| This directory contains tests for link-time optimization (LTO). |
| Tests in this directory may span multiple files, so the naming of |
| the files is significant. |
| |
| The name of every file must end with '_N' where N is an integer. |
| All the files with the same name base and different _N suffixes |
| will be compiled separately and linked together to form the final |
| executable. |
| |
| By default, each set of files will be compiled with list of |
| options listed in LTO_OPTIONS (../../lib/lto.exp), which can be |
| overwritten in the shell environment or using the 'dg-lto-options' |
| command in the main file of the set (i.e., the file with _0 |
| suffix). |
| |
| For example, given the files a_0.C a_1.C a_2.C, they will be |
| compiled as: |
| |
| $ g++ -c <flags> a_0.C |
| $ g++ -c <flags> a_1.C |
| $ g++ -c <flags> a_2.C |
| $ g++ -o <executable> a_0.o a_1.o a_2.o |
| |
| Tests that do not need more than one file are a special case |
| where there is a single file named 'foo_0.C'. |
| |
| The only supported dg-lto-do option are 'assemble', 'run' and 'link'. |
| Additionally, these can only be used in the main file. If |
| 'assemble' is used, only the individual object files are |
| generated. If 'link' is used, the final executable is generated |
| but not executed (in this case, function main() needs to exist |
| but it does not need to do anything). If 'run' is used, the |
| final executable is generated and the resulting binary executed. |
| |
| The default value for dg-lto-do is 'run'. |
