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Basic LLVM module pass causes segfault #31067

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frewsxcv opened this issue Jan 21, 2016 · 1 comment
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Basic LLVM module pass causes segfault #31067

frewsxcv opened this issue Jan 21, 2016 · 1 comment
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A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. A-plugins Area: compiler plugins, doc.rust-lang.org/nightly/unstable-book/language-features/plugin.html

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@frewsxcv
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Started occurring after f9d4149 merged

Repo exemplifying segfault

Relevant file in repo

To exemplify:

  1. set LLVM_CONFIG environment variable to llvm-config path
  2. cargo build --verbose

Result of stepping through the code with LLDB

Another example of a module pass exemplifying a crash:

bool InstrumentationPass::runOnModule(Module &M) {
  LLVMContext &C = M.getContext();
  IntegerType *Int8Ty  = IntegerType::getInt8Ty(C);
  llvm::Type *i = PointerType::get(Int8Ty, 0);  // segfault happens here
  return true;
}

This is preventing afl.rs from upgrading compatibility with any Rust version >1.2:
@frewsxcv frewsxcv mentioned this issue Jan 21, 2016
Closed
@nagisa nagisa added A-plugins Area: compiler plugins, doc.rust-lang.org/nightly/unstable-book/language-features/plugin.html A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. labels Jan 21, 2016
@frewsxcv frewsxcv mentioned this issue Jan 25, 2016
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@frewsxcv
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Opened a PR that fixes this #31176

frewsxcv added a commit to frewsxcv/rust that referenced this issue Jan 25, 2016
@frewsxcv
Register LLVM passes with the correct LLVM pass manager.
d942621 
LLVM was upgraded to a new version in this commit:

rust-lang@f9d4149

which was part of this pull request:

rust-lang#26025

Consider the following two lines from that commit:

rust-lang@f9d4149#diff-a3b24dbe2ea7c1981f9ac79f9745f40aL462

rust-lang@f9d4149#diff-a3b24dbe2ea7c1981f9ac79f9745f40aL469

The purpose of these lines is to register LLVM passes. Prior to the that
commit, the passes being handled were assumed to be ModulePasses (a
specific type of LLVM pass) since they were being added to a ModulePass
manager. After that commit, both lines were refactored (presumably in an
attempt to DRY out the code), but the ModulePasses were changed to be
registered to a FunctionPass manager. This change resulted in
ModulePasses being run, but a Function object was being passed as a
parameter to the pass instead of a Module, which resulted in
segmentation faults.

In this commit, I changed relevant sections of the code to check the
type of the passes being added and register them to the appropriate pass
manager.

Closes rust-lang#31067
bors added a commit that referenced this issue Jan 25, 2016
@bors
Auto merge of #31176 - frewsxcv:incorrect-pass-kind, r=dotdash
c22cb53 
Register LLVM passes with the correct LLVM pass manager.

LLVM was upgraded to a new version in this commit:

f9d4149

which was part of this pull request:

#26025

Consider the following two lines from that commit:

f9d4149#diff-a3b24dbe2ea7c1981f9ac79f9745f40aL462

f9d4149#diff-a3b24dbe2ea7c1981f9ac79f9745f40aL469

The purpose of these lines is to register LLVM passes. Prior to the that
commit, the passes being handled were assumed to be ModulePasses (a
specific type of LLVM pass) since they were being added to a ModulePass
manager. After that commit, both lines were refactored (presumably in an
attempt to DRY out the code), but the ModulePasses were changed to be
registered to a FunctionPass manager. This change resulted in
ModulePasses being run, but a Function object was being passed as a
parameter to the pass instead of a Module, which resulted in
segmentation faults.

In this commit, I changed relevant sections of the code to check the
type of the passes being added and register them to the appropriate pass
manager.

Closes #31067
@frewsxcv frewsxcv mentioned this issue Jan 25, 2016
Closed
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A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. A-plugins Area: compiler plugins, doc.rust-lang.org/nightly/unstable-book/language-features/plugin.html
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