[ThinLTO] Refine fix to avoid renaming of uses in inline assembly.
Summary:
Refine the workaround from r266877 that attempts to prevent
renaming of locals in inline assembly, so that in addition to looking
for a llvm.used local value, that there is at least one inline assembly
call in the module. Otherwise, debug functions added to the llvm.used
can block importing/exporting unnecessarily.
Reviewers: joker.eph
Subscribers: llvm-commits, joker.eph
Differential Revision: http://reviews.llvm.org/D19573
llvm-svn: 267717
diff --git a/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp b/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp
index 4280e96..33ce5cc 100644
--- a/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp
+++ b/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp
@@ -13,6 +13,8 @@
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/FunctionImportUtils.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/Instructions.h"
using namespace llvm;
/// Checks if we should import SGV as a definition, otherwise import as a
@@ -211,25 +213,31 @@
}
void FunctionImportGlobalProcessing::processGlobalsForThinLTO() {
- // We cannot currently promote or rename anything that is in llvm.used,
- // since any such value may have a use that won't see the new name.
- // Specifically, any uses within inline assembly are not visible to the
- // compiler. Prevent changing any such values on the exporting side,
+ // We cannot currently promote or rename anything used in inline assembly,
+ // which are not visible to the compiler. Detect a possible case by looking
+ // for a llvm.used local value, in conjunction with an inline assembly call
+ // in the module. Prevent changing any such values on the exporting side,
// since we would already have guarded against an import from this module by
// suppressing its index generation. See comments on what is required
// in order to implement a finer grained solution in
// ModuleSummaryIndexBuilder::ModuleSummaryIndexBuilder().
SmallPtrSet<GlobalValue *, 8> Used;
collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ false);
+ bool LocalIsUsed = false;
for (GlobalValue *V : Used) {
- if (!V->hasLocalLinkage())
- continue;
// We would have blocked importing from this module by suppressing index
// generation.
- assert(!isPerformingImport() &&
+ assert((!V->hasLocalLinkage() || !isPerformingImport()) &&
"Should have blocked importing from module with local used");
- return;
+ if ((LocalIsUsed |= V->hasLocalLinkage()))
+ break;
}
+ if (LocalIsUsed)
+ for (auto &F : M)
+ for (auto &I : instructions(F))
+ if (const CallInst *CallI = dyn_cast<CallInst>(&I))
+ if (CallI->isInlineAsm())
+ return;
for (GlobalVariable &GV : M.globals())
processGlobalForThinLTO(GV);