[PATCH] D120168: [Debuginfo][LSR][NFC] Add support for salvaging variadic dbg.value intrinsics [1/2]

[Chris Jackson via Phabricator via llvm-commits]

chrisjackson added a comment.

In D120168#3363344 <https://reviews.llvm.org/D120168#3363344>, @Orlando wrote:

> The change SGTM but I found a reproducer that causes clang to crash when this patch is applied:
>
>   $ cat reduce.cpp
>   #include <utility>
>   template <typename a> class Vec {
>   public:
>     void push(a);
>   };
>   void d(int argc, char **argv) {
>     Vec<std::pair<char *, unsigned>> e;
>     for (int f = 0;;)
>       for (; f < argc; ++f)
>         e.push(std::make_pair(argv[f], f));
>   }
>   
>   $ clang++  -O2 -g reduce.cpp
>   
>   /home/och/dev/llvm/llvm-project/llvm/lib/CodeGen/AsmPrinter/DebugLocEntry.h:139: llvm::DbgValueLoc::DbgValueLoc(const llvm::DIExpression*, llvm::ArrayRef<llvm::DbgValueLocEntry>, bool): Assertion `Expr && Expr->isValid() && is_contained(Expr->getElements(), dwarf::DW_OP_stack_value)' failed.
>   ...

Oops, looks like when I split my patch into two I failed to restore some critical code. Sometimes LSR itself modifies the number of location ops in a dbg.value. If scev-based salvaging is to attempt recovery it must first restore the dbg.value to a single-op state by removing the DIArglist in the first argument. I will restore the code.


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