brg

InstSelectSimple.cpp: Add stub implementation of visitFreeInst.
 Add comments that mention how we are failing to implement malloc/free.
 Add initial implementation of visitAllocaInst.

X86TargetMachine.cpp: Include llvm/Transforms/Scalar.h.
 Add LowerAllocations pass before instruction selection.

jello/Makefile: Add scalaropts.a.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4994 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/X86/InstSelectSimple.cpp

@@ -101,6 +101,7 @@ namespace {
     void visitStoreInst(StoreInst &I);
     void visitGetElementPtrInst(GetElementPtrInst &I);
     void visitMallocInst(MallocInst &I);
+    void visitFreeInst(FreeInst &I);
     void visitAllocaInst(AllocaInst &I);
     
     // Other operators
@@ -885,6 +886,20 @@ ISel::visitGetElementPtrInst (GetElementPtrInst &I)
 void
 ISel::visitMallocInst (MallocInst &I)
 {
+  // We assume that by this point, malloc instructions have been
+  // lowered to calls, and dlsym will magically find malloc for us.
+  // So we do not want to see malloc instructions here.
+  visitInstruction (I);
+}
+
+
+/// visitFreeInst - same story as MallocInst
+void
+ISel::visitFreeInst (FreeInst &I)
+{
+  // We assume that by this point, free instructions have been
+  // lowered to calls, and dlsym will magically find free for us.
+  // So we do not want to see free instructions here.
   visitInstruction (I);
 }
 
@@ -894,7 +909,18 @@ ISel::visitMallocInst (MallocInst &I)
 void
 ISel::visitAllocaInst (AllocaInst &I)
 {
-  visitInstruction (I);
+  // Find the data size of the alloca inst's getAllocatedType.
+  const Type *allocatedType = I.getAllocatedType ();
+  const TargetData &TD = TM.DataLayout;
+  unsigned allocatedTypeSize = TD.getTypeSize (allocatedType);
+  // Keep stack 32-bit aligned.
+  unsigned int allocatedTypeWords = allocatedTypeSize / 4;
+  if (allocatedTypeSize % 4 != 0) { allocatedTypeWords++; }
+  // Subtract size from stack pointer, thereby allocating some space.
+  BuildMI (BB, X86::SUBri32, 1, X86::ESP).addZImm (allocatedTypeWords * 4);
+  // Put a pointer to the space into the result register, by copying
+  // the stack pointer.
+  BuildMI (BB, X86::MOVrr32, 1, getReg (I)).addReg (X86::ESP);
 }
     
 

lib/Target/X86/X86ISelSimple.cpp

@@ -101,6 +101,7 @@ namespace {
     void visitStoreInst(StoreInst &I);
     void visitGetElementPtrInst(GetElementPtrInst &I);
     void visitMallocInst(MallocInst &I);
+    void visitFreeInst(FreeInst &I);
     void visitAllocaInst(AllocaInst &I);
     
     // Other operators
@@ -885,6 +886,20 @@ ISel::visitGetElementPtrInst (GetElementPtrInst &I)
 void
 ISel::visitMallocInst (MallocInst &I)
 {
+  // We assume that by this point, malloc instructions have been
+  // lowered to calls, and dlsym will magically find malloc for us.
+  // So we do not want to see malloc instructions here.
+  visitInstruction (I);
+}
+
+
+/// visitFreeInst - same story as MallocInst
+void
+ISel::visitFreeInst (FreeInst &I)
+{
+  // We assume that by this point, free instructions have been
+  // lowered to calls, and dlsym will magically find free for us.
+  // So we do not want to see free instructions here.
   visitInstruction (I);
 }
 
@@ -894,7 +909,18 @@ ISel::visitMallocInst (MallocInst &I)
 void
 ISel::visitAllocaInst (AllocaInst &I)
 {
-  visitInstruction (I);
+  // Find the data size of the alloca inst's getAllocatedType.
+  const Type *allocatedType = I.getAllocatedType ();
+  const TargetData &TD = TM.DataLayout;
+  unsigned allocatedTypeSize = TD.getTypeSize (allocatedType);
+  // Keep stack 32-bit aligned.
+  unsigned int allocatedTypeWords = allocatedTypeSize / 4;
+  if (allocatedTypeSize % 4 != 0) { allocatedTypeWords++; }
+  // Subtract size from stack pointer, thereby allocating some space.
+  BuildMI (BB, X86::SUBri32, 1, X86::ESP).addZImm (allocatedTypeWords * 4);
+  // Put a pointer to the space into the result register, by copying
+  // the stack pointer.
+  BuildMI (BB, X86::MOVrr32, 1, getReg (I)).addReg (X86::ESP);
 }
     
 

lib/Target/X86/X86TargetMachine.cpp

@@ -5,6 +5,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "X86TargetMachine.h"
+#include "llvm/Transforms/Scalar.h"
 #include "llvm/Target/TargetMachineImpls.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/PassManager.h"
@@ -28,6 +29,11 @@ X86TargetMachine::X86TargetMachine() : TargetMachine("X86", 1, 4, 4, 4) {
 /// not supported for this target.
 ///
 bool X86TargetMachine::addPassesToJITCompile(PassManager &PM) {
+  // For the moment we have decided that malloc and free will be
+  // taken care of by converting them to calls, using the existing
+  // LLVM scalar transforms pass to do this.
+  PM.add(createLowerAllocationsPass());
+
   PM.add(createSimpleX86InstructionSelector(*this));
 
   // TODO: optional optimizations go here

tools/jello/Makefile

@@ -1,6 +1,6 @@
 LEVEL = ../..
 TOOLNAME = jello
-USEDLIBS = bcreader vmcore codegen x86 support.a target.a
+USEDLIBS = bcreader vmcore codegen x86 support.a target.a scalaropts.a
 
 # Have gcc tell the linker to export symbols from the program so that
 # dynamically loaded modules can be linked against them.