[debug] discard source map step if file equal -1

fix https://github.com/ethereum/remix-ide/issues/2648

remix-lib/src/sourceMappingDecoder.js

@@ -188,8 +188,23 @@ function nodesAtPosition (astNodeType, position, ast) {
   return found
 }
 
+/**
+ * starts with the given @arg index and move backward until it can find all the values for start, length, file, jump
+ * if `file === -1` then the value of the sourcemap should be taken from the previous step,
+ * because some steps are internal subroutine for the compiler and doesn't link to any high level code.
+ *
+ * Solidity source maps format is
+ *  - start:length:file:jump
+ *  - jump can be 'i', 'o' or '-' (jump 'in' or 'out' of a function)
+ *  - if no value is specified ( e.g "5:2" - no mention of 'file' and 'jump' ), actual values are the one of the step before
+ *  - if the file (3rd value) has -1, the source maps should be discarded
+ *
+ *  @param Int index - index in the bytecode to decode source mapping from
+ *  @param Array mapping - source maps returned by the compiler. e.g 121:3741:0:-:0;;;;8:9:-1;5:2;;;30:1;27;20:12;5:2;121:3741:0;;;;;;;
+ *  @return Object { start, length, file, jump }
+ */
 function atIndex (index, mapping) {
-  const ret = {}
+  let ret = {}
   const map = mapping.split(';')
   if (index >= map.length) {
     index = map.length - 1
@@ -200,6 +215,10 @@ function atIndex (index, mapping) {
       continue
     }
     current = current.split(':')
+    if (current[2] === '-1') { // if the current step has -1 for the file attribute, we discard it
+      if (ret.file === undefined) ret = {} // if the file was not already set by a previous (meaning it is -1), we discard the whole step
+      continue
+    }
     if (ret.start === undefined && current[0] && current[0] !== '-1' && current[0].length) {
       ret.start = parseInt(current[0])
     }

remix-lib/test/resources/sourceMapping.js

@@ -17,6 +17,74 @@ sourceRuntimeMapping.source = `contract test {
     }
 }`
 
+sourceRuntimeMapping.ballotSourceMap = '33:1970:0:-;;;;8:9:-1;5:2;;;30:1;27;20:12;5:2;33:1970:0;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;712:577;;;;;;13:2:-1;8:3;5:11;2:2;;;29:1;26;19:12;2:2;712:577:0;;;;;;;;;;;;;;;;;;;:::i;:::-;;1641:360;;;:::i;:::-;;;;;;;;;;;;;;;;;;;;;;;495:164;;;;;;13:2:-1;8:3;5:11;2:2;;;29:1;26;19:12;2:2;495:164:0;;;;;;;;;;;;;;;;;;;:::i;:::-;;1349:286;;;;;;13:2:-1;8:3;5:11;2:2;;;29:1;26;19:12;2:2;1349:286:0;;;;;;;;;;;;;;;;;;;:::i;:::-;;712:577;759:20;782:6;:18;789:10;782:18;;;;;;;;;;;;;;;759:41;;835:6;:12;;;;;;;;;;;;831:25;;;849:7;;;831:25;865:115;903:1;872:33;;:6;:10;879:2;872:10;;;;;;;;;;;;;;;:19;;;;;;;;;;;;:33;;;;:70;;;;;932:10;909:33;;:6;:10;916:2;909:10;;;;;;;;;;;;;;;:19;;;;;;;;;;;;:33;;;;872:70;865:115;;;961:6;:10;968:2;961:10;;;;;;;;;;;;;;;:19;;;;;;;;;;;;956:24;;865:115;;;1000:10;994:16;;:2;:16;;;990:29;;;1012:7;;;990:29;1043:4;1028:6;:12;;;:19;;;;;;;;;;;;;;;;;;1075:2;1057:6;:15;;;:20;;;;;;;;;;;;;;;;;;1087:24;1114:6;:10;1121:2;1114:10;;;;;;;;;;;;;;;1087:37;;1138:10;:16;;;;;;;;;;;;1134:148;;;1208:6;:13;;;1168:9;1178:10;:15;;;;;;;;;;;;1168:26;;;;;;;;;;;;;;;;;:36;;;:53;;;;;;;;;;;1134:148;;;1269:6;:13;;;1248:10;:17;;;:34;;;;;;;;;;;1134:148;712:577;;;;:::o;1641:360::-;1689:22;1723:24;1750:1;1723:28;;1766:10;1779:1;1766:14;;1761:234;1789:9;:16;;;;1782:4;:23;;;1761:234;;;1859:16;1831:9;1841:4;1831:15;;;;;;;;;;;;;;;;;:25;;;:44;1827:168;;;1914:9;1924:4;1914:15;;;;;;;;;;;;;;;;;:25;;;1895:44;;1976:4;1957:23;;1827:168;1807:6;;;;;;;1761:234;;;;1641:360;;:::o;495:164::-;572:11;;;;;;;;;;;558:25;;:10;:25;;;;:50;;;;587:6;:15;594:7;587:15;;;;;;;;;;;;;;;:21;;;;;;;;;;;;558:50;554:63;;;610:7;;554:63;651:1;626:6;:15;633:7;626:15;;;;;;;;;;;;;;;:22;;:26;;;;495:164;;:::o;1349:286::-;1398:20;1421:6;:18;1428:10;1421:18;;;;;;;;;;;;;;;1398:41;;1453:6;:12;;;;;;;;;;;;:46;;;;1483:9;:16;;;;1469:10;:30;;;;1453:46;1449:59;;;1501:7;;;1449:59;1532:4;1517:6;:12;;;:19;;;;;;;;;;;;;;;;;;1560:10;1546:6;:11;;;:24;;;;;;;;;;;;;;;;;;1615:6;:13;;;1580:9;1590:10;1580:21;;;;;;;;;;;;;;;;;:31;;;:48;;;;;;;;;;;1349:286;;;:::o'
+sourceRuntimeMapping.ballotSource = `
+pragma solidity >=0.4.22 <0.6.0;
+contract Ballot {
+
+    struct Voter {
+        uint weight;
+        bool voted;
+        uint8 vote;
+        address delegate;
+    }
+
+    struct Proposal {
+        uint voteCount;
+    }
+
+    address chairperson;
+    mapping(address => Voter) voters;
+    Proposal[] proposals;
+    
+    function () external {
+        
+    }
+
+   
+    /// Give $(toVoter) the right to vote on this ballot.
+    /// May only be called by $(chairperson).
+    /// @notice something 2
+    function giveRightToVote(address toVoter) public {
+        if (msg.sender != chairperson || voters[toVoter].voted) return;
+        voters[toVoter].weight = 1;
+    }
+
+    /// Delegate your vote to the voter $(to).
+    function delegate(address to) public {
+        Voter storage sender = voters[msg.sender]; // assigns reference
+        if (sender.voted) return;
+        while (voters[to].delegate != address(0) && voters[to].delegate != msg.sender)
+            to = voters[to].delegate;
+        if (to == msg.sender) return;
+        sender.voted = true;
+        sender.delegate = to;
+        Voter storage delegateTo = voters[to];
+        if (delegateTo.voted)
+            proposals[delegateTo.vote].voteCount += sender.weight;
+        else
+            delegateTo.weight += sender.weight;
+    }
+
+    /// Give a single vote to proposal $(toProposal).
+    function vote(uint8 toProposal) public {
+        Voter storage sender = voters[msg.sender];
+        if (sender.voted || toProposal >= proposals.length) return;
+        sender.voted = true;
+        sender.vote = toProposal;
+        proposals[toProposal].voteCount += sender.weight;
+    }
+
+    function winningProposal() public view returns (uint8 _winningProposal) {
+        uint256 winningVoteCount = 0;
+        for (uint8 prop = 0; prop < proposals.length; prop++)
+            if (proposals[prop].voteCount > winningVoteCount) {
+                winningVoteCount = proposals[prop].voteCount;
+                _winningProposal = prop;
+            }
+    }
+}
+`
 if (typeof (module) !== 'undefined' && typeof (module.exports) !== 'undefined') {
   module.exports = sourceRuntimeMapping
 }

remix-lib/test/sourceMappingDecoder.js

@@ -22,7 +22,7 @@ tape('SourceMappingDecoder', function (t) {
 
   const testSourceMapping = {}
   t.test('sourceMappingDecoder', function (st) {
-    st.plan(28)
+    st.plan(32)
     const sourceMappingDecoder = new SourceMappingDecoder()
     console.log('test decompressAll')
     let result = sourceMappingDecoder.decompressAll(sourceMapping.mapping)
@@ -73,6 +73,14 @@ tape('SourceMappingDecoder', function (t) {
     st.equal(result.file, 4)
     st.equal(result.jump, '-')
     testSourceMapping[85] = result
+
+    // ballot - function deletegate(address)
+    const delegateSrcMap = sourceMappingDecoder.atIndex(64, sourceMapping.ballotSourceMap)
+    console.log(delegateSrcMap)
+    st.equal(delegateSrcMap.start, 712)
+    st.equal(delegateSrcMap.length, 577)
+    st.equal(delegateSrcMap.file, 0)
+    st.equal(delegateSrcMap.jump, '-')
   })
 
   t.test('sourceMappingLineColumnConverter', function (st) {