setup staq compiler to insert default gate impls not found in staq

Signed-off-by: Alex McCaskey <mccaskeyaj@ornl.gov>

quantum/plugins/staq/compiler/staq_compiler.cpp

@@ -33,6 +33,89 @@ using namespace staq::ast;
 
 namespace xacc {
 
+static std::vector<std::string> builtins{
+    "u3", "u2",   "u1",  "cx",  "id",  "u0",  "x",   "y",  "z",
+    "h",  "s",    "sdg", "t",   "tdg", "rx",  "ry",  "rz", "cz",
+    "cy", "swap", "ch",  "ccx", "crz", "cu1", "cu2", "cu3"};
+
+static std::map<std::string, std::string> missing_builtins{
+    {"u", R"#(
+gate u(theta,phi,lambda) q { U(theta,phi,lambda) q; })#"},
+    {"p", R"#(gate p(theta) a
+{
+  rz(theta) a;
+})#"},
+    {"sx", R"#(gate sx a { sdg a; h a; sdg a; })#"},
+    {"sxdg", R"#(gate sxdg a { s a; h a; s a; })#"},
+    {"cswap", R"#(gate cswap a,b,c
+{
+  cx c,b;
+  ccx a,b,c;
+  cx c,b;
+})#"},
+    {"crx", R"#(gate crx(lambda) a,b
+{
+  u1(pi/2) b;
+  cx a,b;
+  u3(-lambda/2,0,0) b;
+  cx a,b;
+  u3(lambda/2,-pi/2,0) b;
+})#"},
+    {"cry", R"#(gate cry(lambda) a,b
+{
+  u3(lambda/2,0,0) b;
+  cx a,b;
+  u3(-lambda/2,0,0) b;
+  cx a,b;
+  ry(lambda) a;
+})#"},
+    {"cp", R"#(gate cp(lambda) a,b
+{
+  p(lambda/2) a;
+  cx a,b;
+  p(-lambda/2) b;
+  cx a,b;
+  p(lambda/2) b;
+})#"},
+    {"csx", R"#(gate csx a,b { h b; cu1(pi/2) a,b; h b; })#"},
+    {"cu", R"#(gate cu(theta,phi,lambda,gamma) c, t
+{ p(gamma) c;
+  p((lambda+phi)/2) c;
+  p((lambda-phi)/2) t;
+  cx c,t;
+  u(-theta/2,0,-(phi+lambda)/2) t;
+  cx c,t;
+  u(theta/2,phi,0) t;
+})#"},
+    {"rxx", R"#(gate rxx(theta) a,b
+{
+  u3(pi/2, theta, 0) a;
+  h b;
+  cx a,b;
+  u1(-theta) b;
+  cx a,b;
+  h b;
+  u2(-pi, pi-theta) a;
+})#"},
+    {"rzz", R"#(gate rzz(theta) a,b
+{
+  cx a,b;
+  u1(theta) b;
+  cx a,b;
+})#"},
+    {"rccx", R"#(gate rccx a,b,c
+{
+  u2(0,pi) c;
+  u1(pi/4) c;
+  cx b, c;
+  u1(-pi/4) c;
+  cx a, c;
+  u1(pi/4) c;
+  cx b, c;
+  u1(-pi/4) c;
+  u2(0,pi) c;
+})#"}};
+
 StaqCompiler::StaqCompiler() {}
 
 bool StaqCompiler::canParse(const std::string &src) {
@@ -190,10 +273,43 @@ std::shared_ptr<IR> StaqCompiler::compile(const std::string &src,
     _src = "OPENQASM 2.0;\n" + _src;
   }
 
+
+  std::string preamble = "include \"qelib1.inc\";";
+  auto preamble_start = src.find(preamble);
+
+ // Add any required missing pre-defines that we 
+  // know the impl for.
+  std::vector<std::string> added;
+  std::string extra_insts = "\n";
+  bool hasMeasures = false;
+  auto tmp_lines = split(_src, '\n');
+  for (auto line : tmp_lines) {
+    if (line.find("OPENQASM") == std::string::npos &&
+        line.find("include") == std::string::npos &&
+        line.find("measure") == std::string::npos &&
+        line.find("qreg") == std::string::npos &&
+        line.find("creg") == std::string::npos) {
+      auto inst_name = split(line, ' ')[0];
+      if (inst_name.find("(") != std::string::npos) {
+        inst_name = inst_name.substr(0, inst_name.find("("));
+      }
+      if (std::find(builtins.begin(), builtins.end(), inst_name) ==
+              builtins.end() &&
+          std::find(added.begin(), added.end(), inst_name) == added.end()) {
+        extra_insts += missing_builtins[inst_name] + "\n";
+        added.push_back(inst_name);
+      }
+    }
+  }
+  _src.insert(preamble_start+preamble.length(), extra_insts);
+
+
   using namespace staq;
   ast::ptr<ast::Program> prog;
   try {
     prog = parser::parse_string(_src);
+        // transformations::inline_ast(*prog);
+
     transformations::desugar(*prog);
     transformations::synthesize_oracles(*prog);
   } catch (std::exception &e) {