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 Selecting targets to which a test applies) which are usually preceded by the keyword target or xfail.

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.

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 Features for dg-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.

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.

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 [ target {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 Keywords describing target attributes.

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 Variants of dg-require-support, for a complete list of these directives.

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.

Expect the compiler to crash#

dg-ice {comment [ {selector } [ {include-opts } [ {exclude-opts }]]] }: Expect the compiler to crash with an internal compiler error and return a nonzero exit status if the conditions (which are the same as for dg-skip-if) are met. Used for tests that test bugs that have not been fixed yet.

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.

Verify compiler messages#

Where line is an accepted argument for these commands, a value of 0 can be used if there is no line associated with the message.

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-note {regexp [comment [ target/xfail {selector } [line] ]] }

The line is expected to get a note 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.

By default, any excess note messages are pruned, meaning their appearance doesn’t trigger excess errors. However, if dg-note is used at least once in a testcase, they’re not pruned and instead must all be handled explicitly. Thus, if looking for just single instances of messages with note: prefixes without caring for all of them, use dg-message "note: [...]" instead of dg-note, or use dg-note together with dg-prune-output "note: ".

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-line {linenumvar }

This DejaGnu directive sets the variable linenumvar to the line number of the source line. The variable linenumvar can then be used in subsequent dg-error, dg-warning, dg-message, dg-note and dg-bogus directives. For example:

int a;   /* { dg-line first_def_a } */
float a; /* { dg-error "conflicting types of" } */
/* { dg-message "previous declaration of" "" { target *-*-* } first_def_a } */

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, dg-message, dg-note 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.

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.

Specify environment variables for a test#

dg-set-compiler-env-var {var_name "var_value" }: Specify that the environment variable var_name needs to be set to var_value before invoking the compiler on the test file.
dg-set-target-env-var {var_name "var_value" }: Specify that the environment variable var_name needs to be set to var_value before execution of the program created by the test.

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.

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 Commands for use in dg-final, for a list of directives that can be used within dg-final.