I have copied gcc output of a simple C program as follows. COLLECT_GCC_OPTIONS has been repeated 3 times. Does it mean the compilation has 3 passes? Which of them is considered for compilation and when? About the following line: COLLECT_GCC_OPTIONS='-v' '-o' 'prog1' '-mtune=generic' '-march=i686' as -V -Qy -o /tmp/ccb2pBgG.o /tmp/ccQNR8AL.s What does the option, "as" mean? ------------------------------------------- /root/tmp3> gcc -v -o prog1 prog1.c Using built-in specs. Target: i686-redhat-linux Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk --disable-dssi --enable-plugin --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-1.5.0.0/jre --enable-libgcj-multifile --enable-java-maintainer-mode --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --disable-libjava-multilib --with-ppl --with-cloog --with-tune=generic --with-arch=i686 --build=i686-redhat-linux Thread model: posix gcc version 4.4.2 20091222 (Red Hat 4.4.2-20) (GCC) COLLECT_GCC_OPTIONS='-v' '-o' 'prog1' '-mtune=generic' '-march=i686' /usr/libexec/gcc/i686-redhat-linux/4.4.2/cc1 -quiet -v prog1.c -quiet -dumpbase prog1.c -mtune=generic -march=i686 -auxbase prog1 -version -o /tmp/ccQNR8AL.s ignoring nonexistent directory "/usr/lib/gcc/i686-redhat-linux/4.4.2/include-fixed" ignoring nonexistent directory "/usr/lib/gcc/i686-redhat-linux/4.4.2/../../../../i686-redhat-linux/include" #include "..." search starts here: #include <...> search starts here: /usr/local/include /usr/lib/gcc/i686-redhat-linux/4.4.2/include /usr/include End of search list. GNU C (GCC) version 4.4.2 20091222 (Red Hat 4.4.2-20) (i686-redhat-linux) compiled by GNU C version 4.4.2 20091222 (Red Hat 4.4.2-20), GMP version 4.3.1, MPFR version 2.4.1. GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 Compiler executable checksum: ce871bdaf8715137a79dafbeccd13c96 COLLECT_GCC_OPTIONS='-v' '-o' 'prog1' '-mtune=generic' '-march=i686' as -V -Qy -o /tmp/ccb2pBgG.o /tmp/ccQNR8AL.s GNU assembler version 2.19.51.0.14 (i686-redhat-linux) using BFD version version 2.19.51.0.14-34.fc12 20090722 COMPILER_PATH=/usr/libexec/gcc/i686-redhat-linux/4.4.2/:/usr/libexec/gcc/i686-redhat-linux/4.4.2/:/usr/libexec/gcc/i686-redhat-linux/:/usr/lib/gcc/i686-redhat-linux/4.4.2/:/usr/lib/gcc/i686-redhat-linux/:/usr/libexec/gcc/i686-redhat-linux/4.4.2/:/usr/libexec/gcc/i686-redhat-linux/:/usr/lib/gcc/i686-redhat-linux/4.4.2/:/usr/lib/gcc/i686-redhat-linux/ LIBRARY_PATH=/usr/lib/gcc/i686-redhat-linux/4.4.2/:/usr/lib/gcc/i686-redhat-linux/4.4.2/:/usr/lib/gcc/i686-redhat-linux/4.4.2/../../../:/lib/:/usr/lib/ COLLECT_GCC_OPTIONS='-v' '-o' 'prog1' '-mtune=generic' '-march=i686' /usr/libexec/gcc/i686-redhat-linux/4.4.2/collect2 --eh-frame-hdr --build-id -m elf_i386 --hash-style=gnu -dynamic-linker /lib/ld-linux.so.2 -o prog1 /usr/lib/gcc/i686-redhat-linux/4.4.2/../../../crt1.o /usr/lib/gcc/i686-redhat-linux/4.4.2/../../../crti.o /usr/lib/gcc/i686-redhat-linux/4.4.2/crtbegin.o -L/usr/lib/gcc/i686-redhat-linux/4.4.2 -L/usr/lib/gcc/i686-redhat-linux/4.4.2 -L/usr/lib/gcc/i686-redhat-linux/4.4.2/../../.. /tmp/ccb2pBgG.o -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed /usr/lib/gcc/i686-redhat-linux/4.4.2/crtend.o /usr/lib/gcc/i686-redhat-linux/4.4.2/../../../crtn.o -------------------------------------------
