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systemc: Get sc_main to work even when dynamically linked.

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Unfortunately multiply defined weak symbols don't work like they're
supposed to when the different versions are across dynamic linking
boundaries.

Fortunately, a weak symbol with no definition at all will still
consistently evaluate as 0, and a singularly defined weak symbol will
still resolve correctly.

Instead of relying on a weak version of sc_main being overridden by a
strong/non-default definition, this change leaves it as undefined and
detects at run time whether the symbol resolves to 0 or to an actual
code location.

Change-Id: I31c4ff769b0c52277c6cf4845ca3f85000009583
Reviewed-on: https://gem5-review.googlesource.com/11610
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
This commit is contained in:
Gabe Black
2018-06-22 14:15:28 -07:00
parent 642fa515b8
commit 97018a3b20
1 changed files with 8 additions and 11 deletions
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19
src/systemc/core/sc_main.cc
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@@ -38,16 +38,8 @@
#include "systemc/ext/core/sc_main.hh"
#include "systemc/ext/utils/sc_report_handler.hh"
// A default version of this function in case one isn't otherwise defined.
// This ensures everything will link properly whether or not the user defined
// a custom sc_main function. If they didn't but still try to call it, throw
// an error and die.
[[gnu::weak]] int
sc_main(int argc, char *argv[])
{
// If python attempts to call sc_main but no sc_main was defined...
fatal("sc_main called but not defined.\n");
}
// A weak symbol to detect if sc_main has been defined, and if so where it is.
[[gnu::weak]] int sc_main(int argc, char *argv[]);
namespace sc_core
{
@@ -65,7 +57,12 @@ class ScMainFiber : public Fiber
void
main()
{
::sc_main(_argc, _argv);
if (::sc_main) {
::sc_main(_argc, _argv);
} else {
// If python tries to call sc_main but no sc_main was defined...
fatal("sc_main called but not defined.\n");
}
}
};