commit 4c4789be5e64fab09bb88de81b7e35db83ae1cb3
author Saleem Abdulrasool <compnerd@compnerd.org> Thu Jan 30 04:46:41 2014 +0000
committer Saleem Abdulrasool <compnerd@compnerd.org> Thu Jan 30 04:46:41 2014 +0000
tree 262f251cb46890237e220f28d56d82f41049909b
parent 15d16d809b46dbb328b8c30b212d921d8989d325

ARM IAS: support .object_arch

The .object_arch directive indicates an alternative architecture to be specified
in the object file.  The directive does *not* effect the enabled feature bits
for the object file generation.  This is particularly useful when the code
performs runtime detection and would like to indicate a lower architecture as
the requirements than the actual instructions used.

llvm-svn: 200451

llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp

diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
index 151d48d..44b56fb 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
@@ -136,6 +136,7 @@
   virtual void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
                                     StringRef StrinValue);
   virtual void emitArch(unsigned Arch);
+  virtual void emitObjectArch(unsigned Arch);
   virtual void emitFPU(unsigned FPU);
   virtual void emitInst(uint32_t Inst, char Suffix = '\0');
   virtual void finishAttributeSection();
@@ -249,6 +250,9 @@
 void ARMTargetAsmStreamer::emitArch(unsigned Arch) {
   OS << "\t.arch\t" << GetArchName(Arch) << "\n";
 }
+void ARMTargetAsmStreamer::emitObjectArch(unsigned Arch) {
+  OS << "\t.object_arch\t" << GetArchName(Arch) << '\n';
+}
 void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
   OS << "\t.fpu\t" << GetFPUName(FPU) << "\n";
 }
@@ -300,6 +304,7 @@
   StringRef CurrentVendor;
   unsigned FPU;
   unsigned Arch;
+  unsigned EmittedArch;
   SmallVector<AttributeItem, 64> Contents;
 
   const MCSection *AttributeSection;
@@ -411,6 +416,7 @@
   virtual void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
                                     StringRef StringValue);
   virtual void emitArch(unsigned Arch);
+  virtual void emitObjectArch(unsigned Arch);
   virtual void emitFPU(unsigned FPU);
   virtual void emitInst(uint32_t Inst, char Suffix = '\0');
   virtual void finishAttributeSection();
@@ -421,8 +427,9 @@
 
 public:
   ARMTargetELFStreamer(MCStreamer &S)
-      : ARMTargetStreamer(S), CurrentVendor("aeabi"), FPU(ARM::INVALID_FPU),
-        Arch(ARM::INVALID_ARCH), AttributeSection(0) {}
+    : ARMTargetStreamer(S), CurrentVendor("aeabi"), FPU(ARM::INVALID_FPU),
+      Arch(ARM::INVALID_ARCH), EmittedArch(ARM::INVALID_ARCH),
+      AttributeSection(0) {}
 };
 
 /// Extend the generic ELFStreamer class so that it can emit mapping symbols at
@@ -714,10 +721,17 @@
 void ARMTargetELFStreamer::emitArch(unsigned Value) {
   Arch = Value;
 }
+void ARMTargetELFStreamer::emitObjectArch(unsigned Value) {
+  EmittedArch = Value;
+}
 void ARMTargetELFStreamer::emitArchDefaultAttributes() {
   using namespace ARMBuildAttrs;
+
   setAttributeItem(CPU_name, GetArchDefaultCPUName(Arch), false);
-  setAttributeItem(CPU_arch, GetArchDefaultCPUArch(Arch), false);
+  if (EmittedArch == ARM::INVALID_ARCH)
+    setAttributeItem(CPU_arch, GetArchDefaultCPUArch(Arch), false);
+  else
+    setAttributeItem(CPU_arch, GetArchDefaultCPUArch(EmittedArch), false);
 
   switch (Arch) {
   case ARM::ARMV2: