#### 7.2.1 Syntax and Descriptions of test directives

Test directives appear within comments in a test source file and begin with `dg-`. Some of these are defined within DejaGnu and others are local to the GCC testsuite.

The order in which test directives appear in a test can be important: directives local to GCC sometimes override information used by the DejaGnu directives, which know nothing about the GCC directives, so the DejaGnu directives must precede GCC directives.

Several test directives include selectors (see Selectors) which are usually preceded by the keyword `target` or `xfail`.

##### 7.2.1.1 Specify how to build the test

`{ dg-do` do-what-keyword`[{ target/xfail` selector`}] }`
  do-what-keyword specifies how the test is compiled and whether it is executed. It is one of:
  `preprocess`
    Compile with `-E` to run only the preprocessor.
  `compile`
    Compile with `-S` to produce an assembly code file.
  `assemble`
    Compile with `-c` to produce a relocatable object file.
  `link`
    Compile, assemble, and link to produce an executable file.
  `run`
    Produce and run an executable file, which is expected to return an exit code of 0.

  The default is `compile`. That can be overridden for a set of tests by redefining `dg-do-what-default` within the `.exp` file for those tests.

  If the directive includes the optional ``{ target selector }`' then the test is skipped unless the target system matches the selector.

  If do-what-keyword is `run` and the directive includes the optional ``{ xfail selector }`' and the selector is met then the test is expected to fail. The `xfail` clause is ignored for other values of do-what-keyword; those tests can use directive `dg-xfail-if`.

##### 7.2.1.2 Specify additional compiler options

`{ dg-options` options`[{ target` selector`}] }`
  This DejaGnu directive provides a list of compiler options, to be used if the target system matches selector, that replace the default options used for this set of tests.
`{ dg-add-options` feature`... }`
  Add any compiler options that are needed to access certain features. This directive does nothing on targets that enable the features by default, or that don't provide them at all. It must come after all `dg-options` directives. For supported values of feature see Add Options.
`{ dg-additional-options` options`[{ target` selector`}] }`
  This directive provides a list of compiler options, to be used if the target system matches selector, that are added to the default options used for this set of tests.

##### 7.2.1.3 Modify the test timeout value

The normal timeout limit, in seconds, is found by searching the following in order:

- the value defined by an earlier `dg-timeout` directive in the test
- variable tool_timeout defined by the set of tests
- gcc,timeout set in the target board
- 300

`{ dg-timeout` n`[{target` selector`}] }`
  Set the time limit for the compilation and for the execution of the test to the specified number of seconds.
`{ dg-timeout-factor` x`[{ target` selector`}] }`
  Multiply the normal time limit for compilation and execution of the test by the specified floating-point factor.

##### 7.2.1.4 Skip a test for some targets

`{ dg-skip-if` comment`{` selector`} [{` include-opts`} [{` exclude-opts`}]] }`
  Arguments include-opts and exclude-opts are lists in which each element is a string of zero or more GCC options. Skip the test if all of the following conditions are met:
  - the test system is included in selector
  - for at least one of the option strings in include-opts, every option from that string is in the set of options with which the test would be compiled; use ``"*"`' for an include-opts list that matches any options; that is the default if include-opts is not specified
  - for each of the option strings in exclude-opts, at least one option from that string is not in the set of options with which the test would be compiled; use ``""`' for an empty exclude-opts list; that is the default if exclude-opts is not specified

  For example, to skip a test if option `-Os` is present:

                /* { dg-skip-if "" { *-*-* }  { "-Os" } { "" } } */

  To skip a test if both options `-O2` and `-g` are present:

                /* { dg-skip-if "" { *-*-* }  { "-O2 -g" } { "" } } */

  To skip a test if either `-O2` or `-O3` is present:

                /* { dg-skip-if "" { *-*-* }  { "-O2" "-O3" } { "" } } */

  To skip a test unless option `-Os` is present:

                /* { dg-skip-if "" { *-*-* }  { "*" } { "-Os" } } */

  To skip a test if either `-O2` or `-O3` is used with `-g` but not if `-fpic` is also present:

                /* { dg-skip-if "" { *-*-* }  { "-O2 -g" "-O3 -g" } { "-fpic" } } */

`{ dg-require-effective-target` keyword`[{` selector`}] }`
  Skip the test if the test target, including current multilib flags, is not covered by the effective-target keyword. If the directive includes the optional ``{ selector }`' then the effective-target test is only performed if the target system matches the selector. This directive must appear after any `dg-do` directive in the test and before any `dg-additional-sources` directive. See Effective-Target Keywords.
`{ dg-require-`support `args }`
  Skip the test if the target does not provide the required support. These directives must appear after any `dg-do` directive in the test and before any `dg-additional-sources` directive. They require at least one argument, which can be an empty string if the specific procedure does not examine the argument. See Require Support, for a complete list of these directives.

##### 7.2.1.5 Expect a test to fail for some targets

`{ dg-xfail-if` comment`{` selector`} [{` include-opts`} [{` exclude-opts`}]] }`
  Expect the test to fail if the conditions (which are the same as for `dg-skip-if`) are met. This does not affect the execute step.
`{ dg-xfail-run-if` comment`{` selector`} [{` include-opts`} [{` exclude-opts`}]] }`
  Expect the execute step of a test to fail if the conditions (which are the same as for `dg-skip-if`) are met.

##### 7.2.1.6 Expect the test executable to fail

`{ dg-shouldfail` comment`[{` selector`} [{` include-opts`} [{` exclude-opts`}]]] }`
  Expect the test executable to return a nonzero exit status if the conditions (which are the same as for `dg-skip-if`) are met.

##### 7.2.1.7 Verify compiler messages

`{ dg-error` regexp`[`comment`[{ target/xfail` selector`} [`line`] }]] }`
  This DejaGnu directive appears on a source line that is expected to get an error message, or else specifies the source line associated with the message. If there is no message for that line or if the text of that message is not matched by regexp then the check fails and comment is included in the `FAIL` message. The check does not look for the string ``error`' unless it is part of regexp.
`{ dg-warning` regexp`[`comment`[{ target/xfail` selector`} [`line`] }]] }`
  This DejaGnu directive appears on a source line that is expected to get a warning message, or else specifies the source line associated with the message. If there is no message for that line or if the text of that message is not matched by regexp then the check fails and comment is included in the `FAIL` message. The check does not look for the string ``warning`' unless it is part of regexp.
`{ dg-message` regexp`[`comment`[{ target/xfail` selector`} [`line`] }]] }`
  The line is expected to get a message other than an error or warning. If there is no message for that line or if the text of that message is not matched by regexp then the check fails and comment is included in the `FAIL` message.
`{ dg-bogus` regexp`[`comment`[{ target/xfail` selector`} [`line`] }]] }`
  This DejaGnu directive appears on a source line that should not get a message matching regexp, or else specifies the source line associated with the bogus message. It is usually used with ``xfail`' to indicate that the message is a known problem for a particular set of targets.
`{ dg-excess-errors` comment`[{ target/xfail` selector`}] }`
  This DejaGnu directive indicates that the test is expected to fail due to compiler messages that are not handled by ``dg-error`', ``dg-warning`' or ``dg-bogus`'. For this directive ``xfail`' has the same effect as ``target`'.
`{ dg-prune-output` regexp`}`
  Prune messages matching regexp from the test output.

##### 7.2.1.8 Verify output of the test executable

`{ dg-output` regexp`[{ target/xfail` selector`}] }`
  This DejaGnu directive compares regexp to the combined output that the test executable writes to `stdout` and `stderr`.

##### 7.2.1.9 Specify additional files for a test

`{ dg-additional-files "`filelist`" }`
  Specify additional files, other than source files, that must be copied to the system where the compiler runs.
`{ dg-additional-sources "`filelist`" }`
  Specify additional source files to appear in the compile line following the main test file.

##### 7.2.1.10 Add checks at the end of a test

`{ dg-final {` local-directive`} }`
  This DejaGnu directive is placed within a comment anywhere in the source file and is processed after the test has been compiled and run. Multiple ``dg-final`' commands are processed in the order in which they appear in the source file. See Final Actions, for a list of directives that can be used within `dg-final`.