Don't add extra passes into the function pass manager

Exception for specific cases like linting, additional passes should
be going into the module pass manager (even if they are function
passes). The separate function pass manager is only used for very
early optimization passes.

Rather than apparending passes to the MPM, use the OptimizerLast
and EnabledOnOptLevel0 pass manager builder extension hooks, which
allow adding passes directly before finalization (alias
canonicalization and name-anon-globals).

The main effect and purpose of this change is to add sanitizer
passes at the end of the pipeline, which is where they belong.
In LLVM 9 the address sanitizer can't be used as a pass in the
early function pass manager, because it has a dependence on a
module-level analysis pass.

1 files changed, 17 insertions, 0 deletions

diff --git a/src/rustllvm/PassWrapper.cpp b/src/rustllvm/PassWrapper.cpp
index a2c427a9dba..7d20086d9a2 100644
--- a/src/rustllvm/PassWrapper.cpp
+++ b/src/rustllvm/PassWrapper.cpp
@@ -99,6 +99,23 @@ void LLVMRustPassManagerBuilderPopulateThinLTOPassManager(
   unwrap(PMBR)->populateThinLTOPassManager(*unwrap(PMR));
 }
 
+extern "C"
+void LLVMRustAddLastExtensionPasses(
+    LLVMPassManagerBuilderRef PMBR, LLVMPassRef *Passes, size_t NumPasses) {
+  auto AddExtensionPasses = [Passes, NumPasses](
+      const PassManagerBuilder &Builder, PassManagerBase &PM) {
+    for (size_t I = 0; I < NumPasses; I++) {
+      PM.add(unwrap(Passes[I]));
+    }
+  };
+  // Add the passes to both of the pre-finalization extension points,
+  // so they are run for optimized and non-optimized builds.
+  unwrap(PMBR)->addExtension(PassManagerBuilder::EP_OptimizerLast,
+                             AddExtensionPasses);
+  unwrap(PMBR)->addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
+                             AddExtensionPasses);
+}
+
 #ifdef LLVM_COMPONENT_X86
 #define SUBTARGET_X86 SUBTARGET(X86)
 #else