Make the need-stub variables accurate and consistent. In the case of

MachineRelocations, "stub" always refers to a far-call stub or a
load-a-faraway-global stub, so this patch adds "Far" to the term. (Other stubs
are used for lazy compilation and dlsym address replacement.) The variable was
also inconsistent between the positive and negative sense, and the positive
sense ("NeedStub") was more demanding than is accurate (since a nearby-enough
function can be called directly even if the platform often requires a stub).
Since the negative sense causes double-negatives, I switched to
"MayNeedFarStub" globally.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86363 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 17 insertions, 15 deletions

diff --git a/include/llvm/CodeGen/MachineRelocation.h b/include/llvm/CodeGen/MachineRelocation.h
index 6ea8f076684b..1c15fab532d4 100644
--- a/include/llvm/CodeGen/MachineRelocation.h
+++ b/include/llvm/CodeGen/MachineRelocation.h
@@ -65,7 +65,7 @@ class MachineRelocation {
 
   unsigned TargetReloType : 6; // The target relocation ID
   AddressType AddrType    : 4; // The field of Target to use
-  bool NeedStub           : 1; // True if this relocation requires a stub
+  bool MayNeedFarStub     : 1; // True if this relocation may require a far-stub
   bool GOTRelative        : 1; // Should this relocation be relative to the GOT?
   bool TargetResolve      : 1; // True if target should resolve the address
 
@@ -81,7 +81,7 @@ public:
   ///
   static MachineRelocation getGV(uintptr_t offset, unsigned RelocationType, 
                                  GlobalValue *GV, intptr_t cst = 0,
-                                 bool NeedStub = 0,
+                                 bool MayNeedFarStub = 0,
                                  bool GOTrelative = 0) {
     assert((RelocationType & ~63) == 0 && "Relocation type too large!");
     MachineRelocation Result;
@@ -89,7 +89,7 @@ public:
     Result.ConstantVal = cst;
     Result.TargetReloType = RelocationType;
     Result.AddrType = isGV;
-    Result.NeedStub = NeedStub;
+    Result.MayNeedFarStub = MayNeedFarStub;
     Result.GOTRelative = GOTrelative;
     Result.TargetResolve = false;
     Result.Target.GV = GV;
@@ -101,7 +101,7 @@ public:
   static MachineRelocation getIndirectSymbol(uintptr_t offset,
                                              unsigned RelocationType, 
                                              GlobalValue *GV, intptr_t cst = 0,
-                                             bool NeedStub = 0,
+                                             bool MayNeedFarStub = 0,
                                              bool GOTrelative = 0) {
     assert((RelocationType & ~63) == 0 && "Relocation type too large!");
     MachineRelocation Result;
@@ -109,7 +109,7 @@ public:
     Result.ConstantVal = cst;
     Result.TargetReloType = RelocationType;
     Result.AddrType = isIndirectSym;
-    Result.NeedStub = NeedStub;
+    Result.MayNeedFarStub = MayNeedFarStub;
     Result.GOTRelative = GOTrelative;
     Result.TargetResolve = false;
     Result.Target.GV = GV;
@@ -126,7 +126,7 @@ public:
     Result.ConstantVal = cst;
     Result.TargetReloType = RelocationType;
     Result.AddrType = isBB;
-    Result.NeedStub = false;
+    Result.MayNeedFarStub = false;
     Result.GOTRelative = false;
     Result.TargetResolve = false;
     Result.Target.MBB = MBB;
@@ -145,7 +145,7 @@ public:
     Result.ConstantVal = cst;
     Result.TargetReloType = RelocationType;
     Result.AddrType = isExtSym;
-    Result.NeedStub = true;
+    Result.MayNeedFarStub = true;
     Result.GOTRelative = GOTrelative;
     Result.TargetResolve = false;
     Result.Target.ExtSym = ES;
@@ -164,7 +164,7 @@ public:
     Result.ConstantVal = cst;
     Result.TargetReloType = RelocationType;
     Result.AddrType = isConstPool;
-    Result.NeedStub = false;
+    Result.MayNeedFarStub = false;
     Result.GOTRelative = false;
     Result.TargetResolve = letTargetResolve;
     Result.Target.Index = CPI;
@@ -183,7 +183,7 @@ public:
     Result.ConstantVal = cst;
     Result.TargetReloType = RelocationType;
     Result.AddrType = isJumpTable;
-    Result.NeedStub = false;
+    Result.MayNeedFarStub = false;
     Result.GOTRelative = false;
     Result.TargetResolve = letTargetResolve;
     Result.Target.Index = JTI;
@@ -258,12 +258,14 @@ public:
     return GOTRelative;
   }
 
-  /// doesntNeedStub - This function returns true if the JIT for this target
-  /// target is capable of directly handling the relocated GlobalValue reference
-  /// without using either a stub function or issuing an extra load to get the
-  /// GV address.
-  bool doesntNeedStub() const {
-    return !NeedStub;
+  /// mayNeedFarStub - This function returns true if the JIT for this target may
+  /// need either a stub function or an indirect global-variable load to handle
+  /// the relocated GlobalValue reference.  For example, the x86-64 call
+  /// instruction can only call functions within +/-2GB of the call site.
+  /// Anything farther away needs a longer mov+call sequence, which can't just
+  /// be written on top of the existing call.
+  bool mayNeedFarStub() const {
+    return MayNeedFarStub;
   }
 
   /// letTargetResolve - Return true if the target JITInfo is usually