Add support for job pools

Commands can now be assigned to an arbitrary job pool and a limit for
the number of concurrently running jobs in such pools can be provided in
a number of ways:
- via the build command line: qbs --job-limits linker:1
- via the settings: qbs config preferences.jobLimit.linker 1
- in a project file: JobLimit {
                         jobPool: "linker";
                         jobCount: 1
                     }
We provide two job pools ourselves with the cpp module: "compiler" and
"linker".

[ChangeLog] Added the concept of job pools for limiting concurrent
execution of commands by type

Task-number: QBS-743
Change-Id: Ib3f361dbc73093e342bf0eba0daf2079a2b3a8ce
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

1 files changed, 25 insertions, 0 deletions

diff --git a/doc/reference/modules/cpp-module.qdoc b/doc/reference/modules/cpp-module.qdoc
index 0818af28d..386ac7553 100644
--- a/doc/reference/modules/cpp-module.qdoc
+++ b/doc/reference/modules/cpp-module.qdoc
@@ -217,6 +217,31 @@
             This file tag only has an effect with GCC-like toolchains. The linker needs to be
             \c{ld}-compatible.
     \endtable
+
+    \section2 Relevant Job Pools
+    \target cpp-job-pools
+
+    \table
+    \header
+        \li Pool
+        \li Since
+        \li Description
+    \row
+        \li \c{"assembler"}
+        \li 1.13
+        \li The job pool used by rules that run the toolchain's assembler. This is only
+            relevant for direct invocations of the assembler binary, not for running it
+            indirectly via the compiler.
+    \row
+        \li \c{"compiler"}
+        \li 1.13
+        \li The job pool used by rules that run a compiler. All language variants use
+            the same pool.
+    \row
+        \li \c{"linker"}
+        \li 1.13
+        \li The job pool used by rules that run a linker.
+    \endtable
 */
 
 /*!