From: Peter Collingbourne <peter@pcc.me.uk>
Date: Thu, 1 Dec 2016 06:53:47 +0000 (+0000)
Subject: Object: Add SF_Executable symbol flag.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=71fc8a346a2ff86ec254eb5b025c1b5c98565c8a;p=llvm

Object: Add SF_Executable symbol flag.

This allows us to remove a few uses of IRObjectFile::getSymbolGV() in
llvm-nm.

While here change host-dependent logic in llvm-nm to target-dependent
logic.

Differential Revision: https://reviews.llvm.org/D27075

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288320 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/Object/SymbolicFile.h b/include/llvm/Object/SymbolicFile.h
index 9655202097b..af62e62c51d 100644
--- a/include/llvm/Object/SymbolicFile.h
+++ b/include/llvm/Object/SymbolicFile.h
@@ -88,7 +88,6 @@ class BasicSymbolRef {
   const SymbolicFile *OwningObject;
 
 public:
-  // FIXME: should we add a SF_Text?
   enum Flags : unsigned {
     SF_None = 0,
     SF_Undefined = 1U << 0,      // Symbol is defined in another object file
@@ -103,6 +102,8 @@ public:
     SF_Thumb = 1U << 8,          // Thumb symbol in a 32-bit ARM binary
     SF_Hidden = 1U << 9,         // Symbol has hidden visibility
     SF_Const = 1U << 10,         // Symbol value is constant
+    SF_Executable = 1U << 11,    // Symbol points to an executable section
+                                 // (IR only)
   };
 
   BasicSymbolRef() : OwningObject(nullptr) { }
diff --git a/lib/Object/ModuleSymbolTable.cpp b/lib/Object/ModuleSymbolTable.cpp
index 5e534af4410..c8b1bb6b775 100644
--- a/lib/Object/ModuleSymbolTable.cpp
+++ b/lib/Object/ModuleSymbolTable.cpp
@@ -109,7 +109,8 @@ void ModuleSymbolTable::CollectAsmSymbols(
   for (auto &KV : Streamer) {
     StringRef Key = KV.first();
     RecordStreamer::State Value = KV.second;
-    uint32_t Res = BasicSymbolRef::SF_None;
+    // FIXME: For now we just assume that all asm symbols are executable.
+    uint32_t Res = BasicSymbolRef::SF_Executable;
     switch (Value) {
     case RecordStreamer::NeverSeen:
       llvm_unreachable("NeverSeen should have been replaced earlier");
@@ -163,6 +164,8 @@ uint32_t ModuleSymbolTable::getSymbolFlags(Symbol S) const {
     if (GVar->isConstant())
       Res |= BasicSymbolRef::SF_Const;
   }
+  if (dyn_cast_or_null<Function>(GV->getBaseObject()))
+    Res |= BasicSymbolRef::SF_Executable;
   if (GV->hasPrivateLinkage())
     Res |= BasicSymbolRef::SF_FormatSpecific;
   if (!GV->hasLocalLinkage())
diff --git a/tools/llvm-nm/llvm-nm.cpp b/tools/llvm-nm/llvm-nm.cpp
index 436cf9cac68..33385e9953e 100644
--- a/tools/llvm-nm/llvm-nm.cpp
+++ b/tools/llvm-nm/llvm-nm.cpp
@@ -313,10 +313,10 @@ static void darwinPrintSymbol(SymbolicFile &Obj, SymbolListT::iterator I,
       NType |= MachO::N_SECT;
       if (SymFlags & SymbolRef::SF_Const)
         NSect = 3;
-      else {
-        IRObjectFile *IRobj = dyn_cast<IRObjectFile>(&Obj);
-        NSect = (getSymbolNMTypeChar(*IRobj, I->Sym) == 't') ? 1 : 2;
-      }
+      else if (SymFlags & SymbolRef::SF_Executable)
+        NSect = 1;
+      else
+        NSect = 2;
     }
     if (SymFlags & SymbolRef::SF_Weak)
       NDesc |= MachO::N_WEAK_DEF;
@@ -882,15 +882,17 @@ static char getSymbolNMTypeChar(MachOObjectFile &Obj, basic_symbol_iterator I) {
   return '?';
 }
 
-static char getSymbolNMTypeChar(const GlobalValue &GV) {
+static char getSymbolNMTypeChar(IRObjectFile &Obj, basic_symbol_iterator I) {
+  uint32_t Flags = I->getFlags();
   // FIXME: should we print 'b'? At the IR level we cannot be sure if this
   // will be in bss or not, but we could approximate.
-  return GV.getValueType()->isFunctionTy() ? 't' : 'd';
-}
-
-static char getSymbolNMTypeChar(IRObjectFile &Obj, basic_symbol_iterator I) {
-  const GlobalValue *GV = Obj.getSymbolGV(I->getRawDataRefImpl());
-  return !GV ? 't' : getSymbolNMTypeChar(*GV);
+  if (Flags & SymbolRef::SF_Executable)
+    return 't';
+  else if (Triple(Obj.getTargetTriple()).isOSDarwin() &&
+           (Flags & SymbolRef::SF_Const))
+    return 's';
+  else
+    return 'd';
 }
 
 static bool isObject(SymbolicFile &Obj, basic_symbol_iterator I) {
@@ -915,12 +917,8 @@ static char getNMTypeChar(SymbolicFile &Obj, basic_symbol_iterator I) {
   char Ret = '?';
   if (Symflags & object::SymbolRef::SF_Absolute)
     Ret = 'a';
-  else if (IRObjectFile *IR = dyn_cast<IRObjectFile>(&Obj)) {
+  else if (IRObjectFile *IR = dyn_cast<IRObjectFile>(&Obj))
     Ret = getSymbolNMTypeChar(*IR, I);
-    Triple Host(sys::getDefaultTargetTriple());
-    if (Ret == 'd' && Host.isOSDarwin() && Symflags & SymbolRef::SF_Const)
-      Ret = 's';
-  }
   else if (COFFObjectFile *COFF = dyn_cast<COFFObjectFile>(&Obj))
     Ret = getSymbolNMTypeChar(*COFF, I);
   else if (MachOObjectFile *MachO = dyn_cast<MachOObjectFile>(&Obj))