[PATCH] D60757: Fix a crash bug caused by a nested call of parallelForEach.

[Rui Ueyama via Phabricator via llvm-commits]

ruiu created this revision.
ruiu added reviewers: andrewrk, sbc100.
Herald added a subscriber: aheejin.
Herald added a project: LLVM.

parallelForEach is not reentrant. We use parallelForEach to call
each section's writeTo(), so calling the same function within writeTo()
is not safe.

Fixes https://bugs.llvm.org/show_bug.cgi?id=41508


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D60757

Files:
  lld/wasm/OutputSections.cpp


Index: lld/wasm/OutputSections.cpp
===================================================================
--- lld/wasm/OutputSections.cpp
+++ lld/wasm/OutputSections.cpp
@@ -110,8 +110,8 @@
   memcpy(Buf, CodeSectionHeader.data(), CodeSectionHeader.size());
 
   // Write code section bodies
-  parallelForEach(Functions,
-                  [&](const InputChunk *Chunk) { Chunk->writeTo(Buf); });
+  for (const InputChunk *Chunk : Functions)
+    Chunk->writeTo(Buf);
 }
 
 uint32_t CodeSection::numRelocations() const {
@@ -175,7 +175,7 @@
   // Write data section headers
   memcpy(Buf, DataSectionHeader.data(), DataSectionHeader.size());
 
-  parallelForEach(Segments, [&](const OutputSegment *Segment) {
+  for (const OutputSegment *Segment : Segments) {
     // Write data segment header
     uint8_t *SegStart = Buf + Segment->SectionOffset;
     memcpy(SegStart, Segment->Header.data(), Segment->Header.size());
@@ -183,7 +183,7 @@
     // Write segment data payload
     for (const InputChunk *Chunk : Segment->InputSegments)
       Chunk->writeTo(Buf);
-  });
+  }
 }
 
 uint32_t DataSection::numRelocations() const {
@@ -231,8 +231,8 @@
   Buf += NameData.size();
 
   // Write custom sections payload
-  parallelForEach(InputSections,
-                  [&](const InputSection *Section) { Section->writeTo(Buf); });
+  for (const InputSection *Section : InputSections)
+    Section->writeTo(Buf);
 }
 
 uint32_t CustomSection::numRelocations() const {


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