Handle debug info without a filename in asm2wasm (#1249)

* support debug info without a filename in asm2wasm input (which can happen if llvm doesn't know the file, only the line)

Author: kripken

src/asm2wasm.h

@@ -262,20 +262,43 @@ struct Asm2WasmPreProcessor {
       char* out = copy;
       std::string DEBUGINFO_INTRINSIC = EMSCRIPTEN_DEBUGINFO.str;
       auto DEBUGINFO_INTRINSIC_SIZE = DEBUGINFO_INTRINSIC.size();
+      const char* UNKNOWN_FILE = "(unknown)";
       bool seenUseAsm = false;
       while (input[0]) {
         if (out + ADD_FACTOR >= end) {
           Fatal() << "error in handling debug info";
         }
         if (startsWith(input, "//@line")) {
           char* linePos = input + 8;
-          char* lineEnd = strchr(input + 8, ' ');
-          char* filePos = strchr(lineEnd, '"') + 1;
-          char* fileEnd = strchr(filePos, '"');
-          input = fileEnd + 1;
+          char* lineEnd = strpbrk(input + 8, " \n");
+          if (!lineEnd) {
+            // comment goes to end of input
+            break;
+          }
+          input = lineEnd + 1;
+          std::string file;
+          if (*lineEnd == ' ') {
+            // we have a file
+            char* filePos = strpbrk(input, "\"\n");
+            if (!filePos) {
+              // goes to end of input
+              break;
+            }
+            if (*filePos == '"') {
+              char* fileEnd = strpbrk(filePos + 1, "\"\n");
+              input = fileEnd + 1;
+              *fileEnd = 0;
+              file = filePos + 1;
+            } else {
+              file = UNKNOWN_FILE;
+              input = filePos + 1;
+            }
+          } else {
+            // no file, we found \n
+            file = UNKNOWN_FILE;
+          }
           *lineEnd = 0;
-          *fileEnd = 0;
-          std::string line = linePos, file = filePos;
+          std::string line = linePos;
           auto iter = debugInfoFileIndices.find(file);
           if (iter == debugInfoFileIndices.end()) {
             Index index = debugInfoFileNames.size();

test/debugInfo.asm.js

@@ -81,6 +81,9 @@ function () {
    switch_reach($p) | 0;
    return ($rc$0|0); //@line 59950 "/tmp/emscripten_test_binaryen2_28hnAe/src.c"
   }
-  return { add: add, ret: ret, opts: opts, fib: fib, switch_reach: switch_reach };
+  function nofile() {
+    nofile(); //@line 1337
+  }
+  return { add: add, ret: ret, opts: opts, fib: fib, switch_reach: switch_reach, nofile: nofile };
 }
 

test/debugInfo.fromasm

@@ -10,6 +10,7 @@
  (export "opts" (func $opts))
  (export "fib" (func $fib))
  (export "switch_reach" (func $switch_reach))
+ (export "nofile" (func $nofile))
  (func $add (; 0 ;) (param $0 i32) (param $1 i32) (result i32)
   ;;@ tests/other_file.cpp:314159:0
   (i32.add
@@ -188,4 +189,8 @@
   ;;@ /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
   (get_local $1)
  )
+ (func $nofile (; 5 ;)
+  ;;@ (unknown):1337:0
+  (call $nofile)
+ )
 )

test/debugInfo.fromasm.clamp

@@ -10,6 +10,7 @@
  (export "opts" (func $opts))
  (export "fib" (func $fib))
  (export "switch_reach" (func $switch_reach))
+ (export "nofile" (func $nofile))
  (func $add (; 0 ;) (param $0 i32) (param $1 i32) (result i32)
   ;;@ tests/other_file.cpp:314159:0
   (i32.add
@@ -188,4 +189,8 @@
   ;;@ /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
   (get_local $1)
  )
+ (func $nofile (; 5 ;)
+  ;;@ (unknown):1337:0
+  (call $nofile)
+ )
 )

test/debugInfo.fromasm.clamp.map

@@ -10,6 +10,7 @@
  (export "opts" (func $opts))
  (export "fib" (func $fib))
  (export "switch_reach" (func $switch_reach))
+ (export "nofile" (func $nofile))
  (func $add (; 0 ;) (param $x i32) (param $y i32) (result i32)
   ;;@ tests/hello_world.c:5:0
   (set_local $x
@@ -282,4 +283,8 @@
    (get_local $$rc$0)
   )
  )
+ (func $nofile (; 6 ;)
+  ;;@ (unknown):1337:0
+  (call $nofile)
+ )
 )

test/debugInfo.fromasm.clamp.no-opts

@@ -9,6 +9,7 @@
  (export "opts" (func $opts))
  (export "fib" (func $fib))
  (export "switch_reach" (func $switch_reach))
+ (export "nofile" (func $nofile))
  (func $add (; 0 ;) (param $0 i32) (param $1 i32) (result i32)
   ;;@ tests/other_file.cpp:314159:0
   (i32.add
@@ -180,4 +181,8 @@
   ;;@ /tmp/emscripten_test_binaryen2_28hnAe/src.c:59950:0
   (get_local $1)
  )
+ (func $nofile (; 5 ;)
+  ;;@ (unknown):1337:0
+  (call $nofile)
+ )
 )

test/debugInfo.fromasm.clamp.no-opts.map

@@ -10,6 +10,7 @@
  (export "opts" (func $opts))
  (export "fib" (func $fib))
  (export "switch_reach" (func $switch_reach))
+ (export "nofile" (func $nofile))
  (func $add (; 0 ;) (param $x i32) (param $y i32) (result i32)
   ;;@ tests/hello_world.c:5:0
   (set_local $x
@@ -270,4 +271,8 @@
    (get_local $$rc$0)
   )
  )
+ (func $nofile (; 5 ;)
+  ;;@ (unknown):1337:0
+  (call $nofile)
+ )
 )