Auto merge of #56642 - nikic:llvm-6, r=alexcrichton

Bump minimum required LLVM version to 6.0

Based on the discussion in #55842, while the overall position of Rust wrt LLVM continues to be contentious, there does seem to be a consensus that there is no need for continued support of LLVM 5. This PR bumps our version requirement to LLVM 6.0 and makes Travis run against that.

I hope that this is going to unblock #52694. If I understand correctly, while this issue still exists in LLVM 6, Ubuntu has backported the relevant patch.

r? @alexcrichton

.travis.yml

@@ -16,7 +16,7 @@ matrix:
   fast_finish: true
   include:
     # Images used in testing PR and try-build should be run first.
-    - env: IMAGE=x86_64-gnu-llvm-5.0 RUST_BACKTRACE=1
+    - env: IMAGE=x86_64-gnu-llvm-6.0 RUST_BACKTRACE=1
       if: type = pull_request OR branch = auto
 
     - env: IMAGE=dist-x86_64-linux DEPLOY=1

src/bootstrap/native.rs

@@ -278,11 +278,11 @@ fn check_llvm_version(builder: &Builder, llvm_config: &Path) {
     let mut parts = version.split('.').take(2)
         .filter_map(|s| s.parse::<u32>().ok());
     if let (Some(major), Some(_minor)) = (parts.next(), parts.next()) {
-        if major >= 5 {
+        if major >= 6 {
             return
         }
     }
-    panic!("\n\nbad LLVM version: {}, need >=5.0\n\n", version)
+    panic!("\n\nbad LLVM version: {}, need >=6.0\n\n", version)
 }
 
 fn configure_cmake(builder: &Builder,

src/ci/docker/x86_64-gnu-llvm-6.0/Dockerfile

@@ -11,7 +11,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   cmake \
   sudo \
   gdb \
-  llvm-5.0-tools \
+  llvm-6.0-tools \
   libedit-dev \
   zlib1g-dev \
   xz-utils
@@ -22,6 +22,6 @@ RUN sh /scripts/sccache.sh
 # using llvm-link-shared due to libffi issues -- see #34486
 ENV RUST_CONFIGURE_ARGS \
       --build=x86_64-unknown-linux-gnu \
-      --llvm-root=/usr/lib/llvm-5.0 \
+      --llvm-root=/usr/lib/llvm-6.0 \
       --enable-llvm-link-shared
 ENV RUST_CHECK_TARGET check

src/librustc_codegen_llvm/builder.rs

@@ -1024,17 +1024,11 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
 
     fn minnum(&mut self, lhs: &'ll Value, rhs: &'ll Value) -> &'ll Value {
         self.count_insn("minnum");
-        unsafe {
-            let instr = llvm::LLVMRustBuildMinNum(self.llbuilder, lhs, rhs);
-            instr.expect("LLVMRustBuildMinNum is not available in LLVM version < 6.0")
-        }
+        unsafe { llvm::LLVMRustBuildMinNum(self.llbuilder, lhs, rhs) }
     }
     fn maxnum(&mut self, lhs: &'ll Value, rhs: &'ll Value) -> &'ll Value {
         self.count_insn("maxnum");
-        unsafe {
-            let instr = llvm::LLVMRustBuildMaxNum(self.llbuilder, lhs, rhs);
-            instr.expect("LLVMRustBuildMaxNum is not available in LLVM version < 6.0")
-        }
+        unsafe { llvm::LLVMRustBuildMaxNum(self.llbuilder, lhs, rhs) }
     }
 
     fn select(

src/librustc_codegen_llvm/context.rs

@@ -10,7 +10,6 @@
 
 use attributes;
 use llvm;
-use llvm_util;
 use rustc::dep_graph::DepGraphSafe;
 use rustc::hir;
 use debuginfo;
@@ -446,10 +445,6 @@ impl MiscMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         attributes::apply_target_cpu_attr(self, llfn)
     }
 
-    fn closure_env_needs_indirect_debuginfo(&self) -> bool {
-        llvm_util::get_major_version() < 6
-    }
-
     fn create_used_variable(&self) {
         let name = const_cstr!("llvm.used");
         let section = const_cstr!("llvm.metadata");

src/librustc_codegen_llvm/llvm/ffi.rs

@@ -1222,12 +1222,12 @@ extern "C" {
         B: &Builder<'a>,
         LHS: &'a Value,
         LHS: &'a Value,
-    ) -> Option<&'a Value>;
+    ) -> &'a Value;
     pub fn LLVMRustBuildMaxNum(
         B: &Builder<'a>,
         LHS: &'a Value,
         LHS: &'a Value,
-    ) -> Option<&'a Value>;
+    ) -> &'a Value;
 
     // Atomic Operations
     pub fn LLVMRustBuildAtomicLoad(B: &Builder<'a>,

src/librustc_codegen_ssa/mir/mod.rs

@@ -610,35 +610,13 @@ fn arg_local_refs<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
             };
             let upvar_tys = upvar_substs.upvar_tys(def_id, tcx);
 
-            // Store the pointer to closure data in an alloca for debuginfo
-            // because that's what the llvm.dbg.declare intrinsic expects.
-
-            // FIXME(eddyb) this shouldn't be necessary but SROA seems to
-            // mishandle DW_OP_plus not preceded by DW_OP_deref, i.e., it
-            // doesn't actually strip the offset when splitting the closure
-            // environment into its components so it ends up out of bounds.
-            // (cuviper) It seems to be fine without the alloca on LLVM 6 and later.
-            let env_alloca = !env_ref && bx.closure_env_needs_indirect_debuginfo();
-            let env_ptr = if env_alloca {
-                let scratch = PlaceRef::alloca(bx,
-                    bx.layout_of(tcx.mk_mut_ptr(arg.layout.ty)),
-                    "__debuginfo_env_ptr");
-                bx.store(place.llval, scratch.llval, scratch.align);
-                scratch.llval
-            } else {
-                place.llval
-            };
-
             for (i, (decl, ty)) in mir.upvar_decls.iter().zip(upvar_tys).enumerate() {
                 let byte_offset_of_var_in_env = closure_layout.fields.offset(i).bytes();
 
                 let ops = bx.debuginfo_upvar_decls_ops_sequence(byte_offset_of_var_in_env);
 
                 // The environment and the capture can each be indirect.
-
-                // FIXME(eddyb) see above why we sometimes have to keep
-                // a pointer in an alloca for debuginfo atm.
-                let mut ops = if env_ref || env_alloca { &ops[..] } else { &ops[1..] };
+                let mut ops = if env_ref { &ops[..] } else { &ops[1..] };
 
                 let ty = if let (true, &ty::Ref(_, ty, _)) = (decl.by_ref, &ty.sty) {
                     ty
@@ -648,7 +626,7 @@ fn arg_local_refs<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
                 };
 
                 let variable_access = VariableAccess::IndirectVariable {
-                    alloca: env_ptr,
+                    alloca: place.llval,
                     address_operations: &ops
                 };
                 bx.declare_local(

src/librustc_codegen_ssa/traits/misc.rs

@@ -32,7 +32,6 @@ pub trait MiscMethods<'tcx>: BackendTypes {
     fn stats(&self) -> &RefCell<Stats>;
     fn consume_stats(self) -> RefCell<Stats>;
     fn codegen_unit(&self) -> &Arc<CodegenUnit<'tcx>>;
-    fn closure_env_needs_indirect_debuginfo(&self) -> bool;
     fn used_statics(&self) -> &RefCell<Vec<Self::Value>>;
     fn set_frame_pointer_elimination(&self, llfn: Self::Value);
     fn apply_target_cpu_attr(&self, llfn: Self::Value);

src/rustllvm/ArchiveWrapper.cpp

@@ -216,16 +216,11 @@ LLVMRustWriteArchive(char *Dst, size_t NumMembers,
       Members.push_back(std::move(*MOrErr));
     }
   }
+
   auto Result = writeArchive(Dst, Members, WriteSymbtab, Kind, true, false);
-#if LLVM_VERSION_GE(6, 0)
   if (!Result)
     return LLVMRustResult::Success;
   LLVMRustSetLastError(toString(std::move(Result)).c_str());
-#else
-  if (!Result.second)
-    return LLVMRustResult::Success;
-  LLVMRustSetLastError(Result.second.message().c_str());
-#endif
 
   return LLVMRustResult::Failure;
 }

src/rustllvm/PassWrapper.cpp

@@ -17,21 +17,15 @@
 
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/IR/AutoUpgrade.h"
 #include "llvm/IR/AssemblyAnnotationWriter.h"
+#include "llvm/IR/IntrinsicInst.h"
 #include "llvm/Support/CBindingWrapping.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
-
-#if LLVM_VERSION_GE(6, 0)
-#include "llvm/CodeGen/TargetSubtargetInfo.h"
-#include "llvm/IR/IntrinsicInst.h"
-#else
-#include "llvm/Target/TargetSubtargetInfo.h"
-#endif
-
 #include "llvm/Transforms/IPO/AlwaysInliner.h"
 #include "llvm/Transforms/IPO/FunctionImport.h"
 #include "llvm/Transforms/Utils/FunctionImportUtils.h"
@@ -198,13 +192,9 @@ GEN_SUBTARGETS
 
 extern "C" bool LLVMRustHasFeature(LLVMTargetMachineRef TM,
                                    const char *Feature) {
-#if LLVM_VERSION_GE(6, 0)
   TargetMachine *Target = unwrap(TM);
   const MCSubtargetInfo *MCInfo = Target->getMCSubtargetInfo();
   return MCInfo->checkFeatures(std::string("+") + Feature);
-#else
-  return false;
-#endif
 }
 
 enum class LLVMRustCodeModel {
@@ -392,13 +382,9 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
     Options.ThreadModel = ThreadModel::Single;
   }
 
-#if LLVM_VERSION_GE(6, 0)
   Options.EmitStackSizeSection = EmitStackSizeSection;
 
   Optional<CodeModel::Model> CM;
-#else
-  CodeModel::Model CM = CodeModel::Model::Default;
-#endif
   if (RustCM != LLVMRustCodeModel::None)
     CM = fromRust(RustCM);
   TargetMachine *TM = TheTarget->createTargetMachine(

src/rustllvm/RustWrapper.cpp

@@ -297,11 +297,7 @@ extern "C" void LLVMRustRemoveFunctionAttributes(LLVMValueRef Fn,
 // enable fpmath flag UnsafeAlgebra
 extern "C" void LLVMRustSetHasUnsafeAlgebra(LLVMValueRef V) {
   if (auto I = dyn_cast<Instruction>(unwrap<Value>(V))) {
-#if LLVM_VERSION_GE(6, 0)
     I->setFast(true);
-#else
-    I->setHasUnsafeAlgebra(true);
-#endif
   }
 }
 
@@ -1437,7 +1433,6 @@ LLVMRustBuildVectorReduceFMax(LLVMBuilderRef B, LLVMValueRef Src, bool NoNaN) {
   return wrap(unwrap(B)->CreateFPMaxReduce(unwrap(Src), NoNaN));
 }
 
-#if LLVM_VERSION_GE(6, 0)
 extern "C" LLVMValueRef
 LLVMRustBuildMinNum(LLVMBuilderRef B, LLVMValueRef LHS, LLVMValueRef RHS) {
     return wrap(unwrap(B)->CreateMinNum(unwrap(LHS),unwrap(RHS)));
@@ -1446,13 +1441,3 @@ extern "C" LLVMValueRef
 LLVMRustBuildMaxNum(LLVMBuilderRef B, LLVMValueRef LHS, LLVMValueRef RHS) {
     return wrap(unwrap(B)->CreateMaxNum(unwrap(LHS),unwrap(RHS)));
 }
-#else
-extern "C" LLVMValueRef
-LLVMRustBuildMinNum(LLVMBuilderRef, LLVMValueRef, LLVMValueRef) {
-   return nullptr;
-}
-extern "C" LLVMValueRef
-LLVMRustBuildMaxNum(LLVMBuilderRef, LLVMValueRef, LLVMValueRef) {
-   return nullptr;
-}
-#endif

src/test/codegen/function-arguments.rs

@@ -10,7 +10,6 @@
 
 // compile-flags: -C no-prepopulate-passes
 // ignore-tidy-linelength
-// min-llvm-version 6.0
 
 #![crate_type = "lib"]
 #![feature(custom_attribute)]

src/test/codegen/issue-44056-macos-tls-align.rs

@@ -11,7 +11,6 @@
 // ignore-tidy-linelength
 // only-macos
 // no-system-llvm
-// min-llvm-version 6.0
 // compile-flags: -O
 
 #![crate_type = "rlib"]

src/test/codegen/issue-45222.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 // compile-flags: -O
-// min-llvm-version 6.0
 
 #![crate_type = "lib"]
 

src/test/codegen/issue-45466.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 // compile-flags: -O
-// min-llvm-version 6.0
 
 #![crate_type="rlib"]
 

src/test/codegen/simd-intrinsic-generic-gather.rs

@@ -10,7 +10,6 @@
 
 // ignore-emscripten
 // ignore-tidy-linelength
-// min-llvm-version 6.0
 
 // compile-flags: -C no-prepopulate-passes
 

src/test/codegen/simd-intrinsic-generic-scatter.rs

@@ -10,7 +10,6 @@
 
 // ignore-emscripten
 // ignore-tidy-linelength
-// min-llvm-version 6.0
 
 // compile-flags: -C no-prepopulate-passes
 

src/test/codegen/vtabletype.rs

@@ -14,7 +14,6 @@
 // ignore-tidy-linelength
 // ignore-windows
 // ignore-macos
-// min-llvm-version 6.0
 
 // compile-flags: -g -C no-prepopulate-passes
 

src/test/run-pass/simd/simd-intrinsic-generic-gather.rs

@@ -10,7 +10,6 @@
 
 // run-pass
 // ignore-emscripten
-// min-llvm-version 6.0
 
 // Test that the simd_{gather,scatter} intrinsics produce the correct results.
 

src/test/run-pass/sse2.rs

@@ -8,11 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![allow(stable_features)]
-// min-llvm-version 6.0
-// ^ needs MCSubtargetInfo::checkFeatures()
 // ignore-cloudabi no std::env
 
+#![allow(stable_features)]
 #![feature(cfg_target_feature)]
 
 use std::env;

src/test/ui/target-feature-gate.rs

@@ -24,7 +24,6 @@
 // gate-test-mips_target_feature
 // gate-test-mmx_target_feature
 // gate-test-wasm_target_feature
-// min-llvm-version 6.0
 
 #[target_feature(enable = "avx512bw")]
 //~^ ERROR: currently unstable

src/test/ui/target-feature-gate.stderr

@@ -1,5 +1,5 @@
 error[E0658]: the target feature `avx512bw` is currently unstable (see issue #44839)
-  --> $DIR/target-feature-gate.rs:29:18
+  --> $DIR/target-feature-gate.rs:28:18
    |
 LL | #[target_feature(enable = "avx512bw")]
    |                  ^^^^^^^^^^^^^^^^^^^