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| author | Chandler Carruth <chandlerc@gmail.com> | 2011-11-24 11:23:15 +0000 |
|---|---|---|
| committer | Chandler Carruth <chandlerc@gmail.com> | 2011-11-24 11:23:15 +0000 |
| commit | 4aae4f90071f64854ec771496bd164149b0a1352 (patch) | |
| tree | a79d236ff20fd5ee89e5e0081625f5780e9035af /lib/CodeGen/MachineBlockPlacement.cpp | |
| parent | a2deea1dcf8363f46bda8935283c5c701b5a278d (diff) | |
| download | llvm-4aae4f90071f64854ec771496bd164149b0a1352.tar.gz llvm-4aae4f90071f64854ec771496bd164149b0a1352.tar.bz2 llvm-4aae4f90071f64854ec771496bd164149b0a1352.tar.xz | |
Fix a silly use-after-free issue. A much earlier version of this code
need lots of fanciness around retaining a reference to a Chain's slot in
the BlockToChain map, but that's all gone now. We can just go directly
to allocating the new chain (which will update the mapping for us) and
using it.
Somewhat gross mechanically generated test case replicates the issue
Duncan spotted when actually testing this out.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145120 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/MachineBlockPlacement.cpp')
| -rw-r--r-- | lib/CodeGen/MachineBlockPlacement.cpp | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/lib/CodeGen/MachineBlockPlacement.cpp b/lib/CodeGen/MachineBlockPlacement.cpp index 870e24884a..55d804b31e 100644 --- a/lib/CodeGen/MachineBlockPlacement.cpp +++ b/lib/CodeGen/MachineBlockPlacement.cpp @@ -640,8 +640,8 @@ void MachineBlockPlacement::buildCFGChains(MachineFunction &F) { SmallVector<MachineOperand, 4> Cond; // For AnalyzeBranch. for (MachineFunction::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI) { MachineBasicBlock *BB = FI; - BlockChain *&Chain = BlockToChain[BB]; - Chain = new (ChainAllocator.Allocate()) BlockChain(BlockToChain, BB); + BlockChain *Chain + = new (ChainAllocator.Allocate()) BlockChain(BlockToChain, BB); // Also, merge any blocks which we cannot reason about and must preserve // the exact fallthrough behavior for. for (;;) { |