[PATCH] D57574: [LLD] [COFF] Fix crashes when writing a PDB after adding thunks.

[Martin Storsjö via Phabricator via llvm-commits]

mstorsjo created this revision.
mstorsjo added reviewers: ruiu, rnk, dmajor.
Herald added a subscriber: javed.absar.
Herald added a project: LLVM.

When writing a PDB, the OutputSection of all chunks need to be set. The thunks are added directly to OutputSection after the normal machinery that sets it for all other chunks.

This fixes part of PR40467.


Repository:
  rLLD LLVM Linker

https://reviews.llvm.org/D57574

Files:
  COFF/Writer.cpp
  test/COFF/arm-thumb-thunks-pdb.s


Index: test/COFF/arm-thumb-thunks-pdb.s
===================================================================
--- /dev/null
+++ test/COFF/arm-thumb-thunks-pdb.s
@@ -0,0 +1,19 @@
+// REQUIRES: arm
+// RUN: llvm-mc -filetype=obj -triple=thumbv7-windows %s -o %t.obj
+// RUN: lld-link -entry:main -subsystem:console %t.obj -out:%t.exe -debug -pdb:%t.pdb -verbose 2>&1 | FileCheck %s --check-prefix=VERBOSE
+
+// VERBOSE: Added 1 thunks with margin {{.*}} in {{.*}} passes
+
+
+    .syntax unified
+    .globl main
+    .globl func1
+    .text
+main:
+    bne func1
+    bx lr
+    .section .text$a, "xr"
+    .space 0x100000
+    .section .text$b, "xr"
+func1:
+    bx lr
Index: COFF/Writer.cpp
===================================================================
--- COFF/Writer.cpp
+++ COFF/Writer.cpp
@@ -373,14 +373,14 @@
 // After adding thunks, we verify that all relocations are in range (with
 // no extra margin requirements). If this failed, we restart (throwing away
 // the previously created thunks) and retry with a wider margin.
-static bool createThunks(std::vector<Chunk *> &Chunks, int Margin) {
+static bool createThunks(OutputSection *OS, int Margin) {
   bool AddressesChanged = false;
   DenseMap<uint64_t, Defined *> LastThunks;
   size_t ThunksSize = 0;
   // Recheck Chunks.size() each iteration, since we can insert more
   // elements into it.
-  for (size_t I = 0; I != Chunks.size(); ++I) {
-    SectionChunk *SC = dyn_cast_or_null<SectionChunk>(Chunks[I]);
+  for (size_t I = 0; I != OS->Chunks.size(); ++I) {
+    SectionChunk *SC = dyn_cast_or_null<SectionChunk>(OS->Chunks[I]);
     if (!SC)
       continue;
     size_t ThunkInsertionSpot = I + 1;
@@ -417,7 +417,8 @@
         Chunk *ThunkChunk = Thunk->getChunk();
         ThunkChunk->setRVA(
             ThunkInsertionRVA); // Estimate of where it will be located.
-        Chunks.insert(Chunks.begin() + ThunkInsertionSpot, ThunkChunk);
+        ThunkChunk->setOutputSection(OS);
+        OS->Chunks.insert(OS->Chunks.begin() + ThunkInsertionSpot, ThunkChunk);
         ThunkInsertionSpot++;
         ThunksSize += ThunkChunk->getSize();
         ThunkInsertionRVA += ThunkChunk->getSize();
@@ -506,7 +507,7 @@
     // to avoid things going out of range due to the added thunks.
     bool AddressesChanged = false;
     for (OutputSection *Sec : OutputSections)
-      AddressesChanged |= createThunks(Sec->Chunks, Margin);
+      AddressesChanged |= createThunks(Sec, Margin);
     // If the verification above thought we needed thunks, we should have
     // added some.
     assert(AddressesChanged);


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