[PATCH] D88369: [lld][WebAssembly] Fix segfault in map file support

[Thomas Lively via Phabricator via llvm-commits]

tlively created this revision.
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The code previously assumed that `getChunk` would return a non-null pointer for
every symbol, but in fact it only returns non-null pointers for DefinedFunction
and DefinedData symbols. This patch fixes the segfault by checking whether
`getChunk` returns a null for each symbol and skipping the mapping output for
any symbols for which it does.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D88369

Files:
  lld/wasm/MapFile.cpp


Index: lld/wasm/MapFile.cpp
===================================================================
--- lld/wasm/MapFile.cpp
+++ lld/wasm/MapFile.cpp
@@ -76,8 +76,11 @@
   std::vector<std::string> str(syms.size());
   parallelForEachN(0, syms.size(), [&](size_t i) {
     raw_string_ostream os(str[i]);
-    auto &chunk = *syms[i]->getChunk();
-    uint64_t fileOffset = chunk.outputSec->getOffset() + chunk.outputOffset;
+    auto *chunk = syms[i]->getChunk();
+    // TODO: Handle symbol types besides DefinedFunction and DefinedData
+    if (!chunk)
+      return;
+    uint64_t fileOffset = chunk->outputSec->getOffset() + chunk->outputOffset;
     uint64_t vma = -1;
     uint64_t size = 0;
     if (auto *DD = dyn_cast<DefinedData>(syms[i])) {


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