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Add make rules to build LLVM IR from C/C++ sources.

Browse Source 
As a foundation for future work with LLVM's Intermediate Representation (IR),
add new suffix rules that can be used to build .llo (text) or .bco (bitcode)
files from C or C++ sources.  This compilation step uses the same CFLAGS, etc.,
as are used for building .o files, with the exception of optimization flags.
Many of the things we would like to do with IR (e.g., instrumentation) work
better with unoptimized code, so our approach is to build .c->.bco without
optimization and then apply the optimization in post-analysis,
post-instrumentation linking.

The overall result of these changes is:

* one can "make foo.llo" or "make foo.bco" wherever "make foo.o" was supported
* new make variables IR_CFLAGS and IR_CXXFLAGS are available to inspect the
  flags that are used by Clang to generate the IR

These new rules are added unconditionally to our non-POSIX suffix rule set,
since we cannot inspect COMPILER_TYPE in sys.mk.  Future changes that depend
on these rules (e.g., building IR versions of binaries from bsd.prog.mk)
should use COMPILER_TYPE to determine when we can expect IR rules to succeed.

Reviewed by:	emaste, imp
Approved by:	rwatson (mentor)
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D4339
This commit is contained in:
Jonathan Anderson 2016-10-20 15:14:21 +00:00
parent 71e30a3131
commit c867306e60
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=307676
2 changed files with 14 additions and 0 deletions
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12
share/mk/bsd.suffixes.mk
View File

@ -20,12 +20,24 @@
${CC} ${STATIC_CFLAGS} ${CFLAGS} -c ${.IMPSRC} -o ${.TARGET}
${CTFCONVERT_CMD}
.c.bco:
${CC} -emit-llvm ${IR_CFLAGS} -c ${.IMPSRC} -o ${.TARGET}
.c.llo:
${CC} -emit-llvm ${IR_CFLAGS} -S ${.IMPSRC} -o ${.TARGET}
.cc .cpp .cxx .C:
${CXX} ${CXXFLAGS} ${LDFLAGS} ${.IMPSRC} ${LDLIBS} -o ${.TARGET}
.cc.o .cpp.o .cxx.o .C.o:
${CXX} ${STATIC_CXXFLAGS} ${CXXFLAGS} -c ${.IMPSRC} -o ${.TARGET}
.cc.bco .cpp.bco .cxx.bco .C.bco:
${CXX} -emit-llvm ${IR_CXXFLAGS} -c ${.IMPSRC} -o ${.TARGET}
.cc.llo .cpp.llo .cxx.llo .C.llo:
${CXX} -emit-llvm ${IR_CXXFLAGS} -S ${.IMPSRC} -o ${.TARGET}
.m.o:
${OBJC} ${OBJCFLAGS} -c ${.IMPSRC} -o ${.TARGET}
${CTFCONVERT_CMD}

2
share/mk/sys.mk
View File

@ -153,6 +153,7 @@ CFLAGS ?= -O2 -pipe
CFLAGS += -fno-strict-aliasing
.endif
.endif
IR_CFLAGS ?= ${STATIC_CFLAGS:N-O*} ${CFLAGS:N-O*}
PO_CFLAGS ?= ${CFLAGS}
# cp(1) is used to copy source files to ${.OBJDIR}, make sure it can handle
@ -173,6 +174,7 @@ CTFFLAGS += -g
CXX ?= c++
CXXFLAGS ?= ${CFLAGS:N-std=*:N-Wnested-externs:N-W*-prototypes:N-Wno-pointer-sign:N-Wold-style-definition}
IR_CXXFLAGS ?= ${STATIC_CXXFLAGS:N-O*} ${CXXFLAGS:N-O*}
PO_CXXFLAGS ?= ${CXXFLAGS}
DTRACE ?= dtrace