[all-commits] [llvm/llvm-project] 88d3c1: [lldb][ClangExpression] Add asm() label to all Fun...
Michael137 via All-commits
all-commits at lists.llvm.org
Wed Aug 17 01:03:12 PDT 2022
Author: Michael Buch <michaelbuch12 at gmail.com>
Date: 2022-08-17 (Wed, 17 Aug 2022)
[lldb][ClangExpression] Add asm() label to all FunctionDecls we create from DWARF
When resolving symbols during IR execution, lldb makes a last effort attempt
to resolve external symbols from object files by approximate name matching.
It currently uses `CPlusPlusNameParser` to parse the demangled function name
and arguments for the unresolved symbol and its candidates. However, this
hand-rolled C++ parser doesn’t support ABI tags which, depending on the demangler,
get demangled into `[abi:tag]`. This lack of parsing support causes lldb to never
consider a candidate mangled function name that has ABI tags.
The issue reproduces by calling an ABI-tagged template function from the
expression evaluator. This is particularly problematic with the recent
addition of ABI tags to numerous libcxx APIs.
The issue stems from the fact that `clang::CodeGen` emits function
function calls using the mangled name inferred from the `FunctionDecl`
LLDB constructs from DWARF. Debug info often lacks information for
us to construct a perfect FunctionDecl resulting in subtle mangled
This patch side-steps the problem of inaccurate `FunctionDecl`s by
attaching an `asm()` label to each `FunctionDecl` LLDB creates from DWARF.
`clang::CodeGen` consults this label to get the mangled name as one of
the first courses of action when emitting a function call.
LLDB already does this for C++ member functions as of
* Added API tests
Differential Revision: https://reviews.llvm.org/D131974
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