From beb9d409006abd85ab7a9c1632fdb1d6ad9e6cdd Mon Sep 17 00:00:00 2001
From: Anton Korobeynikov <asl@math.spbu.ru>
Date: Wed, 9 Jul 2008 13:16:59 +0000
Subject: [PATCH] Add code for default section falgs computation

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53290 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Target/TargetAsmInfo.h | 27 +++++++++++++
 lib/Target/TargetAsmInfo.cpp        | 63 +++++++++++++++++++++++++++++
 2 files changed, 90 insertions(+)

diff --git a/include/llvm/Target/TargetAsmInfo.h b/include/llvm/Target/TargetAsmInfo.h
index bf4fd103383..65c0df49812 100644
--- a/include/llvm/Target/TargetAsmInfo.h
+++ b/include/llvm/Target/TargetAsmInfo.h
@@ -30,6 +30,7 @@ namespace llvm {
 
   namespace SectionKind {
     enum Kind {
+      Unknown = 0,      ///< Custom section
       Text,             ///< Text section
       Data,             ///< Data section
       BSS,              ///< BSS section
@@ -41,6 +42,25 @@ namespace llvm {
     };
   }
 
+  namespace SectionFlags {
+    enum Flags {
+      None       = 0,
+      Code       = 1 << 0, ///< Section contains code
+      Writeable  = 1 << 1, ///< Section is writeable
+      BSS        = 1 << 2, ///< Section contains only zeroes
+      Mergeable  = 1 << 3, ///< Section contains mergeable data
+      Strings    = 1 << 4, ///< Section contains null-terminated strings
+      TLS        = 1 << 5, ///< Section contains thread-local data
+      Debug      = 1 << 6, ///< Section contains debug data
+      Linkonce   = 1 << 7  ///< Section is linkonce
+    };
+  }
+
+  struct SectionInfo {
+    SectionKind::Kind   kind;
+    SectionFlags::Flags flags;
+  };
+
   class TargetMachine;
   class CallInst;
   class GlobalValue;
@@ -444,6 +464,13 @@ namespace llvm {
     /// section kind used for global emission.
     SectionKind::Kind SectionKindForGlobal(const GlobalValue *GV) const;
 
+
+    /// SectionFlagsForGlobal - This hook allows the target to select proper
+    /// section flags either for given global or for section.
+    unsigned
+    SectionFlagsForGlobal(const GlobalValue *GV = NULL,
+                          const char* name = NULL);
+
     // Accessors.
     //
     const char *getTextSection() const {
diff --git a/lib/Target/TargetAsmInfo.cpp b/lib/Target/TargetAsmInfo.cpp
index 2adad3d7baa..cda939c87cf 100644
--- a/lib/Target/TargetAsmInfo.cpp
+++ b/lib/Target/TargetAsmInfo.cpp
@@ -191,3 +191,66 @@ TargetAsmInfo::SectionKindForGlobal(const GlobalValue *GV) const {
   // Variable is not constant or thread-local - emit to generic data section.
   return (isThreadLocal ? SectionKind::ThreadData : SectionKind::Data);
 }
+
+unsigned
+TargetAsmInfo::SectionFlagsForGlobal(const GlobalValue *GV,
+                                     const char* name) {
+  unsigned flags = SectionFlags::None;
+
+  // Decode flags from global itself.
+  if (GV) {
+    SectionKind::Kind kind = SectionKindForGlobal(GV);
+    switch (kind) {
+     case SectionKind::Text:
+      flags |= SectionFlags::Code;
+      break;
+     case SectionKind::ThreadData:
+      flags |= SectionFlags::TLS;
+      // FALLS THROUGH
+     case SectionKind::Data:
+      flags |= SectionFlags::Writeable;
+      break;
+     case SectionKind::ThreadBSS:
+      flags |= SectionFlags::TLS;
+      // FALLS THROUGH
+     case SectionKind::BSS:
+      flags |= SectionFlags::BSS;
+      break;
+     case SectionKind::ROData:
+      // No additional flags here
+      break;
+     case SectionKind::RODataMergeStr:
+      flags |= SectionFlags::Strings;
+      // FALLS THROUGH
+     case SectionKind::RODataMergeConst:
+      flags |= SectionFlags::Mergeable;
+      break;
+     default:
+      assert(0 && "Unexpected section kind!");
+    }
+
+    if (GV->hasLinkOnceLinkage() ||
+        GV->hasWeakLinkage() ||
+        GV->hasCommonLinkage())
+      flags |= SectionFlags::Linkonce;
+  }
+
+  // Add flags from sections, if any.
+  if (name) {
+    // Some lame default implementation
+    if (strcmp(name, ".bss") == 0 ||
+        strncmp(name, ".bss.", 5) == 0 ||
+        strncmp(name, ".gnu.linkonce.b.", 16) == 0)
+      flags |= SectionFlags::BSS;
+    else if (strcmp(name, ".tdata") == 0 ||
+             strncmp(name, ".tdata.", 7) == 0 ||
+             strncmp(name, ".gnu.linkonce.td.", 17) == 0)
+      flags |= SectionFlags::TLS;
+    else if (strcmp(name, ".tbss") == 0 ||
+             strncmp(name, ".tbss.", 6) == 0 ||
+             strncmp(name, ".gnu.linkonce.tb.", 17) == 0)
+      flags |= SectionFlags::BSS | SectionFlags::TLS;
+  }
+
+  return flags;
+}