test-release.sh ninja install does builds in Phase 3

[rorth]

When running test-release.sh on Linux/sparc64 (although this happens everywhere), I noticed that in Phase3, ninja install actually does builds. This is unexpected, and made way worse because it passes on neither -j<N> options nor -v, so you cannot see what actually happens.

Missing the -j<N> even badly broke the Linux/sparc64 build which is on a somewhat resource-constrained system. For that reason, the build is run with -j12 while the system has 24 cores. When it comes to Phase3, however, a large part of the build (flang in particular) is run with the full parallelism, which totally overwhelms the memory resources of the system and ultimately causes the build to fail.

flang has always been sort of nightmare on every system because the source files are quite big and compilation way more memory intensive than every other part of LLVM.

[llvmbot]

@llvm/issue-subscribers-infrastructure

Author: Rainer Orth (rorth)

When running `test-release.sh` on Linux/sparc64 (although this happens everywhere), I noticed that in Phase3, `ninja install` actually does builds. This is unexpected, and made way worse because it passes on neither `-j<N>` options nor `-v`, so you cannot see what actually happens.

Missing the -j<N> even badly broke the Linux/sparc64 build which is on a somewhat resource-constrained system. For that reason, the build is run with -j12 while the system has 24 cores. When it comes to Phase3, however, a large part of the build (flang in particular) is run with the full parallelism, which totally overwhelms the memory resources of the system and ultimately causes the build to fail.

flang has always been sort of nightmare on every system because the source files are quite big and compilation way more memory intensive than every other part of LLVM.

[rorth]

FWIW, I've successfully used the following patch to move the builds back out of ninja install:

--- test-release-18.sh.dist	2024-01-24 07:36:14.000000000 +0100
+++ test-release-18.sh	2024-02-07 20:05:12.035652340 +0100
@@ -537,6 +537,11 @@ function build_llvmCore() {
         InstallTarget="$InstallTarget install-runtimes"
       fi
     fi
+    if [ "$Phase" -eq "3" ]; then
+      # Build everything at once, with the proper parallelism and verbosity,
+      # in Phase 3.
+      BuildTarget=
+    fi
 
     cd $ObjDir
     echo "# Compiling llvm $Release-$RC $Flavor"

[tstellar]

@rorth Can you submit this fix in a PR?