diff options
Diffstat (limited to 'gcc/ada/gnat_ugn.texi')
| -rw-r--r-- | gcc/ada/gnat_ugn.texi | 97 |
1 files changed, 56 insertions, 41 deletions
diff --git a/gcc/ada/gnat_ugn.texi b/gcc/ada/gnat_ugn.texi index 4a1baf2aadf..e440ed517ed 100644 --- a/gcc/ada/gnat_ugn.texi +++ b/gcc/ada/gnat_ugn.texi @@ -487,7 +487,9 @@ Creating Unit Tests Using gnattest * Tagged Types Substitutability Testing:: * Testing with Contracts:: * Additional Tests:: +@ifclear vms * Support for other platforms/run-times:: +@end ifclear * Current Limitations:: Other Utility Programs @@ -4306,10 +4308,8 @@ means that no limit applies. @cindex @option{-gnatn} (@command{gcc}) Activate inlining for subprograms for which pragma @code{Inline} is specified. This inlining is performed by the GCC back-end. An optional -digit sets the inlining level: 1 for moderate inlining across modules, -which is a good compromise between compilation times and performances -at run time, and 2 for full inlining across modules, which may bring -about longer compilation times. If no inlining level is specified, +digit sets the inlining level: 1 for moderate inlining across modules +or 2 for full inlining across modules. If no inlining level is specified, the compiler will pick it based on the optimization level. @item -gnatN @@ -7335,21 +7335,28 @@ For the source file naming rules, @xref{File Naming Rules}. @table @option @c !sort! -@item -gnatn +@item -gnatn[12] @cindex @option{-gnatn} (@command{gcc}) @ifclear vms The @code{n} here is intended to suggest the first syllable of the word ``inline''. @end ifclear GNAT recognizes and processes @code{Inline} pragmas. However, for the -inlining to actually occur, optimization must be enabled. To enable -inlining of subprograms specified by pragma @code{Inline}, +inlining to actually occur, optimization must be enabled and, in order +to enable inlining of subprograms specified by pragma @code{Inline}, you must also specify this switch. In the absence of this switch, GNAT does not attempt inlining and does not need to access the bodies of subprograms for which @code{pragma Inline} is specified if they are not in the current unit. +You can optionally specify the inlining level: 1 for moderate inlining across +modules, which is a good compromise between compilation times and performances +at run time, or 2 for full inlining across modules, which may bring about +longer compilation times. If no inlining level is specified, the compiler will +pick it based on the optimization level: 1 for @option{-O1}, @option{-O2} or +@option{-Os} and 2 for @option{-O3}. + If you specify this switch the compiler will access these bodies, creating an extra source dependency for the resulting object file, and where possible, the call will be inlined. @@ -10733,19 +10740,22 @@ Note: The @option{-fno-inline-functions-called-once} switch can be used to prevent inlining of subprograms local to the unit and called once from within it if @option{-O1} is used. -Note regarding the use of @option{-O3}: There is no difference in inlining -behavior between @option{-O2} and @option{-O3} for subprograms with an explicit -pragma @code{Inline} assuming the use of @option{-gnatn} -or @option{-gnatN} (the switches that activate inlining). If you have used -pragma @code{Inline} in appropriate cases, then it is usually much better -to use @option{-O2} and @option{-gnatn} and avoid the use of @option{-O3} which -in this case only has the effect of inlining subprograms you did not -think should be inlined. We often find that the use of @option{-O3} slows -down code by performing excessive inlining, leading to increased instruction -cache pressure from the increased code size. So the bottom line here is -that you should not automatically assume that @option{-O3} is better than -@option{-O2}, and indeed you should use @option{-O3} only if tests show that -it actually improves performance. +Note regarding the use of @option{-O3}: @option{-gnatn} is made up of two +sub-switches @option{-gnatn1} and @option{-gnatn2} that can be directly +specified in lieu of it, @option{-gnatn} being translated into one of them +based on the optimization level. With @option{-O2} or below, @option{-gnatn} +is equivalent to @option{-gnatn1} which activates pragma @code{Inline} with +moderate inlining across modules. With @option{-O3}, @option{-gnatn} is +equivalent to @option{-gnatn2} which activates pragma @code{Inline} with +full inlining across modules. If you have used pragma @code{Inline} in appropriate cases, then it is usually much better to use @option{-O2} and @option{-gnatn} and avoid the use of @option{-O3} which has the additional +effect of inlining subprograms you did not think should be inlined. We have +found that the use of @option{-O3} may slow down the compilation and increase +the code size by performing excessive inlining, leading to increased +instruction cache pressure from the increased code size and thus minor +performance improvements. So the bottom line here is that you should not +automatically assume that @option{-O3} is better than @option{-O2}, and +indeed you should use @option{-O3} only if tests show that it actually +improves performance for your program. @node Vectorization of loops @subsection Vectorization of loops @@ -18099,7 +18109,9 @@ is installed at its default location. * Tagged Types Substitutability Testing:: * Testing with Contracts:: * Additional Tests:: +@ifclear vms * Support for other platforms/run-times:: +@end ifclear * Current Limitations:: @end menu @@ -18408,7 +18420,7 @@ as passed to gnattest when generating the test driver. Passing it to the driver generated on the first example: @smallexample -test_runner --stub-default=pass +test_runner --skeleton-default=pass @end smallexample makes both tests pass, even the unimplemented one. @@ -18613,6 +18625,7 @@ gnatmake -Pmixing/test_driver.gpr mixing/test_runner @end smallexample +@ifclear vms @node Support for other platforms/run-times @section Support for other platforms/run-times @@ -18625,12 +18638,15 @@ such as Zero FootPrint (ZFP), a simplified harness is generated. Two variables are used to tell the underlying AUnit framework how to generate the test harness: @code{PLATFORM}, which identifies the target, and @code{RUNTIME}, used to determine the run-time library for which the harness -is generated. For example, the following options are used to generate the -AUnit test harness for a PowerPC ELF target using the ZFP run-time library: +is generated. Corresponding prefix should also be used when calling +@command{gnattest} for non-native targets. For example, the following options +are used to generate the AUnit test harness for a PowerPC ELF target using +the ZFP run-time library: @smallexample -gnattest -Psimple.gpr -XPLATFORM=powerpc-elf -XRUNTIME=zfp +powerpc-elf-gnattest -Psimple.gpr -XPLATFORM=powerpc-elf -XRUNTIME=zfp @end smallexample +@end ifclear @node Current Limitations @section Current Limitations @@ -18642,7 +18658,6 @@ The tool currently does not support following features: @itemize @bullet @item generic tests for generic packages and package instantiations @item tests for protected subprograms and entries -@item generating test packages for code that is not conformant with ada 2005 @end itemize @@ -18676,13 +18691,13 @@ package, in file s-dimmks.ads. type Mks_Type is new Long_Long_Float with Dimension_System => ( - (Meter, 'm'), - (Kilogram, "kg"), - (Second, 's'), - (Ampere, 'A'), - (Kelvin, 'K'), - (Mole, "mol"), - (Candela, "cd")); + (Unit_Name => Meter, Unit_Symbol => 'm', Dim_Symbol => 'L'), + (Unit_Name => Kilogram, Unit_Symbol => "kg", Dim_Symbol => 'M'), + (Unit_Name => Second, Unit_Symbol => 's', Dim_Symbol => 'T'), + (Unit_Name => Ampere, Unit_Symbol => 'A', Dim_Symbol => 'I'), + (Unit_Name => Kelvin, Unit_Symbol => 'K', Dim_Symbol => "Theta"), + (Unit_Name => Mole, Unit_Symbol => "mol", Dim_Symbol => 'N'), + (Unit_Name => Candela, Unit_Symbol => "cd", Dim_Symbol => 'J')); @end smallexample @noindent @@ -18691,8 +18706,8 @@ conventional units. For example: @smallexample @c ada subtype Length is Mks_Type with - Dimension => ('m', - Meter => 1, + Dimension => (Symbol => 'm', + Meter => 1, others => 0); @end smallexample @noindent @@ -18704,10 +18719,10 @@ The package also defines conventional names for values of each unit, for example: @smallexample @c ada - m : constant Length := 1.0; - kg : constant Mass := 1.0; - s : constant Time := 1.0; - A : constant Electric_Current := 1.0; + m : constant Length := 1.0; + kg : constant Mass := 1.0; + s : constant Time := 1.0; + A : constant Electric_Current := 1.0; @end smallexample @noindent @@ -18775,13 +18790,13 @@ are rejected with the following diagnoses: @smallexample Distance := 5.0; >>> dimensions mismatch in assignment - >>> left-hand side has dimensions (1, 0, 0, 0, 0, 0, 0) + >>> left-hand side has dimension [L] >>> right-hand side is dimensionless Distance := 5.0 * kg: >>> dimensions mismatch in assignment - >>> left-hand side has dimensions (1, 0, 0, 0, 0, 0, 0) - >>> right-hand side has dimensions (0, 1, 0, 0, 0, 0, 0) + >>> left-hand side has dimension [L] + >>> right-hand side has dimension [M] @end smallexample @noindent |