Problems and solutions when upgrading XLC from 10.1 to IBM Open XL C/C++ for AIX 17.1.0

In this article, I would like to document the problems encountered when upgrading from IBM XLC 10.1 to XLC 17.1 (IBM Open XL C/C++ for AIX 17.1.0) and how to fix the following 12 errors.If you’ve encountered any other errors, feel free to share your comments with or without a solution.

1. Change cc to ibm-clang

First you need to change all the related cc to ibm-clang in the the global Makefile. for example:

- CC=cc
- CXX=xlC_r
- XCC=xlC_r
- MAKE_SHARED=xlC_r
+ CC=ibm-clang
+ CXX=ibm-clang_r
+ XCC=ibm-clang_r
+ MAKE_SHARED=ibm-clang_r

And check following link of Mapping of options to map new Clang options if any.

2. error: unknown argument: ‘-qmakedep=gcc’

- GEN_DEPENDENTS_OPTIONS=-qmakedep=gcc  -E -MF $@.1 > /dev/null
+ GEN_DEPENDENTS_OPTIONS= -E -MF $@.1 > /dev/null

3. should not return a value [-Wreturn-type]

- return -1;
+ return;

4. error: non-void function ‘main’ should return a value [-Wreturn-type]

- return;
+ return 0;

5. error: unsupported option ‘-G’ for target ‘powerpc64-ibm-aix7.3.0.0’

- LIB_101_FLAGS := -G 
+ LIB_101_FLAGS := -shared -Wl,-G

6. Undefined symbol (libxxxx.so)

- LIB_10_FLAGS := -bexport:$(SRC)/makefiles/xxxx.def
+ LIB_10_FLAGS := -lstdc++ -lm -bexport:$(SRC)/makefiles/xxxx.def

7. unsupported option -qlongdouble

- drv_connect.c.CC_OPTIONS=$(CFLAGS) -qlongdouble -brtl
+ drv_loadfunc.c.CC_OPTIONS=$(CFLAGS) $(IDIR) -brtl

8. Undefined symbol: ._Z8u9_closei

- extern int u9_close(int fd) ;
+ extern "C" int u9_close(int fd) ;

9. ERROR: Undefined symbol: .pow

- CXXLIBES = -lpthread -lC -lstdc++
+ CXXLIBES = -lpthread -lC -lstdc++ -lm

10. ‘main’ (argument array) must be of type ‘char **’

- d_char *argv[];
+ char *argv[];

11. first parameter of ‘main’ (argument count) must be of type ‘int’

- int main(char *argc, char *argv[])
+ int main(int argc, char *argv[])

12. ERROR: Undefined symbol: ._ZdaPv

- LIB_3_LIBS	:= -lverse -llog_nosig
+ LIB_3_LIBS	:= -lverse -llog_nosig -lstdc++