From 8171be8a66ffe63cf4845552b1a901645d08affd Mon Sep 17 00:00:00 2001
From: Yury Delendik <ydelendik@mozilla.com>
Date: Wed, 26 Apr 2017 10:48:18 -0500
Subject: [PATCH] Extends wasm-as, wasm-dis and s2wasm to consume debug
 locations.

---
 src/asm2wasm.h                                |  4 +-
 src/passes/Print.cpp                          |  9 ++-
 src/s2wasm.h                                  | 27 +++++++--
 src/tools/wasm-as.cpp                         | 17 ++++++
 src/tools/wasm-dis.cpp                        | 13 +++++
 src/wasm-binary.h                             | 20 ++++++-
 src/wasm-s-parser.h                           | 20 ++++++-
 src/wasm.h                                    |  4 +-
 src/wasm/wasm-binary.cpp                      | 50 ++++++++++++++++
 src/wasm/wasm-s-parser.cpp                    | 58 +++++++++++++++++--
 test/debugInfo.fromasm                        | 25 ++++----
 test/debugInfo.fromasm.clamp                  | 25 ++++----
 test/debugInfo.fromasm.clamp.no-opts          | 29 +++++-----
 test/debugInfo.fromasm.clamp.no-opts.txtmap   | 22 ++++---
 test/debugInfo.fromasm.clamp.txtmap           | 14 ++++-
 test/debugInfo.fromasm.imprecise              | 25 ++++----
 test/debugInfo.fromasm.imprecise.no-opts      | 29 +++++-----
 ...debugInfo.fromasm.imprecise.no-opts.txtmap | 22 ++++---
 test/debugInfo.fromasm.imprecise.txtmap       | 13 ++++-
 test/debugInfo.fromasm.no-opts                | 29 +++++-----
 test/debugInfo.fromasm.no-opts.txtmap         | 22 ++++---
 test/debugInfo.fromasm.txtmap                 | 14 ++++-
 test/dot_s/debug.wast                         |  4 ++
 23 files changed, 360 insertions(+), 135 deletions(-)

diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index 16e7c95e1e9..b8439bdbf8d 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -1382,13 +1382,13 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
                 while (i < expressionStack.size()) {
                   exp = expressionStack[i];
                   if (debugLocations.count(exp) == 0) {
-                    debugLocations[exp] = { fileIndex, lineNumber };
+                    debugLocations[exp] = { fileIndex, lineNumber, 0 };
                     break;
                   }
                   i++;
                 }
               } else {
-                debugLocations[exp] = { fileIndex, lineNumber };
+                debugLocations[exp] = { fileIndex, lineNumber, 0 };
               }
               break;
             }
diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index 6aebd612bc9..95f60e5e2c3 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -45,6 +45,7 @@ struct PrintSExpression : public Visitor<PrintSExpression> {
 
   Module* currModule = nullptr;
   Function* currFunction = nullptr;
+  Function::DebugLocation lastPrintedLocation;
 
   PrintSExpression(std::ostream& o) : o(o) {
     setMinify(false);
@@ -58,8 +59,11 @@ struct PrintSExpression : public Visitor<PrintSExpression> {
       auto iter = debugLocations.find(curr);
       if (iter != debugLocations.end()) {
         auto fileName = currModule->debugInfoFileNames[iter->second.fileIndex];
-        o << ";; " << fileName << ":" << iter->second.lineNumber << '\n';
-        doIndent(o, indent);
+        if (lastPrintedLocation != iter->second) {
+          lastPrintedLocation = iter->second;
+          o << ";;@ " << fileName << ":" << iter->second.lineNumber << ":" << iter->second.columnNumber << '\n';
+          doIndent(o, indent);
+        }
       }
     }
     Visitor<PrintSExpression>::visit(curr);
@@ -599,6 +603,7 @@ struct PrintSExpression : public Visitor<PrintSExpression> {
   }
   void visitFunction(Function *curr) {
     currFunction = curr;
+    lastPrintedLocation = { 0, 0, 0 };
     printOpening(o, "func ", true);
     printName(curr->name);
     if (curr->type.is()) {
diff --git a/src/s2wasm.h b/src/s2wasm.h
index 6ba4750ec49..146e0bcfef2 100644
--- a/src/s2wasm.h
+++ b/src/s2wasm.h
@@ -44,6 +44,7 @@ class S2WasmBuilder {
   MixedArena* allocator;
   LinkerObject* linkerObj;
   std::unique_ptr<LinkerObject::SymbolInfo> symbolInfo;
+  std::unordered_map<uint32_t, uint32_t> fileIndexMap;
 
  public:
   S2WasmBuilder(const char* input, bool debug)
@@ -601,7 +602,9 @@ class S2WasmBuilder {
       size_t fileId = getInt();
       skipWhitespace();
       auto quoted = getQuoted();
-      WASM_UNUSED(fileId); WASM_UNUSED(quoted); // TODO: use the fileId and quoted
+      uint32_t index = wasm->debugInfoFileNames.size();
+      fileIndexMap[fileId] = index;
+      wasm->debugInfoFileNames.push_back(std::string(quoted.begin(), quoted.end()));
       s = strchr(s, '\n');
       return;
     }
@@ -665,22 +668,31 @@ class S2WasmBuilder {
 
     mustMatch(":");
 
+    Function::DebugLocation debugLocation = {0,0,0};
+    bool useDebugLocation = false;
     auto recordFile = [&]() {
       if (debug) dump("file");
       size_t fileId = getInt();
       skipWhitespace();
       auto quoted = getQuoted();
-      WASM_UNUSED(fileId); WASM_UNUSED(quoted); // TODO: use the fileId and quoted
+      uint32_t index = wasm->debugInfoFileNames.size();
+      fileIndexMap[fileId] = index;
+      wasm->debugInfoFileNames.push_back(std::string(quoted.begin(), quoted.end()));
       s = strchr(s, '\n');
     };
     auto recordLoc = [&]() {
       if (debug) dump("loc");
       size_t fileId = getInt();
       skipWhitespace();
-      size_t row = getInt();
+      uint32_t row = getInt();
       skipWhitespace();
-      size_t column = getInt();
-      WASM_UNUSED(fileId); WASM_UNUSED(row); WASM_UNUSED(column); // TODO: use the fileId, row and column
+      uint32_t column = getInt();
+      auto iter = fileIndexMap.find(fileId);
+      if (iter == fileIndexMap.end()) {
+        abort_on("idx");
+      }
+      useDebugLocation = true;
+      debugLocation = {iter->second, row, column};
       s = strchr(s, '\n');
     };
     auto recordLabel = [&]() {
@@ -746,7 +758,10 @@ class S2WasmBuilder {
     // parse body
     func->body = allocator->alloc<Block>();
     std::vector<Expression*> bstack;
-    auto addToBlock = [&bstack](Expression* curr) {
+    auto addToBlock = [&](Expression* curr) {
+      if (useDebugLocation) {
+        func->debugLocations[curr] = debugLocation;
+      }
       Expression* last = bstack.back();
       if (last->is<Loop>()) {
         last = last->cast<Loop>()->body;
diff --git a/src/tools/wasm-as.cpp b/src/tools/wasm-as.cpp
index 5bdf74b029b..c96e4d72340 100644
--- a/src/tools/wasm-as.cpp
+++ b/src/tools/wasm-as.cpp
@@ -30,6 +30,8 @@ using namespace wasm;
 int main(int argc, const char *argv[]) {
   bool debugInfo = false;
   std::string symbolMap;
+  std::string binaryMapFilename;
+  std::string binaryMapUrl;
   Options options("wasm-as", "Assemble a .wast (WebAssembly text format) into a .wasm (WebAssembly binary format)");
   options.extra["validate"] = "wasm";
   options
@@ -51,6 +53,12 @@ int main(int argc, const char *argv[]) {
       .add("--debuginfo", "-g", "Emit names section and debug info",
            Options::Arguments::Zero,
            [&](Options *o, const std::string &arguments) { debugInfo = true; })
+      .add("--binarymap-file", "-bm", "Emit binary map to the specified file",
+           Options::Arguments::One,
+           [&binaryMapFilename](Options *o, const std::string &argument) { binaryMapFilename = argument; })
+      .add("--binarymap-url", "-bu", "Use specified string as binary map URL",
+           Options::Arguments::One,
+           [&binaryMapUrl](Options *o, const std::string &argument) { binaryMapUrl = argument; })
       .add("--symbolmap", "-s", "Emit a symbol map (indexes => names)",
            Options::Arguments::One,
            [&](Options *o, const std::string &argument) { symbolMap = argument; })
@@ -87,12 +95,21 @@ int main(int argc, const char *argv[]) {
   BufferWithRandomAccess buffer(options.debug);
   WasmBinaryWriter writer(&wasm, buffer, options.debug);
   writer.setNamesSection(debugInfo);
+  std::unique_ptr<std::ofstream> binaryMapStream = nullptr;
+  if (binaryMapFilename.size()) {
+    binaryMapStream = make_unique<std::ofstream>();
+    binaryMapStream->open(binaryMapFilename);
+    writer.setBinaryMap(binaryMapStream.get(), binaryMapUrl);
+  }
   if (symbolMap.size() > 0) writer.setSymbolMap(symbolMap);
   writer.write();
 
   if (options.debug) std::cerr << "writing to output..." << std::endl;
   Output output(options.extra["output"], Flags::Binary, options.debug ? Flags::Debug : Flags::Release);
   buffer.writeTo(output);
+  if (binaryMapStream) {
+    binaryMapStream->close();
+  }
 
   if (options.debug) std::cerr << "Done." << std::endl;
 }
diff --git a/src/tools/wasm-dis.cpp b/src/tools/wasm-dis.cpp
index 93c28691362..c33b4d333e0 100644
--- a/src/tools/wasm-dis.cpp
+++ b/src/tools/wasm-dis.cpp
@@ -28,6 +28,7 @@ using namespace cashew;
 using namespace wasm;
 
 int main(int argc, const char *argv[]) {
+  std::string binaryMapFilename;
   Options options("wasm-dis", "Un-assemble a .wasm (WebAssembly binary format) into a .wast (WebAssembly text format)");
   options.add("--output", "-o", "Output file (stdout if not specified)",
               Options::Arguments::One,
@@ -35,6 +36,9 @@ int main(int argc, const char *argv[]) {
                 o->extra["output"] = argument;
                 Colors::disable();
               })
+      .add("--binarymap-file", "-bm", "Consume binary map from the specified file to add location information",
+           Options::Arguments::One,
+           [&binaryMapFilename](Options *o, const std::string &argument) { binaryMapFilename = argument; })
       .add_positional("INFILE", Options::Arguments::One,
                       [](Options *o, const std::string &argument) {
                         o->extra["infile"] = argument;
@@ -46,8 +50,17 @@ int main(int argc, const char *argv[]) {
   if (options.debug) std::cerr << "parsing binary..." << std::endl;
   Module wasm;
   try {
+    std::unique_ptr<std::ifstream> binaryMapStream;
     WasmBinaryBuilder parser(wasm, input, options.debug);
+    if (binaryMapFilename.size()) {
+        binaryMapStream = make_unique<std::ifstream>();
+        binaryMapStream->open(binaryMapFilename);
+        parser.setDebugLocations(binaryMapStream.get());
+    }
     parser.read();
+    if (binaryMapStream) {
+        binaryMapStream->close();
+    }
   } catch (ParseException& p) {
     p.dump(std::cerr);
     Fatal() << "error in parsing wasm binary";
diff --git a/src/wasm-binary.h b/src/wasm-binary.h
index 27ed553a4fa..a6dcba8e31d 100644
--- a/src/wasm-binary.h
+++ b/src/wasm-binary.h
@@ -615,15 +615,17 @@ class WasmBinaryWriter : public Visitor<WasmBinaryWriter, void> {
 
   void recurse(Expression*& curr);
   std::vector<Name> breakStack;
+  Function::DebugLocation lastDebugLocation;
 
   void visit(Expression* curr) {
     if (binaryMap && currFunction) {
       // Dump the binaryMap debug info
       auto& debugLocations = currFunction->debugLocations;
       auto iter = debugLocations.find(curr);
-      if (iter != debugLocations.end()) {
+      if (iter != debugLocations.end() && iter->second != lastDebugLocation) {
+        lastDebugLocation = iter->second;
         auto fileName = wasm->debugInfoFileNames[iter->second.fileIndex];
-        *binaryMap << o.size() << ":" << fileName << ":" <<iter->second.lineNumber << '\n';
+        *binaryMap << o.size() << ":" << fileName << ":" << iter->second.lineNumber << ":" << iter->second.columnNumber << '\n';
       }
     }
     Visitor<WasmBinaryWriter>::visit(curr);
@@ -663,6 +665,8 @@ class WasmBinaryBuilder {
   MixedArena& allocator;
   std::vector<char>& input;
   bool debug;
+  std::istream* binaryMap;
+  std::pair<uint32_t, Function::DebugLocation> nextDebugLocation;
 
   size_t pos = 0;
   Index startIndex = -1;
@@ -670,7 +674,7 @@ class WasmBinaryBuilder {
   std::set<BinaryConsts::Section> seenSections;
 
 public:
-  WasmBinaryBuilder(Module& wasm, std::vector<char>& input, bool debug) : wasm(wasm), allocator(wasm.allocator), input(input), debug(debug) {}
+  WasmBinaryBuilder(Module& wasm, std::vector<char>& input, bool debug) : wasm(wasm), allocator(wasm.allocator), input(input), debug(debug), binaryMap(nullptr), nextDebugLocation(0, {0,0,0})  {}
 
   void read();
   void readUserSection(size_t payloadLen);
@@ -759,6 +763,16 @@ class WasmBinaryBuilder {
   void readTableElements();
   void readNames(size_t);
 
+  // Debug information reading helpers
+  void setDebugLocations(std::istream* binaryMap_) {
+      binaryMap = binaryMap_;
+      readNextDebugLocation();
+  }
+  bool useDebugLocation;
+  Function::DebugLocation debugLocation;
+  std::unordered_map<std::string, Index> debugInfoFileIndices;
+  void readNextDebugLocation();
+
   // AST reading
   int depth = 0; // only for debugging
 
diff --git a/src/wasm-s-parser.h b/src/wasm-s-parser.h
index be1f6b6999f..4332f74af45 100644
--- a/src/wasm-s-parser.h
+++ b/src/wasm-s-parser.h
@@ -28,6 +28,16 @@
 
 namespace wasm {
 
+class SourceLocation
+{
+public:
+  std::string filename;
+  uint32_t line;
+  uint32_t column;
+  SourceLocation(const std::string& filename_, uint32_t line_, uint32_t column_ = 0)
+   : filename(filename_), line(line_), column(column_) {}
+};
+
 //
 // An element in an S-Expression: a list or a string
 //
@@ -41,7 +51,7 @@ class Element {
   bool quoted_;
 
 public:
-  Element(MixedArena& allocator) : isList_(true), list_(allocator), line(-1), col(-1) {}
+  Element(MixedArena& allocator) : isList_(true), list_(allocator), line(-1), col(-1), loc(nullptr) {}
 
   bool isList() { return isList_; }
   bool isStr() { return !isList_; }
@@ -49,6 +59,7 @@ class Element {
   bool quoted() { return isStr() && quoted_; }
 
   size_t line, col;
+  SourceLocation* loc;
 
   // list methods
   List& list();
@@ -61,14 +72,13 @@ class Element {
   cashew::IString str();
   const char* c_str();
   Element* setString(cashew::IString str__, bool dollared__, bool quoted__);
-  Element* setMetadata(size_t line_, size_t col_);
+  Element* setMetadata(size_t line_, size_t col_, SourceLocation* loc_);
 
   // printing
   friend std::ostream& operator<<(std::ostream& o, Element& e);
   void dump();
 };
 
-
 //
 // Generic S-Expression parsing into lists
 //
@@ -76,6 +86,7 @@ class SExpressionParser {
   char* input;
   size_t line;
   char* lineStart;
+  SourceLocation* loc;
 
   MixedArena allocator;
 
@@ -87,6 +98,7 @@ class SExpressionParser {
 private:
   Element* parse();
   void skipWhitespace();
+  void parseDebugLocation();
   Element* parseString();
 };
 
@@ -102,6 +114,7 @@ class SExpressionWasmBuilder {
   int functionCounter;
   int globalCounter;
   std::map<Name, WasmType> functionTypes; // we need to know function return types before we parse their contents
+  std::unordered_map<std::string, Index> debugInfoFileIndices;
 
 public:
   // Assumes control of and modifies the input.
@@ -147,6 +160,7 @@ class SExpressionWasmBuilder {
   Expression* parseExpression(Element& s);
 
 private:
+  Expression* makeExpression(Element& s);
   Expression* makeBinary(Element& s, BinaryOp op, WasmType type);
   Expression* makeUnary(Element& s, UnaryOp op, WasmType type);
   Expression* makeSelect(Element& s);
diff --git a/src/wasm.h b/src/wasm.h
index 3caab9dbc52..dba08d92ead 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -527,7 +527,9 @@ class Function {
   std::map<Name, Index> localIndices;
 
   struct DebugLocation {
-    uint32_t fileIndex, lineNumber;
+    uint32_t fileIndex, lineNumber, columnNumber;
+    bool operator==(const DebugLocation& other) const { return fileIndex == other.fileIndex && lineNumber == other.lineNumber && columnNumber == other.columnNumber; }
+    bool operator!=(const DebugLocation& other) const { return !(*this == other); }
   };
   std::unordered_map<Expression*, DebugLocation> debugLocations;
 
diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index 47f1a925797..f3697048f8d 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -238,6 +238,7 @@ void WasmBinaryWriter::writeFunctions() {
     size_t start = o.size();
     Function* function = wasm->functions[i].get();
     currFunction = function;
+    lastDebugLocation = {0, 0, 0};
     mappedLocals.clear();
     numLocalsByType.clear();
     if (debug) std::cerr << "writing" << function->name << std::endl;
@@ -1353,6 +1354,7 @@ void WasmBinaryBuilder::readFunctions() {
       // process the function body
       if (debug) std::cerr << "processing function: " << i << std::endl;
       nextLabel = 0;
+      useDebugLocation = false;
       breaksToReturn = false;
       // process body
       assert(breakStack.empty());
@@ -1400,6 +1402,43 @@ void WasmBinaryBuilder::readExports() {
   }
 }
 
+void WasmBinaryBuilder::readNextDebugLocation() {
+  if (binaryMap) {
+    std::string line;
+    while (std::getline(*binaryMap, line)) {
+      auto pos = line.begin();
+      while (pos < line.end() && pos[0] != ':') pos++;
+      if (pos == line.end()) continue;
+      uint32_t position = atoi(std::string(line.begin(), pos).c_str());
+      auto filenameStart = ++pos;
+      while (pos < line.end() && pos[0] != ':') pos++;
+      if (pos == line.end()) continue;
+      std::string file(filenameStart, pos);
+      auto iter = debugInfoFileIndices.find(file);
+      if (iter == debugInfoFileIndices.end()) {
+        Index index = wasm.debugInfoFileNames.size();
+        wasm.debugInfoFileNames.push_back(file);
+        debugInfoFileIndices[file] = index;
+      }
+      uint32_t fileIndex = debugInfoFileIndices[file];
+      auto lineNumberStart = ++pos;
+      while (pos < line.end() && pos[0] != ':') pos++;
+      if (pos == line.end()) {
+        // old format
+        uint32_t lineNumber = atoi(std::string(lineNumberStart, line.end()).c_str());
+        nextDebugLocation = {position, {fileIndex, lineNumber, 0}};
+        return;
+      }
+      uint32_t lineNumber = atoi(std::string(lineNumberStart, pos).c_str());
+      auto columnNumberStart = ++pos;
+      uint32_t columnNumber = atoi(std::string(columnNumberStart, line.end()).c_str());
+
+      nextDebugLocation = {position, {fileIndex, lineNumber, columnNumber}};
+      return;
+    }
+    nextDebugLocation.first = 0;
+  }
+}
 Expression* WasmBinaryBuilder::readExpression() {
   assert(depth == 0);
   processExpressions();
@@ -1638,6 +1677,15 @@ BinaryConsts::ASTNodes WasmBinaryBuilder::readExpression(Expression*& curr) {
     throw ParseException("Reached function end without seeing End opcode");
   }
   if (debug) std::cerr << "zz recurse into " << ++depth << " at " << pos << std::endl;
+  if (nextDebugLocation.first) {
+      while (nextDebugLocation.first && nextDebugLocation.first <= pos) {
+        if (nextDebugLocation.first < pos)
+          std::cerr << "skipping debug location info for " << nextDebugLocation.first << std::endl;
+        debugLocation = nextDebugLocation.second;
+        useDebugLocation = currFunction; // using only for function expressions
+        readNextDebugLocation();
+      }
+  }
   uint8_t code = getInt8();
   if (debug) std::cerr << "readExpression seeing " << (int)code << std::endl;
   switch (code) {
@@ -1672,6 +1720,8 @@ BinaryConsts::ASTNodes WasmBinaryBuilder::readExpression(Expression*& curr) {
       throw ParseException("bad node code " + std::to_string(code));
     }
   }
+  if (useDebugLocation && curr)
+      currFunction->debugLocations[curr] = debugLocation;
   if (debug) std::cerr << "zz recurse from " << depth-- << " at " << pos << std::endl;
   return BinaryConsts::ASTNodes(code);
 }
diff --git a/src/wasm/wasm-s-parser.cpp b/src/wasm/wasm-s-parser.cpp
index 9b053d5b8ce..2c78ac93691 100644
--- a/src/wasm/wasm-s-parser.cpp
+++ b/src/wasm/wasm-s-parser.cpp
@@ -71,9 +71,10 @@ Element* Element::setString(IString str__, bool dollared__, bool quoted__) {
   return this;
 }
 
-Element* Element::setMetadata(size_t line_, size_t col_) {
+Element* Element::setMetadata(size_t line_, size_t col_, SourceLocation* loc_) {
   line = line_;
   col = col_;
+  loc = loc_;
   return this;
 }
 
@@ -93,7 +94,7 @@ void Element::dump() {
 }
 
 
-SExpressionParser::SExpressionParser(char* input) : input(input) {
+SExpressionParser::SExpressionParser(char* input) : input(input), loc(nullptr) {
   root = nullptr;
   line = 1;
   lineStart = input;
@@ -104,6 +105,7 @@ SExpressionParser::SExpressionParser(char* input) : input(input) {
 
 Element* SExpressionParser::parse() {
   std::vector<Element *> stack;
+  std::vector<SourceLocation*> stackLocs;
   Element *curr = allocator.alloc<Element>();
   while (1) {
     skipWhitespace();
@@ -111,7 +113,9 @@ Element* SExpressionParser::parse() {
     if (input[0] == '(') {
       input++;
       stack.push_back(curr);
-      curr = allocator.alloc<Element>()->setMetadata(line, input - lineStart - 1);
+      curr = allocator.alloc<Element>()->setMetadata(line, input - lineStart - 1, loc);
+      stackLocs.push_back(loc);
+      assert(stack.size() == stackLocs.size());
     } else if (input[0] == ')') {
       input++;
       auto last = curr;
@@ -119,7 +123,10 @@ Element* SExpressionParser::parse() {
         throw ParseException("s-expr stack empty");
       }
       curr = stack.back();
+      assert(stack.size() == stackLocs.size());
       stack.pop_back();
+      loc = stackLocs.back();
+      stackLocs.pop_back();
       curr->list().push_back(last);
     } else {
       curr->list().push_back(parseString());
@@ -129,6 +136,27 @@ Element* SExpressionParser::parse() {
   return curr;
 }
 
+void SExpressionParser::parseDebugLocation() {
+  // Extracting debug location (if valid)
+  char* debugLoc = input + 3; // skipping ";;@"
+  while (debugLoc[0] && debugLoc[0] == ' ') debugLoc++;
+  char* debugLocEnd = debugLoc;
+  while (debugLocEnd[0] && debugLocEnd[0] != '\n') debugLocEnd++;
+  char* pos = debugLoc;
+  while (pos < debugLocEnd && pos[0] != ':') pos++;
+  if (pos >= debugLocEnd)
+    return; // no line number
+  std::string name(debugLoc, pos);
+  char* lineStart = ++pos;
+  while (pos < debugLocEnd && pos[0] != ':') pos++;
+  std::string lineStr(lineStart, pos);
+  if (pos >= debugLocEnd)
+    return; // no column number
+  std::string colStr(++pos, debugLocEnd);
+  void* buf = allocator.allocSpace(sizeof(SourceLocation));
+  loc = new (buf) SourceLocation(name, atoi(lineStr.c_str()), atoi(colStr.c_str()));
+}
+
 void SExpressionParser::skipWhitespace() {
   while (1) {
     while (isspace(input[0])) {
@@ -139,6 +167,9 @@ void SExpressionParser::skipWhitespace() {
       input++;
     }
     if (input[0] == ';' && input[1] == ';') {
+      if (input[2] == '@') {
+        parseDebugLocation();
+      }
       while (input[0] && input[0] != '\n') input++;
       line++;
       lineStart = ++input;
@@ -198,13 +229,13 @@ Element* SExpressionParser::parseString() {
       input++;
     }
     input++;
-    return allocator.alloc<Element>()->setString(IString(str.c_str(), false), dollared, true)->setMetadata(line, start - lineStart);
+    return allocator.alloc<Element>()->setString(IString(str.c_str(), false), dollared, true)->setMetadata(line, start - lineStart, loc);
   }
   while (input[0] && !isspace(input[0]) && input[0] != ')' && input[0] != '(' && input[0] != ';') input++;
   if (start == input) throw ParseException("expected string", line, input - lineStart);
   char temp = input[0];
   input[0] = 0;
-  auto ret = allocator.alloc<Element>()->setString(IString(start, false), dollared, false)->setMetadata(line, start - lineStart);
+  auto ret = allocator.alloc<Element>()->setString(IString(start, false), dollared, false)->setMetadata(line, start - lineStart, loc);
   input[0] = temp;
   return ret;
 }
@@ -583,6 +614,23 @@ WasmType SExpressionWasmBuilder::stringToWasmType(const char* str, bool allowErr
 }
 
 Expression* SExpressionWasmBuilder::parseExpression(Element& s) {
+  Expression* result = makeExpression(s);
+  if (s.loc) {
+    std::string& file = s.loc->filename;
+    auto& debugInfoFileNames = wasm.debugInfoFileNames;
+    auto iter = debugInfoFileIndices.find(file);
+    if (iter == debugInfoFileIndices.end()) {
+      Index index = debugInfoFileNames.size();
+      debugInfoFileNames.push_back(file);
+      debugInfoFileIndices[file] = index;
+    }
+    uint32_t fileIndex = debugInfoFileIndices[file];
+    currFunction->debugLocations[result] = {fileIndex, s.loc->line, s.loc->column};
+  }
+  return result;
+}
+
+Expression* SExpressionWasmBuilder::makeExpression(Element& s) {
   IString id = s[0]->str();
   const char *str = id.str;
   const char *dot = strchr(str, '.');
diff --git a/test/debugInfo.fromasm b/test/debugInfo.fromasm
index 84fb4aece99..7aa584c4371 100644
--- a/test/debugInfo.fromasm
+++ b/test/debugInfo.fromasm
@@ -11,21 +11,21 @@
  (export "fib" (func $fib))
  (export "switch_reach" (func $switch_reach))
  (func $add (param $0 i32) (param $1 i32) (result i32)
-  ;; tests/other_file.cpp:314159
+  ;;@ tests/other_file.cpp:314159:0
   (i32.add
    (get_local $1)
    (get_local $1)
   )
  )
  (func $ret (param $0 i32) (result i32)
-  ;; return.cpp:50
+  ;;@ return.cpp:50:0
   (set_local $0
    (i32.shl
     (get_local $0)
     (i32.const 1)
    )
   )
-  ;; return.cpp:100
+  ;;@ return.cpp:100:0
   (i32.add
    (get_local $0)
    (i32.const 1)
@@ -42,21 +42,21 @@
   )
  )
  (func $opts (param $0 i32) (param $1 i32) (result i32)
-  ;; even-opted.cpp:1
+  ;;@ even-opted.cpp:1:0
   (set_local $0
    (i32.add
     (get_local $0)
     (get_local $1)
    )
   )
-  ;; even-opted.cpp:2
+  ;;@ even-opted.cpp:2:0
   (set_local $1
    (i32.shr_s
     (get_local $1)
     (get_local $0)
    )
   )
-  ;; even-opted.cpp:3
+  ;;@ even-opted.cpp:3:0
   (i32.add
    (call $i32s-rem
     (get_local $0)
@@ -71,7 +71,7 @@
   (local $3 i32)
   (local $4 i32)
   (if
-   ;; fib.c:3
+   ;;@ fib.c:3:0
    (i32.gt_s
     (get_local $0)
     (i32.const 0)
@@ -91,21 +91,21 @@
     (set_local $1
      (i32.const 1)
     )
-    ;; fib.c:8
+    ;;@ fib.c:8:0
     (return
      (get_local $1)
     )
    )
   )
   (loop $while-in
-   ;; fib.c:4
+   ;;@ fib.c:4:0
    (set_local $1
     (i32.add
      (get_local $3)
      (get_local $4)
     )
    )
-   ;; fib.c:3
+   ;;@ fib.c:3:0
    (set_local $2
     (i32.add
      (get_local $2)
@@ -113,7 +113,6 @@
     )
    )
    (if
-    ;; fib.c:3
     (i32.ne
      (get_local $2)
      (get_local $0)
@@ -129,7 +128,7 @@
     )
    )
   )
-  ;; fib.c:8
+  ;;@ fib.c:8:0
   (get_local $1)
  )
  (func $switch_reach (param $0 i32) (result i32)
@@ -189,7 +188,7 @@
     (get_local $0)
    )
   )
-  ;; /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950
+  ;;@ /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
   (get_local $1)
  )
 )
diff --git a/test/debugInfo.fromasm.clamp b/test/debugInfo.fromasm.clamp
index 84fb4aece99..7aa584c4371 100644
--- a/test/debugInfo.fromasm.clamp
+++ b/test/debugInfo.fromasm.clamp
@@ -11,21 +11,21 @@
  (export "fib" (func $fib))
  (export "switch_reach" (func $switch_reach))
  (func $add (param $0 i32) (param $1 i32) (result i32)
-  ;; tests/other_file.cpp:314159
+  ;;@ tests/other_file.cpp:314159:0
   (i32.add
    (get_local $1)
    (get_local $1)
   )
  )
  (func $ret (param $0 i32) (result i32)
-  ;; return.cpp:50
+  ;;@ return.cpp:50:0
   (set_local $0
    (i32.shl
     (get_local $0)
     (i32.const 1)
    )
   )
-  ;; return.cpp:100
+  ;;@ return.cpp:100:0
   (i32.add
    (get_local $0)
    (i32.const 1)
@@ -42,21 +42,21 @@
   )
  )
  (func $opts (param $0 i32) (param $1 i32) (result i32)
-  ;; even-opted.cpp:1
+  ;;@ even-opted.cpp:1:0
   (set_local $0
    (i32.add
     (get_local $0)
     (get_local $1)
    )
   )
-  ;; even-opted.cpp:2
+  ;;@ even-opted.cpp:2:0
   (set_local $1
    (i32.shr_s
     (get_local $1)
     (get_local $0)
    )
   )
-  ;; even-opted.cpp:3
+  ;;@ even-opted.cpp:3:0
   (i32.add
    (call $i32s-rem
     (get_local $0)
@@ -71,7 +71,7 @@
   (local $3 i32)
   (local $4 i32)
   (if
-   ;; fib.c:3
+   ;;@ fib.c:3:0
    (i32.gt_s
     (get_local $0)
     (i32.const 0)
@@ -91,21 +91,21 @@
     (set_local $1
      (i32.const 1)
     )
-    ;; fib.c:8
+    ;;@ fib.c:8:0
     (return
      (get_local $1)
     )
    )
   )
   (loop $while-in
-   ;; fib.c:4
+   ;;@ fib.c:4:0
    (set_local $1
     (i32.add
      (get_local $3)
      (get_local $4)
     )
    )
-   ;; fib.c:3
+   ;;@ fib.c:3:0
    (set_local $2
     (i32.add
      (get_local $2)
@@ -113,7 +113,6 @@
     )
    )
    (if
-    ;; fib.c:3
     (i32.ne
      (get_local $2)
      (get_local $0)
@@ -129,7 +128,7 @@
     )
    )
   )
-  ;; fib.c:8
+  ;;@ fib.c:8:0
   (get_local $1)
  )
  (func $switch_reach (param $0 i32) (result i32)
@@ -189,7 +188,7 @@
     (get_local $0)
    )
   )
-  ;; /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950
+  ;;@ /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
   (get_local $1)
  )
 )
diff --git a/test/debugInfo.fromasm.clamp.no-opts b/test/debugInfo.fromasm.clamp.no-opts
index 9e3050695ed..054226a3a3c 100644
--- a/test/debugInfo.fromasm.clamp.no-opts
+++ b/test/debugInfo.fromasm.clamp.no-opts
@@ -11,15 +11,15 @@
  (export "fib" (func $fib))
  (export "switch_reach" (func $switch_reach))
  (func $add (param $x i32) (param $y i32) (result i32)
-  ;; tests/hello_world.c:5
+  ;;@ tests/hello_world.c:5:0
   (set_local $x
    (get_local $x)
   )
-  ;; tests/hello_world.c:6
+  ;;@ tests/hello_world.c:6:0
   (set_local $y
    (get_local $y)
   )
-  ;; tests/other_file.cpp:314159
+  ;;@ tests/other_file.cpp:314159:0
   (set_local $x
    (get_local $y)
   )
@@ -31,14 +31,14 @@
   )
  )
  (func $ret (param $x i32) (result i32)
-  ;; return.cpp:50
+  ;;@ return.cpp:50:0
   (set_local $x
    (i32.shl
     (get_local $x)
     (i32.const 1)
    )
   )
-  ;; return.cpp:100
+  ;;@ return.cpp:100:0
   (return
    (i32.add
     (get_local $x)
@@ -59,21 +59,21 @@
   )
  )
  (func $opts (param $x i32) (param $y i32) (result i32)
-  ;; even-opted.cpp:1
+  ;;@ even-opted.cpp:1:0
   (set_local $x
    (i32.add
     (get_local $x)
     (get_local $y)
    )
   )
-  ;; even-opted.cpp:2
+  ;;@ even-opted.cpp:2:0
   (set_local $y
    (i32.shr_s
     (get_local $y)
     (get_local $x)
    )
   )
-  ;; even-opted.cpp:3
+  ;;@ even-opted.cpp:3:0
   (set_local $x
    (call $i32s-rem
     (get_local $x)
@@ -102,7 +102,7 @@
   (set_local $sp
    (get_global $STACKTOP)
   )
-  ;; fib.c:3
+  ;;@ fib.c:3:0
   (set_local $$1
    (i32.gt_s
     (get_local $$0)
@@ -126,7 +126,7 @@
     (set_local $$$0$lcssa
      (i32.const 1)
     )
-    ;; fib.c:8
+    ;;@ fib.c:8:0
     (return
      (get_local $$$0$lcssa)
     )
@@ -134,21 +134,20 @@
   )
   (loop $while-in
    (block $while-out
-    ;; fib.c:4
+    ;;@ fib.c:4:0
     (set_local $$2
      (i32.add
       (get_local $$$019)
       (get_local $$$01518)
      )
     )
-    ;; fib.c:3
+    ;;@ fib.c:3:0
     (set_local $$3
      (i32.add
       (get_local $$$01617)
       (i32.const 1)
      )
     )
-    ;; fib.c:3
     (set_local $$exitcond
      (i32.eq
       (get_local $$3)
@@ -181,7 +180,7 @@
     (br $while-in)
    )
   )
-  ;; fib.c:8
+  ;;@ fib.c:8:0
   (return
    (get_local $$$0$lcssa)
   )
@@ -278,7 +277,7 @@
     (get_local $$p)
    )
   )
-  ;; /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950
+  ;;@ /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
   (return
    (get_local $$rc$0)
   )
diff --git a/test/debugInfo.fromasm.clamp.no-opts.txtmap b/test/debugInfo.fromasm.clamp.no-opts.txtmap
index eec2e7bd354..f7b8c313154 100644
--- a/test/debugInfo.fromasm.clamp.no-opts.txtmap
+++ b/test/debugInfo.fromasm.clamp.no-opts.txtmap
@@ -1,8 +1,14 @@
-164:tests/hello_world.c:5
-168:tests/hello_world.c:6
-172:tests/other_file.cpp:314159
-194:return.cpp:50
-201:return.cpp:100
-241:even-opted.cpp:1
-248:even-opted.cpp:2
-255:even-opted.cpp:3
+199:tests/hello_world.c:5:0
+203:tests/hello_world.c:6:0
+207:tests/other_file.cpp:314159:0
+229:return.cpp:50:0
+236:return.cpp:100:0
+275:even-opted.cpp:1:0
+282:even-opted.cpp:2:0
+289:even-opted.cpp:3:0
+321:fib.c:3:0
+349:fib.c:8:0
+357:fib.c:4:0
+364:fib.c:3:0
+410:fib.c:8:0
+556:/tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
diff --git a/test/debugInfo.fromasm.clamp.txtmap b/test/debugInfo.fromasm.clamp.txtmap
index bb25b4d8d30..5ab814a0d4a 100644
--- a/test/debugInfo.fromasm.clamp.txtmap
+++ b/test/debugInfo.fromasm.clamp.txtmap
@@ -1,2 +1,12 @@
-211:even-opted.cpp:2
-223:even-opted.cpp:3
+185:tests/other_file.cpp:314159:0
+199:return.cpp:50:0
+206:return.cpp:100:0
+241:even-opted.cpp:1:0
+248:even-opted.cpp:2:0
+255:even-opted.cpp:3:0
+276:fib.c:3:0
+300:fib.c:8:0
+306:fib.c:4:0
+313:fib.c:3:0
+339:fib.c:8:0
+436:/tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
diff --git a/test/debugInfo.fromasm.imprecise b/test/debugInfo.fromasm.imprecise
index 4919d624dab..638911cfc1c 100644
--- a/test/debugInfo.fromasm.imprecise
+++ b/test/debugInfo.fromasm.imprecise
@@ -10,42 +10,42 @@
  (export "fib" (func $fib))
  (export "switch_reach" (func $switch_reach))
  (func $add (param $0 i32) (param $1 i32) (result i32)
-  ;; tests/other_file.cpp:314159
+  ;;@ tests/other_file.cpp:314159:0
   (i32.add
    (get_local $1)
    (get_local $1)
   )
  )
  (func $ret (param $0 i32) (result i32)
-  ;; return.cpp:50
+  ;;@ return.cpp:50:0
   (set_local $0
    (i32.shl
     (get_local $0)
     (i32.const 1)
    )
   )
-  ;; return.cpp:100
+  ;;@ return.cpp:100:0
   (i32.add
    (get_local $0)
    (i32.const 1)
   )
  )
  (func $opts (param $0 i32) (param $1 i32) (result i32)
-  ;; even-opted.cpp:1
+  ;;@ even-opted.cpp:1:0
   (set_local $0
    (i32.add
     (get_local $0)
     (get_local $1)
    )
   )
-  ;; even-opted.cpp:2
+  ;;@ even-opted.cpp:2:0
   (set_local $1
    (i32.shr_s
     (get_local $1)
     (get_local $0)
    )
   )
-  ;; even-opted.cpp:3
+  ;;@ even-opted.cpp:3:0
   (i32.add
    (i32.rem_s
     (get_local $0)
@@ -60,7 +60,7 @@
   (local $3 i32)
   (local $4 i32)
   (if
-   ;; fib.c:3
+   ;;@ fib.c:3:0
    (i32.gt_s
     (get_local $0)
     (i32.const 0)
@@ -80,21 +80,21 @@
     (set_local $1
      (i32.const 1)
     )
-    ;; fib.c:8
+    ;;@ fib.c:8:0
     (return
      (get_local $1)
     )
    )
   )
   (loop $while-in
-   ;; fib.c:4
+   ;;@ fib.c:4:0
    (set_local $1
     (i32.add
      (get_local $3)
      (get_local $4)
     )
    )
-   ;; fib.c:3
+   ;;@ fib.c:3:0
    (set_local $2
     (i32.add
      (get_local $2)
@@ -102,7 +102,6 @@
     )
    )
    (if
-    ;; fib.c:3
     (i32.ne
      (get_local $2)
      (get_local $0)
@@ -118,7 +117,7 @@
     )
    )
   )
-  ;; fib.c:8
+  ;;@ fib.c:8:0
   (get_local $1)
  )
  (func $switch_reach (param $0 i32) (result i32)
@@ -178,7 +177,7 @@
     (get_local $0)
    )
   )
-  ;; /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950
+  ;;@ /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
   (get_local $1)
  )
 )
diff --git a/test/debugInfo.fromasm.imprecise.no-opts b/test/debugInfo.fromasm.imprecise.no-opts
index 4bea2c35520..1ec751ef4d0 100644
--- a/test/debugInfo.fromasm.imprecise.no-opts
+++ b/test/debugInfo.fromasm.imprecise.no-opts
@@ -11,15 +11,15 @@
  (export "fib" (func $fib))
  (export "switch_reach" (func $switch_reach))
  (func $add (param $x i32) (param $y i32) (result i32)
-  ;; tests/hello_world.c:5
+  ;;@ tests/hello_world.c:5:0
   (set_local $x
    (get_local $x)
   )
-  ;; tests/hello_world.c:6
+  ;;@ tests/hello_world.c:6:0
   (set_local $y
    (get_local $y)
   )
-  ;; tests/other_file.cpp:314159
+  ;;@ tests/other_file.cpp:314159:0
   (set_local $x
    (get_local $y)
   )
@@ -31,14 +31,14 @@
   )
  )
  (func $ret (param $x i32) (result i32)
-  ;; return.cpp:50
+  ;;@ return.cpp:50:0
   (set_local $x
    (i32.shl
     (get_local $x)
     (i32.const 1)
    )
   )
-  ;; return.cpp:100
+  ;;@ return.cpp:100:0
   (return
    (i32.add
     (get_local $x)
@@ -47,21 +47,21 @@
   )
  )
  (func $opts (param $x i32) (param $y i32) (result i32)
-  ;; even-opted.cpp:1
+  ;;@ even-opted.cpp:1:0
   (set_local $x
    (i32.add
     (get_local $x)
     (get_local $y)
    )
   )
-  ;; even-opted.cpp:2
+  ;;@ even-opted.cpp:2:0
   (set_local $y
    (i32.shr_s
     (get_local $y)
     (get_local $x)
    )
   )
-  ;; even-opted.cpp:3
+  ;;@ even-opted.cpp:3:0
   (set_local $x
    (i32.rem_s
     (get_local $x)
@@ -90,7 +90,7 @@
   (set_local $sp
    (get_global $STACKTOP)
   )
-  ;; fib.c:3
+  ;;@ fib.c:3:0
   (set_local $$1
    (i32.gt_s
     (get_local $$0)
@@ -114,7 +114,7 @@
     (set_local $$$0$lcssa
      (i32.const 1)
     )
-    ;; fib.c:8
+    ;;@ fib.c:8:0
     (return
      (get_local $$$0$lcssa)
     )
@@ -122,21 +122,20 @@
   )
   (loop $while-in
    (block $while-out
-    ;; fib.c:4
+    ;;@ fib.c:4:0
     (set_local $$2
      (i32.add
       (get_local $$$019)
       (get_local $$$01518)
      )
     )
-    ;; fib.c:3
+    ;;@ fib.c:3:0
     (set_local $$3
      (i32.add
       (get_local $$$01617)
       (i32.const 1)
      )
     )
-    ;; fib.c:3
     (set_local $$exitcond
      (i32.eq
       (get_local $$3)
@@ -169,7 +168,7 @@
     (br $while-in)
    )
   )
-  ;; fib.c:8
+  ;;@ fib.c:8:0
   (return
    (get_local $$$0$lcssa)
   )
@@ -266,7 +265,7 @@
     (get_local $$p)
    )
   )
-  ;; /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950
+  ;;@ /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
   (return
    (get_local $$rc$0)
   )
diff --git a/test/debugInfo.fromasm.imprecise.no-opts.txtmap b/test/debugInfo.fromasm.imprecise.no-opts.txtmap
index 00a07f11cd0..25ae6055e50 100644
--- a/test/debugInfo.fromasm.imprecise.no-opts.txtmap
+++ b/test/debugInfo.fromasm.imprecise.no-opts.txtmap
@@ -1,8 +1,14 @@
-163:tests/hello_world.c:5
-167:tests/hello_world.c:6
-171:tests/other_file.cpp:314159
-193:return.cpp:50
-200:return.cpp:100
-219:even-opted.cpp:1
-226:even-opted.cpp:2
-233:even-opted.cpp:3
+198:tests/hello_world.c:5:0
+202:tests/hello_world.c:6:0
+206:tests/other_file.cpp:314159:0
+228:return.cpp:50:0
+235:return.cpp:100:0
+253:even-opted.cpp:1:0
+260:even-opted.cpp:2:0
+267:even-opted.cpp:3:0
+298:fib.c:3:0
+326:fib.c:8:0
+334:fib.c:4:0
+341:fib.c:3:0
+387:fib.c:8:0
+533:/tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
diff --git a/test/debugInfo.fromasm.imprecise.txtmap b/test/debugInfo.fromasm.imprecise.txtmap
index c9f177cc8be..89e0f75c13a 100644
--- a/test/debugInfo.fromasm.imprecise.txtmap
+++ b/test/debugInfo.fromasm.imprecise.txtmap
@@ -1 +1,12 @@
-190:even-opted.cpp:2
+184:tests/other_file.cpp:314159:0
+198:return.cpp:50:0
+205:return.cpp:100:0
+220:even-opted.cpp:1:0
+227:even-opted.cpp:2:0
+234:even-opted.cpp:3:0
+254:fib.c:3:0
+278:fib.c:8:0
+284:fib.c:4:0
+291:fib.c:3:0
+317:fib.c:8:0
+414:/tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
diff --git a/test/debugInfo.fromasm.no-opts b/test/debugInfo.fromasm.no-opts
index 9e3050695ed..054226a3a3c 100644
--- a/test/debugInfo.fromasm.no-opts
+++ b/test/debugInfo.fromasm.no-opts
@@ -11,15 +11,15 @@
  (export "fib" (func $fib))
  (export "switch_reach" (func $switch_reach))
  (func $add (param $x i32) (param $y i32) (result i32)
-  ;; tests/hello_world.c:5
+  ;;@ tests/hello_world.c:5:0
   (set_local $x
    (get_local $x)
   )
-  ;; tests/hello_world.c:6
+  ;;@ tests/hello_world.c:6:0
   (set_local $y
    (get_local $y)
   )
-  ;; tests/other_file.cpp:314159
+  ;;@ tests/other_file.cpp:314159:0
   (set_local $x
    (get_local $y)
   )
@@ -31,14 +31,14 @@
   )
  )
  (func $ret (param $x i32) (result i32)
-  ;; return.cpp:50
+  ;;@ return.cpp:50:0
   (set_local $x
    (i32.shl
     (get_local $x)
     (i32.const 1)
    )
   )
-  ;; return.cpp:100
+  ;;@ return.cpp:100:0
   (return
    (i32.add
     (get_local $x)
@@ -59,21 +59,21 @@
   )
  )
  (func $opts (param $x i32) (param $y i32) (result i32)
-  ;; even-opted.cpp:1
+  ;;@ even-opted.cpp:1:0
   (set_local $x
    (i32.add
     (get_local $x)
     (get_local $y)
    )
   )
-  ;; even-opted.cpp:2
+  ;;@ even-opted.cpp:2:0
   (set_local $y
    (i32.shr_s
     (get_local $y)
     (get_local $x)
    )
   )
-  ;; even-opted.cpp:3
+  ;;@ even-opted.cpp:3:0
   (set_local $x
    (call $i32s-rem
     (get_local $x)
@@ -102,7 +102,7 @@
   (set_local $sp
    (get_global $STACKTOP)
   )
-  ;; fib.c:3
+  ;;@ fib.c:3:0
   (set_local $$1
    (i32.gt_s
     (get_local $$0)
@@ -126,7 +126,7 @@
     (set_local $$$0$lcssa
      (i32.const 1)
     )
-    ;; fib.c:8
+    ;;@ fib.c:8:0
     (return
      (get_local $$$0$lcssa)
     )
@@ -134,21 +134,20 @@
   )
   (loop $while-in
    (block $while-out
-    ;; fib.c:4
+    ;;@ fib.c:4:0
     (set_local $$2
      (i32.add
       (get_local $$$019)
       (get_local $$$01518)
      )
     )
-    ;; fib.c:3
+    ;;@ fib.c:3:0
     (set_local $$3
      (i32.add
       (get_local $$$01617)
       (i32.const 1)
      )
     )
-    ;; fib.c:3
     (set_local $$exitcond
      (i32.eq
       (get_local $$3)
@@ -181,7 +180,7 @@
     (br $while-in)
    )
   )
-  ;; fib.c:8
+  ;;@ fib.c:8:0
   (return
    (get_local $$$0$lcssa)
   )
@@ -278,7 +277,7 @@
     (get_local $$p)
    )
   )
-  ;; /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950
+  ;;@ /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
   (return
    (get_local $$rc$0)
   )
diff --git a/test/debugInfo.fromasm.no-opts.txtmap b/test/debugInfo.fromasm.no-opts.txtmap
index eec2e7bd354..f7b8c313154 100644
--- a/test/debugInfo.fromasm.no-opts.txtmap
+++ b/test/debugInfo.fromasm.no-opts.txtmap
@@ -1,8 +1,14 @@
-164:tests/hello_world.c:5
-168:tests/hello_world.c:6
-172:tests/other_file.cpp:314159
-194:return.cpp:50
-201:return.cpp:100
-241:even-opted.cpp:1
-248:even-opted.cpp:2
-255:even-opted.cpp:3
+199:tests/hello_world.c:5:0
+203:tests/hello_world.c:6:0
+207:tests/other_file.cpp:314159:0
+229:return.cpp:50:0
+236:return.cpp:100:0
+275:even-opted.cpp:1:0
+282:even-opted.cpp:2:0
+289:even-opted.cpp:3:0
+321:fib.c:3:0
+349:fib.c:8:0
+357:fib.c:4:0
+364:fib.c:3:0
+410:fib.c:8:0
+556:/tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
diff --git a/test/debugInfo.fromasm.txtmap b/test/debugInfo.fromasm.txtmap
index bb25b4d8d30..5ab814a0d4a 100644
--- a/test/debugInfo.fromasm.txtmap
+++ b/test/debugInfo.fromasm.txtmap
@@ -1,2 +1,12 @@
-211:even-opted.cpp:2
-223:even-opted.cpp:3
+185:tests/other_file.cpp:314159:0
+199:return.cpp:50:0
+206:return.cpp:100:0
+241:even-opted.cpp:1:0
+248:even-opted.cpp:2:0
+255:even-opted.cpp:3:0
+276:fib.c:3:0
+300:fib.c:8:0
+306:fib.c:4:0
+313:fib.c:3:0
+339:fib.c:8:0
+436:/tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
diff --git a/test/dot_s/debug.wast b/test/dot_s/debug.wast
index aa4f34d9e71..0cc0ae20c9e 100644
--- a/test/dot_s/debug.wast
+++ b/test/dot_s/debug.wast
@@ -18,18 +18,21 @@
   )
   (block $label$0
    (loop $label$1
+    ;;@ fib.c:3:17
     (set_local $2
      (i32.add
       (get_local $2)
       (i32.const 1)
      )
     )
+    ;;@ fib.c:3:3
     (br_if $label$0
      (i32.ge_s
       (get_local $2)
       (get_local $0)
      )
     )
+    ;;@ fib.c:4:11
     (set_local $1
      (i32.add
       (get_local $4)
@@ -45,6 +48,7 @@
     (br $label$1)
    )
   )
+  ;;@ fib.c:6:3
   (return
    (get_local $4)
   )