Rollup merge of #78848 - DevJPM:ci-llvm-9, r=nikic

Bump minimal supported LLVM version to 9

This bumps the minimal tested llvm version to 9.
This should enable supporting newer LLVM features (and CPU extensions).

This was motived by #78361 having to drop features because of LLVM 8 not supporting certain CPU extensions yet.
This was declared relatively uncontroversial on [Zulip](https://rust-lang.zulipchat.com/#narrow/stream/182449-t-compiler.2Fhelp/topic/Min.20Supported.20LLVM.20Upgrade.20Process.3F/near/215957859).

Paging ````@eddyb```` because there was a comment in the [dockerfile](https://github.com/rust-lang/rust/blob/master/src/ci/docker/host-x86_64/x86_64-gnu-llvm-8/Dockerfile#L42) describing a hack (which I don't quite understand) which was also blocked by not having LLVM 9.

1 files changed, 0 insertions, 16 deletions

diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index 938eb19faef..9b0c176b692 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -124,9 +124,7 @@ extern "C" LLVMValueRef LLVMRustGetOrInsertFunction(LLVMModuleRef M,
   return wrap(unwrap(M)
                   ->getOrInsertFunction(StringRef(Name, NameLen),
                                         unwrap<FunctionType>(FunctionTy))
-#if LLVM_VERSION_GE(9, 0)
                   .getCallee()
-#endif
   );
 }
 
@@ -251,11 +249,7 @@ extern "C" void LLVMRustAddDereferenceableOrNullCallSiteAttr(LLVMValueRef Instr,
 extern "C" void LLVMRustAddByValCallSiteAttr(LLVMValueRef Instr, unsigned Index,
                                              LLVMTypeRef Ty) {
   CallBase *Call = unwrap<CallBase>(Instr);
-#if LLVM_VERSION_GE(9, 0)
   Attribute Attr = Attribute::getWithByValType(Call->getContext(), unwrap(Ty));
-#else
-  Attribute Attr = Attribute::get(Call->getContext(), Attribute::ByVal);
-#endif
   Call->addAttribute(Index, Attr);
 }
 
@@ -296,11 +290,7 @@ extern "C" void LLVMRustAddDereferenceableOrNullAttr(LLVMValueRef Fn,
 extern "C" void LLVMRustAddByValAttr(LLVMValueRef Fn, unsigned Index,
                                      LLVMTypeRef Ty) {
   Function *F = unwrap<Function>(Fn);
-#if LLVM_VERSION_GE(9, 0)
   Attribute Attr = Attribute::getWithByValType(F->getContext(), unwrap(Ty));
-#else
-  Attribute Attr = Attribute::get(F->getContext(), Attribute::ByVal);
-#endif
   F->addAttribute(Index, Attr);
 }
 
@@ -616,11 +606,9 @@ static DISubprogram::DISPFlags fromRust(LLVMRustDISPFlags SPFlags) {
   if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagOptimized)) {
     Result |= DISubprogram::DISPFlags::SPFlagOptimized;
   }
-#if LLVM_VERSION_GE(9, 0)
   if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagMainSubprogram)) {
     Result |= DISubprogram::DISPFlags::SPFlagMainSubprogram;
   }
-#endif
 
   return Result;
 }
@@ -744,10 +732,6 @@ extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateFunction(
       DITemplateParameterArray(unwrap<MDTuple>(TParam));
   DISubprogram::DISPFlags llvmSPFlags = fromRust(SPFlags);
   DINode::DIFlags llvmFlags = fromRust(Flags);
-#if LLVM_VERSION_LT(9, 0)
-  if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagMainSubprogram))
-    llvmFlags |= DINode::DIFlags::FlagMainSubprogram;
-#endif
   DISubprogram *Sub = Builder->createFunction(
       unwrapDI<DIScope>(Scope),
       StringRef(Name, NameLen),