1 files changed, 33 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMAsmPrinter.cpp b/llvm/lib/Target/ARM/ARMAsmPrinter.cpp
index db6eefdb999..27d2c4b356d 100644
--- a/llvm/lib/Target/ARM/ARMAsmPrinter.cpp
+++ b/llvm/lib/Target/ARM/ARMAsmPrinter.cpp
@@ -97,6 +97,13 @@ void ARMAsmPrinter::EmitXXStructor(const DataLayout &DL, const Constant *CV) {
   OutStreamer->EmitValue(E, Size);
 }
 
+void ARMAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
+  if (PromotedGlobals.count(GV))
+    // The global was promoted into a constant pool. It should not be emitted.
+    return;
+  AsmPrinter::EmitGlobalVariable(GV);
+}
+
 /// runOnMachineFunction - This uses the EmitInstruction()
 /// method to print assembly for each instruction.
 ///
@@ -109,6 +116,12 @@ bool ARMAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
   const Function* F = MF.getFunction();
   const TargetMachine& TM = MF.getTarget();
 
+  // Collect all globals that had their storage promoted to a constant pool.
+  // Functions are emitted before variables, so this accumulates promoted
+  // globals from all functions in PromotedGlobals.
+  for (auto *GV : AFI->getGlobalsPromotedToConstantPool())
+    PromotedGlobals.insert(GV);
+  
   // Calculate this function's optimization goal.
   unsigned OptimizationGoal;
   if (F->hasFnAttribute(Attribute::OptimizeNone))
@@ -1002,6 +1015,26 @@ EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
 
   ARMConstantPoolValue *ACPV = static_cast<ARMConstantPoolValue*>(MCPV);
 
+  if (ACPV->isPromotedGlobal()) {
+    // This constant pool entry is actually a global whose storage has been
+    // promoted into the constant pool. This global may be referenced still
+    // by debug information, and due to the way AsmPrinter is set up, the debug
+    // info is immutable by the time we decide to promote globals to constant
+    // pools. Because of this, we need to ensure we emit a symbol for the global
+    // with private linkage (the default) so debug info can refer to it.
+    //
+    // However, if this global is promoted into several functions we must ensure
+    // we don't try and emit duplicate symbols!
+    auto *ACPC = cast<ARMConstantPoolConstant>(ACPV);
+    auto *GV = ACPC->getPromotedGlobal();
+    if (!EmittedPromotedGlobalLabels.count(GV)) {
+      MCSymbol *GVSym = getSymbol(GV);
+      OutStreamer->EmitLabel(GVSym);
+      EmittedPromotedGlobalLabels.insert(GV);
+    }
+    return EmitGlobalConstant(DL, ACPC->getPromotedGlobalInit());
+  }
+
   MCSymbol *MCSym;
   if (ACPV->isLSDA()) {
     MCSym = getCurExceptionSym();