Currently (for codeview) lambdas have a string like `<lambda_0>` in
their mangled name, and don't have any display name. This change uses the
`<lambda_0>` as the display name, which helps distinguish between lambdas
in -gline-tables-only, since there are no linkage names there.
It also changes how we display lambda names; previously we used
`<unnamed-tag>`; now it will show `<lambda_0>`.
I added a function to the mangling context code to create this string;
for Itanium it just returns an empty string.
Bug: https://bugs.llvm.org/show_bug.cgi?id=48432
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D95187
This change will help Visual Studio resolve forward references to C++ lambda
routines used by captured variables.
Differential Revision: https://reviews.llvm.org/D45438
llvm-svn: 332975