From 76dbbd6e2451b04fed04a826b48d5f1b54d4feea Mon Sep 17 00:00:00 2001
From: Anton Korobeynikov <asl@math.spbu.ru>
Date: Wed, 20 Dec 2006 01:03:20 +0000
Subject: [PATCH] Fixed dllimported symbols support during JIT'ing. JIT on
 mingw32 platform should be more or less workable. At least, sim is running
 fine under lli :)

llvm-svn: 32711
---
 lib/Target/X86/X86Subtarget.cpp     | 25 ++++++++++++++++++-------
 lib/Target/X86/X86Subtarget.h       |  7 +++++++
 lib/Target/X86/X86TargetMachine.cpp |  3 +++
 3 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/lib/Target/X86/X86Subtarget.cpp b/lib/Target/X86/X86Subtarget.cpp
index ff88fdbca26..5281dcda7aa 100644
--- a/lib/Target/X86/X86Subtarget.cpp
+++ b/lib/Target/X86/X86Subtarget.cpp
@@ -32,13 +32,14 @@ AsmWriterFlavor("x86-asm-syntax", cl::init(X86Subtarget::unset),
 /// or index register of the address, not the GV offset field.
 bool X86Subtarget::GVRequiresExtraLoad(const GlobalValue* GV, bool isDirectCall) const
 {
-  if (isTargetDarwin()) {
-    return (!isDirectCall &&
-            (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
-             (GV->isExternal() && !GV->hasNotBeenReadFromBytecode())));
-  } else if (isTargetCygwin() || isTargetWindows()) {
-    return (GV->hasDLLImportLinkage());
-  }
+  if (GenerateExtraLoadsForGVs)
+    if (isTargetDarwin()) {
+      return (!isDirectCall &&
+              (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
+               (GV->isExternal() && !GV->hasNotBeenReadFromBytecode())));
+    } else if (isTargetCygwin() || isTargetWindows()) {
+      return (GV->hasDLLImportLinkage());
+    }
   
   return false;
 }
@@ -206,6 +207,15 @@ static const char *GetCurrentX86CPU() {
   }
 }
 
+/// SetJITMode - This is called to inform the subtarget info that we are
+/// producing code for the JIT.
+void X86Subtarget::SetJITMode() {
+  // JIT mode doesn't want extra loads for dllimported symbols, it knows exactly
+  // where everything is.
+  if (isTargetCygwin())
+    GenerateExtraLoadsForGVs = false;
+}
+
 X86Subtarget::X86Subtarget(const Module &M, const std::string &FS, bool is64Bit)
   : AsmFlavor(AsmWriterFlavor)
   , X86SSELevel(NoMMXSSE)
@@ -214,6 +224,7 @@ X86Subtarget::X86Subtarget(const Module &M, const std::string &FS, bool is64Bit)
   // FIXME: this is a known good value for Yonah. How about others?
   , MinRepStrSizeThreshold(128)
   , Is64Bit(is64Bit)
+  , GenerateExtraLoadsForGVs(true)
   , TargetType(isELF) { // Default to ELF unless otherwise specified.
 
   // Determine default and user specified characteristics
diff --git a/lib/Target/X86/X86Subtarget.h b/lib/Target/X86/X86Subtarget.h
index 70e70e90110..4a3bc342ee2 100644
--- a/lib/Target/X86/X86Subtarget.h
+++ b/lib/Target/X86/X86Subtarget.h
@@ -61,6 +61,9 @@ private:
   /// pointer size is 64 bit.
   bool Is64Bit;
 
+  /// GenerateExtraLoadsForGVs - True if we should generate extra loads for
+  /// indirect symbols (e.g. dllimported symbols on windows).
+  bool GenerateExtraLoadsForGVs;
 public:
   enum {
     isELF, isCygwin, isDarwin, isWindows
@@ -112,6 +115,10 @@ public:
   /// value of GV itself. This means that the GlobalAddress must be in the base
   /// or index register of the address, not the GV offset field.
   bool GVRequiresExtraLoad(const GlobalValue* GV, bool isDirectCall) const;
+
+  /// SetJITMode - This is called to inform the subtarget info that we are
+  /// producing code for the JIT.
+  void SetJITMode();
 };
 
 namespace X86 {
diff --git a/lib/Target/X86/X86TargetMachine.cpp b/lib/Target/X86/X86TargetMachine.cpp
index 2d48056caa9..ad0bf5510c1 100644
--- a/lib/Target/X86/X86TargetMachine.cpp
+++ b/lib/Target/X86/X86TargetMachine.cpp
@@ -166,6 +166,9 @@ bool X86TargetMachine::addCodeEmitter(FunctionPassManager &PM, bool Fast,
   // JIT cannot ensure globals are placed in the lower 4G of address.
   if (Subtarget.is64Bit())
     setCodeModel(CodeModel::Large);
+
+  // Inform the subtarget that we are in JIT mode.
+  Subtarget.SetJITMode(); 
   
   PM.add(createX86CodeEmitterPass(*this, MCE));
   return false;