[lld] r352928 - [COFF] Fix crashes when writing a PDB after adding thunks.

[Martin Storsjo via llvm-commits]

Author: mstorsjo
Date: Fri Feb  1 14:08:03 2019
New Revision: 352928

URL: http://llvm.org/viewvc/llvm-project?rev=352928&view=rev
Log:
[COFF] Fix crashes when writing a PDB after adding thunks.

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.

Differential Revision: https://reviews.llvm.org/D57574

Added:
    lld/trunk/test/COFF/arm-thumb-thunks-pdb.s
Modified:
    lld/trunk/COFF/Writer.cpp

Modified: lld/trunk/COFF/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Writer.cpp?rev=352928&r1=352927&r2=352928&view=diff
==============================================================================
--- lld/trunk/COFF/Writer.cpp (original)
+++ lld/trunk/COFF/Writer.cpp Fri Feb  1 14:08:03 2019
@@ -373,14 +373,14 @@ getThunk(DenseMap<uint64_t, Defined *> &
 // 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 @@ static bool createThunks(std::vector<Chu
         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 @@ void Writer::finalizeAddresses() {
     // 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);

Added: lld/trunk/test/COFF/arm-thumb-thunks-pdb.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/COFF/arm-thumb-thunks-pdb.s?rev=352928&view=auto
==============================================================================
--- lld/trunk/test/COFF/arm-thumb-thunks-pdb.s (added)
+++ lld/trunk/test/COFF/arm-thumb-thunks-pdb.s Fri Feb  1 14:08:03 2019
@@ -0,0 +1,18 @@
+// 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