[mips] Fix inconsistent .cprestore behaviour between direct object emission and assem...

Summary:
Direct object emission has an initialization order problem where an
InitMCObjectFile is called after MipsTargetELFStreamer determines whether
PIC is enabled by default or not. There doesn't seem to be point that
initializes all cases so split the responsibility between
MipsTargetELFStreamer and MipsAsmPrinter.

Reviewers: sdardis

Subscribers: dsanders, llvm-commits, sdardis

Differential Revision: http://reviews.llvm.org/D19728

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268737 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp b/lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
index 58c1f0ee4eeda2dee559b42209f55e1be4498fe1..23c46351b82a536ea65b9cb1282c51c7fd93e3b5 100644 (file)
--- a/lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
+++ b/lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
@@ -652,6 +652,14 @@ MipsTargetELFStreamer::MipsTargetELFStreamer(MCStreamer &S,
                                              const MCSubtargetInfo &STI)
     : MipsTargetStreamer(S), MicroMipsEnabled(false), STI(STI) {
   MCAssembler &MCA = getStreamer().getAssembler();
+
+  // It's possible that MCObjectFileInfo isn't fully initialized at this point
+  // due to an initialization order problem where LLVMTargetMachine creates the
+  // target streamer before TargetLoweringObjectFile calls
+  // InitializeMCObjectFileInfo. There doesn't seem to be a single place that
+  // covers all cases so this statement covers most cases and direct object
+  // emission must call setPic() once MCObjectFileInfo has been initialized. The
+  // cases we don't handle here are covered by MipsAsmPrinter.
   Pic = MCA.getContext().getObjectFileInfo()->getRelocM() == Reloc::PIC_;
 
   const FeatureBitset &Features = STI.getFeatureBits();

diff --git a/lib/Target/Mips/MipsAsmPrinter.cpp b/lib/Target/Mips/MipsAsmPrinter.cpp
index cd35b0caee52467325b8f4eba3d3826b7edb06d0..24afb8863a63e9fa65140377fb7f5246ddecf0df 100644 (file)
--- a/lib/Target/Mips/MipsAsmPrinter.cpp
+++ b/lib/Target/Mips/MipsAsmPrinter.cpp
@@ -669,6 +669,12 @@ printRegisterList(const MachineInstr *MI, int opNum, raw_ostream &O) {
 }
 
 void MipsAsmPrinter::EmitStartOfAsmFile(Module &M) {
+  MipsTargetStreamer &TS = getTargetStreamer();
+
+  // MipsTargetStreamer has an initialization order problem when emitting an
+  // object file directly (see MipsTargetELFStreamer for full details). Work
+  // around it by re-initializing the PIC state here.
+  TS.setPic(OutContext.getObjectFileInfo()->getRelocM());
 
   // Compute MIPS architecture attributes based on the default subtarget
   // that we'd have constructed. Module level directives aren't LTO
@@ -684,14 +690,14 @@ void MipsAsmPrinter::EmitStartOfAsmFile(Module &M) {
   bool IsABICalls = STI.isABICalls();
   const MipsABIInfo &ABI = MTM.getABI();
   if (IsABICalls) {
-    getTargetStreamer().emitDirectiveAbiCalls();
+    TS.emitDirectiveAbiCalls();
     Reloc::Model RM = TM.getRelocationModel();
     // FIXME: This condition should be a lot more complicated that it is here.
     //        Ideally it should test for properties of the ABI and not the ABI
     //        itself.
     //        For the moment, I'm only correcting enough to make MIPS-IV work.
     if (RM == Reloc::Static && !ABI.IsN64())
-      getTargetStreamer().emitDirectiveOptionPic0();
+      TS.emitDirectiveOptionPic0();
   }
 
   // Tell the assembler which ABI we are using
@@ -702,8 +708,8 @@ void MipsAsmPrinter::EmitStartOfAsmFile(Module &M) {
   // NaN: At the moment we only support:
   // 1. .nan legacy (default)
   // 2. .nan 2008
-  STI.isNaN2008() ? getTargetStreamer().emitDirectiveNaN2008()
-                  : getTargetStreamer().emitDirectiveNaNLegacy();
+  STI.isNaN2008() ? TS.emitDirectiveNaN2008()
+                  : TS.emitDirectiveNaNLegacy();
 
   // TODO: handle O64 ABI
 
@@ -716,19 +722,19 @@ void MipsAsmPrinter::EmitStartOfAsmFile(Module &M) {
                                                           ELF::SHT_PROGBITS, 0));
   }
 
-  getTargetStreamer().updateABIInfo(STI);
+  TS.updateABIInfo(STI);
 
   // We should always emit a '.module fp=...' but binutils 2.24 does not accept
   // it. We therefore emit it when it contradicts the ABI defaults (-mfpxx or
   // -mfp64) and omit it otherwise.
   if (ABI.IsO32() && (STI.isABI_FPXX() || STI.isFP64bit()))
-    getTargetStreamer().emitDirectiveModuleFP();
+    TS.emitDirectiveModuleFP();
 
   // We should always emit a '.module [no]oddspreg' but binutils 2.24 does not
   // accept it. We therefore emit it when it contradicts the default or an
   // option has changed the default (i.e. FPXX) and omit it otherwise.
   if (ABI.IsO32() && (!STI.useOddSPReg() || STI.isABI_FPXX()))
-    getTargetStreamer().emitDirectiveModuleOddSPReg();
+    TS.emitDirectiveModuleOddSPReg();
 }
 
 void MipsAsmPrinter::emitInlineAsmStart() const {

diff --git a/lib/Target/Mips/MipsTargetStreamer.h b/lib/Target/Mips/MipsTargetStreamer.h
index a60943b8a411acaa81f5348634f0db7faf5618b6..2b39da6ade5cda36272240a9380b5522ac8c8553 100644 (file)
--- a/lib/Target/Mips/MipsTargetStreamer.h
+++ b/lib/Target/Mips/MipsTargetStreamer.h
@@ -24,6 +24,9 @@ struct MipsABIFlagsSection;
 class MipsTargetStreamer : public MCTargetStreamer {
 public:
   MipsTargetStreamer(MCStreamer &S);
+
+  virtual void setPic(bool Value) {}
+
   virtual void emitDirectiveSetMicroMips();
   virtual void emitDirectiveSetNoMicroMips();
   virtual void emitDirectiveSetMips16();
@@ -260,6 +263,8 @@ public:
   MCELFStreamer &getStreamer();
   MipsTargetELFStreamer(MCStreamer &S, const MCSubtargetInfo &STI);
 
+  void setPic(bool Value) override { Pic = Value; }
+
   void emitLabel(MCSymbol *Symbol) override;
   void emitAssignment(MCSymbol *Symbol, const MCExpr *Value) override;
   void finish() override;

diff --git a/test/MC/Mips/init-order-bug.ll b/test/MC/Mips/init-order-bug.ll
new file mode 100644 (file)
index 0000000..9682dce
--- /dev/null
+++ b/test/MC/Mips/init-order-bug.ll
@@ -0,0 +1,12 @@
+; RUN: llc -mtriple=mipsel-linux-gnu -relocation-model=pic -filetype=asm < %s | \
+; RUN:     llvm-mc -triple=mipsel-linux-gnu -relocation-model=pic -filetype=obj | \
+; RUN:     llvm-objdump -d - | FileCheck %s
+; RUN: llc -mtriple=mipsel-linux-gnu -relocation-model=pic -filetype=obj < %s | \
+; RUN:     llvm-objdump -d - | FileCheck %s
+
+define void @foo() {
+  call void asm sideeffect "\09.cprestore 512", "~{$1}"()
+  ret void
+}
+
+; CHECK: sw $gp, 512($sp)