[clang] 1e06b16 - [clang][docs] Document additional bits of libc that -ffreestanding envs must provide

[Jon Roelofs via cfe-commits]

Author: Jon Roelofs
Date: 2020-05-26T15:42:32-06:00
New Revision: 1e06b169be3e59799b8dcaf16d1d03bd4c12da42

URL: https://github.com/llvm/llvm-project/commit/1e06b169be3e59799b8dcaf16d1d03bd4c12da42
DIFF: https://github.com/llvm/llvm-project/commit/1e06b169be3e59799b8dcaf16d1d03bd4c12da42.diff

LOG: [clang][docs] Document additional bits of libc that -ffreestanding envs must provide

Differential Revision: https://reviews.llvm.org/D80436

Added: 
    

Modified: 
    clang/docs/CommandGuide/clang.rst

Removed: 
    


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diff  --git a/clang/docs/CommandGuide/clang.rst b/clang/docs/CommandGuide/clang.rst
index 6947450beb43..de0e0eda9097 100644
--- a/clang/docs/CommandGuide/clang.rst
+++ b/clang/docs/CommandGuide/clang.rst
@@ -246,7 +246,9 @@ Language Selection and Mode Options
 .. option:: -ffreestanding
 
  Indicate that the file should be compiled for a freestanding, not a hosted,
- environment.
+ environment. Note that it is assumed that a freestanding environment will
+ additionally provide `memcpy`, `memmove`, `memset` and `memcmp`
+ implementations, as these are needed for efficient codegen for many programs.
 
 .. option:: -fno-builtin