[commit: ghc] master: Fix LLVM TBAA metadata (90fae01)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/90fae01c326bf8b0802b4e8968f84886be4e1380/ghc

>---------------------------------------------------------------

commit 90fae01c326bf8b0802b4e8968f84886be4e1380
Author: Demi Obenour <demiobenour at gmail.com>
Date:   Fri Dec 9 15:41:59 2016 -0500

    Fix LLVM TBAA metadata
    
    Accesses through a Cmm local are currently reported as having the
    "other" type, which can only alias other "other" accesses.  However,
    this assumption is incorrect, which can result in silent bad LLVM
    codegen.
    
    Fixes #9308.
    Fixes #9504.
    
    Test Plan: GHC CI
    
    Reviewers: rwbarton, austin, bgamari
    
    Reviewed By: bgamari
    
    Subscribers: michalt, thomie
    
    Differential Revision: https://phabricator.haskell.org/D2758
    
    GHC Trac Issues: #9125, #9308, #9504


>---------------------------------------------------------------

90fae01c326bf8b0802b4e8968f84886be4e1380
 compiler/llvmGen/LlvmCodeGen/CodeGen.hs |  6 ++----
 compiler/llvmGen/LlvmCodeGen/Regs.hs    | 14 ++++++--------
 2 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/compiler/llvmGen/LlvmCodeGen/CodeGen.hs b/compiler/llvmGen/LlvmCodeGen/CodeGen.hs
index 7b610c0..d88d234 100644
--- a/compiler/llvmGen/LlvmCodeGen/CodeGen.hs
+++ b/compiler/llvmGen/LlvmCodeGen/CodeGen.hs
@@ -845,8 +845,7 @@ genStore addr@(CmmMachOp (MO_Sub _) [
 
 -- generic case
 genStore addr val
-    = do other <- getTBAAMeta otherN
-         genStore_slow addr val other
+    = getTBAAMeta topN >>= genStore_slow addr val
 
 -- | CmmStore operation
 -- This is a special case for storing to a global register pointer
@@ -1494,8 +1493,7 @@ genLoad atomic e@(CmmMachOp (MO_Sub _) [
 
 -- generic case
 genLoad atomic e ty
-    = do other <- getTBAAMeta otherN
-         genLoad_slow atomic e ty other
+    = getTBAAMeta topN >>= genLoad_slow atomic e ty
 
 -- | Handle CmmLoad expression.
 -- This is a special case for loading from a global register pointer
diff --git a/compiler/llvmGen/LlvmCodeGen/Regs.hs b/compiler/llvmGen/LlvmCodeGen/Regs.hs
index 8ac4153..1ee9fc1 100644
--- a/compiler/llvmGen/LlvmCodeGen/Regs.hs
+++ b/compiler/llvmGen/LlvmCodeGen/Regs.hs
@@ -6,7 +6,7 @@
 
 module LlvmCodeGen.Regs (
         lmGlobalRegArg, lmGlobalRegVar, alwaysLive,
-        stgTBAA, baseN, stackN, heapN, rxN, otherN, tbaa, getTBAA
+        stgTBAA, baseN, stackN, heapN, rxN, topN, tbaa, getTBAA
     ) where
 
 #include "HsVersions.h"
@@ -102,21 +102,19 @@ stgTBAA
     , (heapN,  fsLit "heap",  Just topN)
     , (rxN,    fsLit "rx",    Just heapN)
     , (baseN,  fsLit "base",  Just topN)
-    -- FIX: Not 100% sure about 'others' place. Might need to be under 'heap'.
-    -- OR I think the big thing is Sp is never aliased, so might want
-    -- to change the hieracy to have Sp on its own branch that is never
-    -- aliased (e.g never use top as a TBAA node).
-    , (otherN, fsLit "other", Just topN)
+    -- FIX: Not 100% sure if this heirarchy is complete.  I think the big thing
+    -- is Sp is never aliased, so might want to change the hierarchy to have Sp
+    -- on its own branch that is never aliased (e.g never use top as a TBAA
+    -- node).
     ]
 
 -- | Id values
-topN, stackN, heapN, rxN, baseN, otherN :: Unique
+topN, stackN, heapN, rxN, baseN :: Unique
 topN   = getUnique (fsLit "LlvmCodeGen.Regs.topN")
 stackN = getUnique (fsLit "LlvmCodeGen.Regs.stackN")
 heapN  = getUnique (fsLit "LlvmCodeGen.Regs.heapN")
 rxN    = getUnique (fsLit "LlvmCodeGen.Regs.rxN")
 baseN  = getUnique (fsLit "LlvmCodeGen.Regs.baseN")
-otherN = getUnique (fsLit "LlvmCodeGen.Regs.otherN")
 
 -- | The TBAA metadata identifier
 tbaa :: LMString