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| author | Alex Richardson <alexrichardson@google.com> | 2023-06-07 13:25:01 -0700 |
|---|---|---|
| committer | Alex Richardson <alexrichardson@google.com> | 2023-06-07 15:55:50 -0700 |
| commit | 4a9d0c33bd3e532aa369d8362a7faf1ba3cfd26a (patch) | |
| tree | 0203281924dfec359631df7f2d1cc9c3d5cff2f4 | |
| parent | acb933b5ac129932a37ab79b6e672b5156dd1510 (diff) | |
| download | lk-4a9d0c33bd3e532aa369d8362a7faf1ba3cfd26a.tar.gz | |
[make] Build with -ffreestanding
We should build with -ffreestanding since we are building an OS kernel and
cannot rely on all hosted environment functionality being present.
Specifically this fixes a compilation error with clang caused by the
the #include_next <limits.h>:
```
In file included from target/pc-x86/config.c:9:
In file included from dev/include/dev/driver.h:10:
In file included from lib/libc/include/sys/types.h:10:
In file included from lib/libc/include/limits.h:5:
In file included from /usr/lib/llvm-15/lib/clang/15.0.7/include/limits.h:21:
/usr/include/limits.h:26:10: fatal error: 'bits/libc-header-start.h' file not found
#include <bits/libc-header-start.h>
```
The flag fixes this issue by ensuring that __STDC_HOSTED__ is no longer set
to 1, so Clang's limits.h will not try to include the host system one.
| -rw-r--r-- | engine.mk | 3 |
1 files changed, 3 insertions, 0 deletions
@@ -66,6 +66,9 @@ GLOBAL_COMPILEFLAGS := -g -include $(CONFIGHEADER) GLOBAL_COMPILEFLAGS += -Wextra -Wall -Werror=return-type -Wshadow -Wdouble-promotion GLOBAL_COMPILEFLAGS += -Wno-multichar -Wno-unused-parameter -Wno-unused-function -Wno-unused-label GLOBAL_COMPILEFLAGS += -fno-common +# Build with -ffreestanding since we are building an OS kernel and cannot +# rely on all hosted environment functionality being present. +GLOBAL_COMPILEFLAGS += -ffreestanding GLOBAL_CFLAGS := --std=gnu11 -Werror-implicit-function-declaration -Wstrict-prototypes -Wwrite-strings GLOBAL_CPPFLAGS := --std=c++14 -fno-exceptions -fno-rtti -fno-threadsafe-statics GLOBAL_ASMFLAGS := -DASSEMBLY |