@ typedef uint128_t DSIZE_T;
  * @post   `v` is still alive.
  */
 #ifdef TRUFFLERUBY
-#define RB_GC_GUARD(v) \
-    (*__extension__ ({ \
-       polyglot_invoke(RUBY_CEXT, "rb_tr_gc_guard", v); \
-       volatile VALUE *rb_gc_guarded_ptr = &v; \
-       rb_gc_guarded_ptr; \
-    }))
+RBIMPL_SYMBOL_EXPORT_BEGIN()
+VALUE rb_tr_gc_guard(VALUE value);
+RBIMPL_SYMBOL_EXPORT_END()
+#define RB_GC_GUARD(v) rb_tr_gc_guard(v)
 #else
 #ifdef __GNUC__
 #define RB_GC_GUARD(v) \

src/main/c/bigdecimal/bigdecimal.c

@@ -3953,11 +3953,14 @@ BigMath_s_log(VALUE klass, VALUE x, VALUE vprec)
     }
     x = VpCheckGetValue(vx);
 
-    RB_GC_GUARD(one) = VpCheckGetValue(VpCreateRbObject(1, "1", true));
-    RB_GC_GUARD(two) = VpCheckGetValue(VpCreateRbObject(1, "2", true));
+    one = VpCheckGetValue(VpCreateRbObject(1, "1", true));
+    two = VpCheckGetValue(VpCreateRbObject(1, "2", true));
+    RB_GC_GUARD(one);
+    RB_GC_GUARD(two);
 
     n = prec + BIGDECIMAL_DOUBLE_FIGURES;
-    RB_GC_GUARD(vn) = SSIZET2NUM(n);
+    vn = SSIZET2NUM(n);
+    RB_GC_GUARD(vn);
     expo = VpExponent10(vx);
     if (expo < 0 || expo >= 3) {
 	char buf[DECIMAL_SIZE_OF_BITS(SIZEOF_VALUE * CHAR_BIT) + 4];
@@ -3969,9 +3972,12 @@ BigMath_s_log(VALUE klass, VALUE x, VALUE vprec)
     }
     w = BigDecimal_sub(x, one);
     x = BigDecimal_div2(w, BigDecimal_add(x, one), vn);
-    RB_GC_GUARD(x2) = BigDecimal_mult2(x, x, vn);
-    RB_GC_GUARD(y)  = x;
-    RB_GC_GUARD(d)  = y;
+    x2 = BigDecimal_mult2(x, x, vn);
+    y = x;
+    d = y;
+    RB_GC_GUARD(x2);
+    RB_GC_GUARD(y);
+    RB_GC_GUARD(d);
     i = 1;
     while (!VpIsZero((Real*)DATA_PTR(d))) {
 	SIGNED_VALUE const ey = VpExponent10(DATA_PTR(y));

src/main/c/cext/gc.c

@@ -12,6 +12,11 @@
 
 // GC, rb_gc_*
 
+VALUE rb_tr_gc_guard(VALUE value) {
+  polyglot_invoke(RUBY_CEXT, "rb_tr_gc_guard", value);
+  return value;
+}
+
 void rb_global_variable(VALUE *address) {
   rb_gc_register_address(address);
 }

test/mri/tests/lib/core_assertions.rb

@@ -31,7 +31,7 @@ def message msg = nil, ending = nil, &default
     end
 
     module CoreAssertions
-      ALLOW_SUBPROCESSES = true # !defined?(::TruffleRuby)
+      ALLOW_SUBPROCESSES = ENV['MRI_TEST_SUBPROCESSES'] != 'false' # !defined?(::TruffleRuby)
 
       require_relative 'envutil'
       require 'pp'

tool/jt.rb

@@ -823,6 +823,7 @@ def help
       jt test mri test/mri/tests/test_find.rb [-- <MRI runner options>]
                                                      run tests in given file, -n option of the runner can be used to further
                                                      limit executed test methods
+        MRI_TEST_SUBPROCESSES=false                  skip MRI tests using subprocesses
       jt retag FILE                                  Remove MRI excludes and re-add as necessary for MRI tests
       ---
       jt test basictest                              run MRI's basictest suite