Add test that ensures opcodes don't overlap unless explicitly specified

2 files changed, 59 insertions, 1 deletions

diff --git a/riscv/check-opcode-overlap.t.cc b/riscv/check-opcode-overlap.t.cc
new file mode 100644
index 0000000..2922001
--- /dev/null
+++ b/riscv/check-opcode-overlap.t.cc
@@ -0,0 +1,57 @@
+#include "decode.h"
+#include "common.h"
+#include <unordered_set>
+#include <vector>
+#include <string>
+#include <cstdio>
+
+struct opcode {
+  insn_bits_t match;
+  insn_bits_t mask;
+  std::string name;
+};
+
+static void check_overlap(const opcode& a, const opcode& b)
+{
+  if ((a.match & b.mask) == b.match) {
+    fprintf(stderr, "Instruction %s (%" PRIx64 ") overlaps instruction %s (%" PRIx64 ", mask %" PRIx64 ")\n",
+            a.name.c_str(), a.match, b.name.c_str(), b.match, b.mask);
+    exit(-1);
+  }
+}
+
+int main()
+{
+  #define DECLARE_INSN(name, match, mask) \
+    const insn_bits_t UNUSED name##_match = (match), name##_mask = (mask);
+    #include "encoding.h"
+  #undef DECLARE_INSN
+
+  static const opcode static_list[] = {
+    #define DEFINE_INSN(name) \
+      {name##_match, name##_mask, #name},
+      #include "insn_list.h"
+    #undef DEFINE_INSN
+  };
+
+  std::unordered_set<std::string> overlap_list;
+  #define DECLARE_OVERLAP_INSN(name, ext) \
+    overlap_list.insert(std::string(#name));
+    #include "overlap_list.h"
+  #undef DECLARE_OVERLAP_INSN
+
+  std::vector<const opcode*> list;
+  for (size_t i = 0; i < sizeof(static_list) / sizeof(static_list[0]); i++) {
+    if (!overlap_list.count(static_list[i].name))
+      list.push_back(&static_list[i]);
+  }
+
+  for (size_t i = 1; i < list.size(); i++) {
+    for (size_t j = 0; j < i; j++) {
+      check_overlap(*list[i], *list[j]);
+      check_overlap(*list[j], *list[i]);
+    }
+  }
+
+  return 0;
+}
diff --git a/riscv/riscv.mk.in b/riscv/riscv.mk.in
index 1cfe627..ac45b28 100644
--- a/riscv/riscv.mk.in
+++ b/riscv/riscv.mk.in
@@ -75,7 +75,8 @@ riscv_srcs = \
 	cfg.cc \
 	$(riscv_gen_srcs) \
 
-riscv_test_srcs =
+riscv_test_srcs = \
+  check-opcode-overlap.t.cc \
 
 riscv_gen_hdrs = \
 	insn_list.h \