emit asmConsts as metadata

Author: kripken

lib/Target/JSBackend/CallHandlers.h

@@ -501,6 +501,30 @@ DEF_CALL_HANDLER(emscripten_float32x4_storexy, {
   return "SIMD_float32x4_storeXY(HEAPU8, " + getValueAsStr(CI->getOperand(0)) + ", " + getValueAsStr(CI->getOperand(1)) + ")";
 })
 
+// EM_ASM support
+
+std::string handleAsmConst(const Instruction *CI, std::string suffix="") {
+  std::string ret = "_emscripten_asm_const" + suffix + "(" + utostr(getAsmConstId(CI->getOperand(0)));
+  unsigned Num = getNumArgOperands(CI);
+  for (unsigned i = 1; i < Num; i++) {
+    ret += ", " + getValueAsCastParenStr(CI->getOperand(i), ASM_NONSPECIFIC);
+  }
+  return ret + ")";
+}
+
+DEF_CALL_HANDLER(emscripten_asm_const, {
+  Declares.insert("emscripten_asm_const");
+  return handleAsmConst(CI);
+})
+DEF_CALL_HANDLER(emscripten_asm_const_int, {
+  Declares.insert("emscripten_asm_const_int");
+  return getAssign(CI) + getCast(handleAsmConst(CI, "_int"), Type::getInt32Ty(CI->getContext()));
+})
+DEF_CALL_HANDLER(emscripten_asm_const_double, {
+  Declares.insert("emscripten_asm_const_double");
+  return getAssign(CI) + getCast(handleAsmConst(CI, "_double"), Type::getDoubleTy(CI->getContext()));
+})
+
 #define DEF_BUILTIN_HANDLER(name, to) \
 DEF_CALL_HANDLER(name, { \
   return CH___default__(CI, #to); \
@@ -674,6 +698,9 @@ void setupCallHandlers() {
   SETUP_CALL_HANDLER(emscripten_float32x4_loadxy);
   SETUP_CALL_HANDLER(emscripten_float32x4_storex);
   SETUP_CALL_HANDLER(emscripten_float32x4_storexy);
+  SETUP_CALL_HANDLER(emscripten_asm_const);
+  SETUP_CALL_HANDLER(emscripten_asm_const_int);
+  SETUP_CALL_HANDLER(emscripten_asm_const_double);
 
   SETUP_CALL_HANDLER(abs);
   SETUP_CALL_HANDLER(labs);

lib/Target/JSBackend/JSBackend.cpp

@@ -150,6 +150,7 @@ namespace {
     std::vector<std::string> GlobalInitializers;
     std::vector<std::string> Exports; // additional exports
     BlockAddressMap BlockAddresses;
+    NameIntMap AsmConsts;
 
     std::string CantValidate;
     bool UsesSIMD;
@@ -365,6 +366,19 @@ namespace {
       }
     }
 
+    // Transform the string input into emscripten_asm_const_*(str, args1, arg2)
+    // into an id. We emit a map of id => string contents, and emscripten
+    // wraps it up so that calling that id calls that function.
+    unsigned getAsmConstId(const Value *V) {
+      V = resolveFully(V);
+      const Constant *CI = cast<GlobalVariable>(V)->getInitializer();
+      const ConstantDataSequential *CDS = cast<ConstantDataSequential>(CI);
+      std::string code = CDS->getAsString();
+      unsigned id = AsmConsts.size();
+      AsmConsts[code] = id;
+      return id;
+    }
+
     // Test whether the given value is known to be an absolute value or one we turn into an absolute value
     bool isAbsolute(const Value *P) {
       if (const IntToPtrInst *ITP = dyn_cast<IntToPtrInst>(P)) {
@@ -2653,6 +2667,18 @@ void JSWriter::printModuleBody() {
     }
     Out << "\"_" << I->first << "\": \"" << utostr(I->second) << "\"";
   }
+  Out << "},";
+
+  Out << "\"asmConsts\": {";
+  first = true;
+  for (NameIntMap::const_iterator I = AsmConsts.begin(), E = AsmConsts.end(); I != E; ++I) {
+    if (first) {
+      first = false;
+    } else {
+      Out << ", ";
+    }
+    Out << "\"" << utostr(I->second) << "\": \"" << I->first.c_str() << "\"";
+  }
   Out << "}";
 
   Out << "\n}\n";