forked from OSchip/llvm-project
6b01b46538
The builtin function
u32 btf_type_id = __builtin_btf_type_id(param, 0)
can help preserve type info for the following use case:
extern void foo(..., void *data, int size);
int test(...) {
struct t { int a; int b; int c; } d;
d.a = ...; d.b = ...; d.c = ...;
foo(..., &d, sizeof(d));
}
The function "foo" in the above only see raw data and does not
know what type of the data is. In certain cases, e.g., logging,
the additional type information will help pretty print.
This patch handles the builtin in BPF backend. It includes
an IR pass to translate the IR intrinsic to a load of
a global variable which carries the metadata, and an MI
pass to remove the intermediate load of the global variable.
Finally, in AsmPrinter pass, proper instruction are generated.
In the above example, the second argument for __builtin_btf_type_id()
is 0, which means a relocation for local adjustment,
i.e., w.r.t. bpf program BTF change, will be generated.
The value 1 for the second argument means
a relocation for remote adjustment, e.g., against vmlinux.
Differential Revision: https://reviews.llvm.org/D74572
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| llvm.spec.in | ||
README.txt
The LLVM Compiler Infrastructure ================================ This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments. LLVM is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt. Please see the documentation provided in docs/ for further assistance with LLVM, and in particular docs/GettingStarted.rst for getting started with LLVM and docs/README.txt for an overview of LLVM's documentation setup. If you are writing a package for LLVM, see docs/Packaging.rst for our suggestions.