triggers: legalize timing=1(after) for load data trigger

As recommended in the debug spec table "Suggested Trigger Timings", to
avoid the footgun of replaying a load (which may have side effects) when
the breakpoint trap handler returns.

reference: https://github.com/riscv-software-src/riscv-isa-sim/pull/1208#issuecomment-1373035906

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The legalize_timing() depends on select, execution, load, and store,
which are updated in the same function tdata1_write(). As a result,
reordering statements in the tdata1_write() may break the functionality.

Passing those variables as parameters to legalize_timing() does not
solve the problem. Thus, we give the original write value and the masks
of the variables to the legalize_timing(). This makes the legalization
function independent of the updating variables and resolves the issue.

reference: https://github.com/riscv-software-src/riscv-isa-sim/pull/1214

1 files changed, 1 insertions, 1 deletions

diff --git a/riscv/triggers.h b/riscv/triggers.h
index 6de0f2d..3fc2275 100644
--- a/riscv/triggers.h
+++ b/riscv/triggers.h
@@ -208,7 +208,7 @@ private:
 
 protected:
   match_t legalize_match(reg_t val) const noexcept;
-  static bool legalize_timing(reg_t val, reg_t timing_mask, reg_t execute_mask) noexcept;
+  static bool legalize_timing(reg_t val, reg_t timing_mask, reg_t select_mask, reg_t execute_mask, reg_t load_mask) noexcept;
   bool dmode = false;
   action_t action = ACTION_DEBUG_EXCEPTION;
   bool hit = false;