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author | Stephen Hines <srhines@google.com> | 2014-07-21 00:45:20 -0700 |
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committer | Stephen Hines <srhines@google.com> | 2014-07-25 00:48:57 -0700 |
commit | cd81d94322a39503e4a3e87b6ee03d4fcb3465fb (patch) | |
tree | 81b7dd2bb4370a392f31d332a566c903b5744764 /lib/Transforms/IPO/GlobalOpt.cpp | |
parent | 0c5f13c0c4499eaf42ab5e9e2ceabd4e20e36861 (diff) | |
download | external_llvm-cd81d94322a39503e4a3e87b6ee03d4fcb3465fb.zip external_llvm-cd81d94322a39503e4a3e87b6ee03d4fcb3465fb.tar.gz external_llvm-cd81d94322a39503e4a3e87b6ee03d4fcb3465fb.tar.bz2 |
Update LLVM for rebase to r212749.
Includes a cherry-pick of:
r212948 - fixes a small issue with atomic calls
Change-Id: Ib97bd980b59f18142a69506400911a6009d9df18
Diffstat (limited to 'lib/Transforms/IPO/GlobalOpt.cpp')
-rw-r--r-- | lib/Transforms/IPO/GlobalOpt.cpp | 45 |
1 files changed, 31 insertions, 14 deletions
diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp index ae80c43..c1d0d3b 100644 --- a/lib/Transforms/IPO/GlobalOpt.cpp +++ b/lib/Transforms/IPO/GlobalOpt.cpp @@ -17,6 +17,7 @@ #include "llvm/ADT/DenseMap.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/SmallSet.h" #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/Statistic.h" #include "llvm/Analysis/ConstantFolding.h" @@ -1699,9 +1700,6 @@ static bool TryToShrinkGlobalToBoolean(GlobalVariable *GV, Constant *OtherVal) { /// possible. If we make a change, return true. bool GlobalOpt::ProcessGlobal(GlobalVariable *GV, Module::global_iterator &GVI) { - if (!GV->isDiscardableIfUnused()) - return false; - // Do more involved optimizations if the global is internal. GV->removeDeadConstantUsers(); @@ -1910,7 +1908,7 @@ bool GlobalOpt::OptimizeFunctions(Module &M) { for (Module::iterator FI = M.begin(), E = M.end(); FI != E; ) { Function *F = FI++; // Functions without names cannot be referenced outside this module. - if (!F->hasName() && !F->isDeclaration()) + if (!F->hasName() && !F->isDeclaration() && !F->hasLocalLinkage()) F->setLinkage(GlobalValue::InternalLinkage); F->removeDeadConstantUsers(); if (F->isDefTriviallyDead()) { @@ -1944,11 +1942,18 @@ bool GlobalOpt::OptimizeFunctions(Module &M) { bool GlobalOpt::OptimizeGlobalVars(Module &M) { bool Changed = false; + + SmallSet<const Comdat *, 8> NotDiscardableComdats; + for (const GlobalVariable &GV : M.globals()) + if (const Comdat *C = GV.getComdat()) + if (!GV.isDiscardableIfUnused()) + NotDiscardableComdats.insert(C); + for (Module::global_iterator GVI = M.global_begin(), E = M.global_end(); GVI != E; ) { GlobalVariable *GV = GVI++; // Global variables without names cannot be referenced outside this module. - if (!GV->hasName() && !GV->isDeclaration()) + if (!GV->hasName() && !GV->isDeclaration() && !GV->hasLocalLinkage()) GV->setLinkage(GlobalValue::InternalLinkage); // Simplify the initializer. if (GV->hasInitializer()) @@ -1958,7 +1963,12 @@ bool GlobalOpt::OptimizeGlobalVars(Module &M) { GV->setInitializer(New); } - Changed |= ProcessGlobal(GV, GVI); + if (GV->isDiscardableIfUnused()) { + if (const Comdat *C = GV->getComdat()) + if (NotDiscardableComdats.count(C)) + continue; + Changed |= ProcessGlobal(GV, GVI); + } } return Changed; } @@ -1980,10 +1990,13 @@ isSimpleEnoughValueToCommit(Constant *C, static bool isSimpleEnoughValueToCommitHelper(Constant *C, SmallPtrSet<Constant*, 8> &SimpleConstants, const DataLayout *DL) { - // Simple integer, undef, constant aggregate zero, global addresses, etc are - // all supported. - if (C->getNumOperands() == 0 || isa<BlockAddress>(C) || - isa<GlobalValue>(C)) + // Simple global addresses are supported, do not allow dllimport or + // thread-local globals. + if (auto *GV = dyn_cast<GlobalValue>(C)) + return !GV->hasDLLImportStorageClass() && !GV->isThreadLocal(); + + // Simple integer, undef, constant aggregate zero, etc are all supported. + if (C->getNumOperands() == 0 || isa<BlockAddress>(C)) return true; // Aggregate values are safe if all their elements are. @@ -2054,8 +2067,7 @@ static bool isSimpleEnoughPointerToCommit(Constant *C) { return false; if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) - // Do not allow weak/*_odr/linkonce/dllimport/dllexport linkage or - // external globals. + // Do not allow weak/*_odr/linkonce linkage or external globals. return GV->hasUniqueInitializer(); if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) { @@ -2846,14 +2858,19 @@ bool GlobalOpt::OptimizeGlobalAliases(Module &M) { I != E;) { Module::alias_iterator J = I++; // Aliases without names cannot be referenced outside this module. - if (!J->hasName() && !J->isDeclaration()) + if (!J->hasName() && !J->isDeclaration() && !J->hasLocalLinkage()) J->setLinkage(GlobalValue::InternalLinkage); // If the aliasee may change at link time, nothing can be done - bail out. if (J->mayBeOverridden()) continue; Constant *Aliasee = J->getAliasee(); - GlobalValue *Target = cast<GlobalValue>(Aliasee->stripPointerCasts()); + GlobalValue *Target = dyn_cast<GlobalValue>(Aliasee->stripPointerCasts()); + // We can't trivially replace the alias with the aliasee if the aliasee is + // non-trivial in some way. + // TODO: Try to handle non-zero GEPs of local aliasees. + if (!Target) + continue; Target->removeDeadConstantUsers(); // Make all users of the alias use the aliasee instead. |