parse error details

4 files changed, 49 insertions, 23 deletions

diff --git a/src/parsing.h b/src/parsing.h
index 2104337a6..6745ad7cd 100644
--- a/src/parsing.h
+++ b/src/parsing.h
@@ -17,12 +17,15 @@
 #ifndef wasm_parsing_h
 #define wasm_parsing_h
 
+#include <ostream>
 #include <sstream>
+#include <string>
 
 #include "asmjs/shared-constants.h"
 #include "mixed_arena.h"
 #include "support/utilities.h"
 #include "wasm.h"
+#include "wasm-printing.h"
 
 namespace wasm {
 
@@ -162,6 +165,30 @@ inline Expression* parseConst(cashew::IString s, WasmType type, MixedArena& allo
   return ret;
 }
 
+struct ParseException {
+  std::string text;
+  size_t line, col;
+
+  ParseException() : text("unknown parse error"), line(-1), col(-1) {}
+  ParseException(std::string text) : text(text), line(-1), col(-1) {}
+  ParseException(std::string text, size_t line, size_t col) : text(text), line(line), col(col) {}
+
+  void dump(std::ostream& o) {
+    Colors::magenta(o);
+    o << "[";
+    Colors::red(o);
+    o << "parse exception: ";
+    Colors::green(o);
+    o << text;
+    if (line != size_t(-1)) {
+      Colors::normal(o);
+      o << " (at " << line << ":" << col << ")";
+    }
+    Colors::magenta(o);
+    o << "]";
+    Colors::normal(o);
+  }
+};
 
 } // namespace wasm
 
diff --git a/src/shell-interface.h b/src/shell-interface.h
index 5b6a64e79..b87460a48 100644
--- a/src/shell-interface.h
+++ b/src/shell-interface.h
@@ -29,7 +29,6 @@ namespace wasm {
 
 struct ExitException {};
 struct TrapException {};
-struct ParseException {};
 
 struct ShellExternalInterface : ModuleInstance::ExternalInterface {
   // The underlying memory can be accessed through unaligned pointers which
diff --git a/src/wasm-binary.h b/src/wasm-binary.h
index e49abe71e..bd78d9f9d 100644
--- a/src/wasm-binary.h
+++ b/src/wasm-binary.h
@@ -32,7 +32,7 @@
 #include "asm_v_wasm.h"
 #include "wasm-builder.h"
 #include "ast_utils.h"
-#include "shell-interface.h"
+#include "parsing.h"
 #include "wasm-validator.h"
 
 namespace wasm {
@@ -1226,7 +1226,7 @@ public:
   }
 
   uint8_t getInt8() {
-    if (!more()) throw ParseException();
+    if (!more()) throw ParseException("unexpected end of input");
     if (debug) std::cerr << "getInt8: " << (int)(uint8_t)input[pos] << " (at " << pos << ")" << std::endl;
     return input[pos++];
   }
@@ -1330,27 +1330,27 @@ public:
 
   void verifyInt8(int8_t x) {
     int8_t y = getInt8();
-    if (x != y) throw ParseException();
+    if (x != y) throw ParseException("surprising value", 0, pos);
   }
   void verifyInt16(int16_t x) {
     int16_t y = getInt16();
-    if (x != y) throw ParseException();
+    if (x != y) throw ParseException("surprising value", 0, pos);
   }
   void verifyInt32(int32_t x) {
     int32_t y = getInt32();
-    if (x != y) throw ParseException();
+    if (x != y) throw ParseException("surprising value", 0, pos);
   }
   void verifyInt64(int64_t x) {
     int64_t y = getInt64();
-    if (x != y) throw ParseException();
+    if (x != y) throw ParseException("surprising value", 0, pos);
   }
   void verifyFloat32(float x) {
     float y = getFloat32();
-    if (x != y) throw ParseException();
+    if (x != y) throw ParseException("surprising value", 0, pos);
   }
   void verifyFloat64(double x) {
     double y = getFloat64();
-    if (x != y) throw ParseException();
+    if (x != y) throw ParseException("surprising value", 0, pos);
   }
 
   void ungetInt8() {
diff --git a/src/wasm-s-parser.h b/src/wasm-s-parser.h
index e38c33ce6..e0f85227d 100644
--- a/src/wasm-s-parser.h
+++ b/src/wasm-s-parser.h
@@ -299,7 +299,7 @@ private:
         return;
       } else if (id == TYPE) {
         Name typeName = curr[1]->str();
-        if (!wasm.checkFunctionType(typeName)) throw ParseException();
+        if (!wasm.checkFunctionType(typeName)) throw ParseException("unknown function");
         FunctionType* type = wasm.getFunctionType(typeName);
         functionTypes[name] = type->result;
         return;
@@ -323,7 +323,7 @@ private:
     if (id == TABLE) return parseTable(curr);
     if (id == TYPE) return; // already done
     std::cerr << "bad module element " << id.str << '\n';
-    throw ParseException();
+    throw ParseException("unknown module element");
   }
 
   // function parsing state
@@ -343,7 +343,7 @@ private:
     } else {
       // index
       size_t offset = atoi(s.str().c_str());
-      if (offset >= functionNames.size()) throw ParseException();
+      if (offset >= functionNames.size()) throw ParseException("unknown function");
       return functionNames[offset];
     }
   }
@@ -413,7 +413,7 @@ private:
       } else if (id == TYPE) {
         Name name = curr[1]->str();
         type = name;
-        if (!wasm.checkFunctionType(name)) throw ParseException();
+        if (!wasm.checkFunctionType(name)) throw ParseException("unknown function");
         FunctionType* type = wasm.getFunctionType(name);
         result = type->result;
         for (size_t j = 0; j < type->params.size(); j++) {
@@ -468,7 +468,7 @@ private:
       if (str[1] == '6' && str[2] == '4' && (prefix || str[3] == 0)) return f64;
     }
     if (allowError) return none;
-    throw ParseException();
+    throw ParseException("unknown type");
     abort();
   }
 
@@ -477,7 +477,7 @@ public:
     return parseExpression(*s);
   }
 
-  #define abort_on(str) { std::cerr << "aborting on " << str << '\n'; throw ParseException(); }
+  #define abort_on(str) { throw ParseException(std::string("abort_on ") + str); }
 
   Expression* parseExpression(Element& s) {
     IString id = s[0]->str();
@@ -816,7 +816,7 @@ private:
 
   Expression* makeConst(Element& s, WasmType type) {
     auto ret = parseConst(s[1]->str(), type, allocator);
-    if (!ret) throw ParseException();
+    if (!ret) throw ParseException("bad const");
     return ret;
   }
 
@@ -850,9 +850,9 @@ private:
         ret->align = atoi(eq);
       } else if (str[0] == 'o') {
         uint64_t offset = atoll(eq);
-        if (offset > std::numeric_limits<uint32_t>::max()) throw ParseException();
+        if (offset > std::numeric_limits<uint32_t>::max()) throw ParseException("bad offset");
         ret->offset = (uint32_t)offset;
-      } else throw ParseException();
+      } else throw ParseException("bad load attribute");
       i++;
     }
     ret->ptr = parseExpression(s[i]);
@@ -888,7 +888,7 @@ private:
         ret->align = atoi(eq);
       } else if (str[0] == 'o') {
         ret->offset = atoi(eq);
-      } else throw ParseException();
+      } else throw ParseException("bad store attribute");
       i++;
     }
     ret->ptr = parseExpression(s[i]);
@@ -1136,7 +1136,7 @@ private:
   void parseExport(Element& s) {
     if (!s[2]->dollared() && !std::isdigit(s[2]->str()[0])) {
       assert(s[2]->str() == MEMORY);
-      if (!hasMemory) throw ParseException();
+      if (!hasMemory) throw ParseException("memory exported but no memory");
       wasm.memory.exportName = s[1]->str();
       return;
     }
@@ -1156,7 +1156,7 @@ private:
     }
     importCounter++;
     im->module = s[i++]->str();
-    if (!s[i]->isStr()) throw ParseException();
+    if (!s[i]->isStr()) throw ParseException("no name for import");
     im->base = s[i++]->str();
     std::unique_ptr<FunctionType> type = make_unique<FunctionType>();
     if (s.size() > i) {
@@ -1170,10 +1170,10 @@ private:
         type->result = stringToWasmType(params[1]->str());
       } else if (id == TYPE) {
         IString name = params[1]->str();
-        if (!wasm.checkFunctionType(name)) throw ParseException();
+        if (!wasm.checkFunctionType(name)) throw ParseException("bad function type for import");
         *type = *wasm.getFunctionType(name);
       } else {
-        throw ParseException();
+        throw ParseException("bad import element");
       }
       if (s.size() > i+1) {
         Element& result = *s[i+1];