1 //===-- MachineCodeForMethod.cpp -------------------------------------------=//
2 //
3 // Purpose:
4 //   Collect native machine code information for a function.
5 //   This allows target-specific information about the generated code
6 //   to be stored with each function.
7 //===---------------------------------------------------------------------===//
8 
9 #include "llvm/CodeGen/MachineCodeForMethod.h"
10 #include "llvm/CodeGen/MachineInstr.h"  // For debug output
11 #include "llvm/CodeGen/MachineCodeForBasicBlock.h"
12 #include "llvm/Target/TargetMachine.h"
13 #include "llvm/Target/MachineFrameInfo.h"
14 #include "llvm/Target/MachineCacheInfo.h"
15 #include "llvm/Function.h"
16 #include "llvm/BasicBlock.h"
17 #include "llvm/iOther.h"
18 #include <limits.h>
19 #include <iostream>
20 
21 const int INVALID_FRAME_OFFSET = INT_MAX; // std::numeric_limits<int>::max();
22 
23 static AnnotationID MCFM_AID(
24                  AnnotationManager::getID("CodeGen::MachineCodeForFunction"));
25 
26 // The next two methods are used to construct and to retrieve
27 // the MachineCodeForFunction object for the given function.
28 // construct() -- Allocates and initializes for a given function and target
29 // get()       -- Returns a handle to the object.
30 //                This should not be called before "construct()"
31 //                for a given Function.
32 //
33 MachineCodeForMethod&
34 MachineCodeForMethod::construct(const Function *M, const TargetMachine &Tar)
35 {
36   assert(M->getAnnotation(MCFM_AID) == 0 &&
37          "Object already exists for this function!");
38   MachineCodeForMethod* mcInfo = new MachineCodeForMethod(M, Tar);
39   M->addAnnotation(mcInfo);
40   return *mcInfo;
41 }
42 
43 void
44 MachineCodeForMethod::destruct(const Function *M)
45 {
46   bool Deleted = M->deleteAnnotation(MCFM_AID);
47   assert(Deleted && "Machine code did not exist for function!");
48 }
49 
50 MachineCodeForMethod&
51 MachineCodeForMethod::get(const Function *F)
52 {
53   MachineCodeForMethod *mc = (MachineCodeForMethod*)F->getAnnotation(MCFM_AID);
54   assert(mc && "Call construct() method first to allocate the object");
55   return *mc;
56 }
57 
58 static unsigned
59 ComputeMaxOptionalArgsSize(const TargetMachine& target, const Function *F,
60                            unsigned &maxOptionalNumArgs)
61 {
62   const MachineFrameInfo& frameInfo = target.getFrameInfo();
63 
64   unsigned maxSize = 0;
65 
66   for (Function::const_iterator BB = F->begin(), BBE = F->end(); BB !=BBE; ++BB)
67     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I)
68       if (const CallInst *callInst = dyn_cast<CallInst>(&*I))
69         {
70           unsigned numOperands = callInst->getNumOperands() - 1;
71           int numExtra = (int)numOperands-frameInfo.getNumFixedOutgoingArgs();
72           if (numExtra <= 0)
73             continue;
74 
75           unsigned int sizeForThisCall;
76           if (frameInfo.argsOnStackHaveFixedSize())
77             {
78               int argSize = frameInfo.getSizeOfEachArgOnStack();
79               sizeForThisCall = numExtra * (unsigned) argSize;
80             }
81           else
82             {
83               assert(0 && "UNTESTED CODE: Size per stack argument is not "
84                      "fixed on this architecture: use actual arg sizes to "
85                      "compute MaxOptionalArgsSize");
86               sizeForThisCall = 0;
87               for (unsigned i = 0; i < numOperands; ++i)
88                 sizeForThisCall += target.findOptimalStorageSize(callInst->
89                                               getOperand(i)->getType());
90             }
91 
92           if (maxSize < sizeForThisCall)
93             maxSize = sizeForThisCall;
94 
95           if ((int)maxOptionalNumArgs < numExtra)
96             maxOptionalNumArgs = (unsigned) numExtra;
97         }
98 
99   return maxSize;
100 }
101 
102 // Align data larger than one L1 cache line on L1 cache line boundaries.
103 // Align all smaller data on the next higher 2^x boundary (4, 8, ...).
104 //
105 // THIS FUNCTION HAS BEEN COPIED FROM EMITASSEMBLY.CPP AND
106 // SHOULD BE USED DIRECTLY THERE
107 //
108 inline unsigned int
109 SizeToAlignment(unsigned int size, const TargetMachine& target)
110 {
111   unsigned short cacheLineSize = target.getCacheInfo().getCacheLineSize(1);
112   if (size > (unsigned) cacheLineSize / 2)
113     return cacheLineSize;
114   else
115     for (unsigned sz=1; /*no condition*/; sz *= 2)
116       if (sz >= size)
117         return sz;
118 }
119 
120 
121 
122 /*ctor*/
123 MachineCodeForMethod::MachineCodeForMethod(const Function *F,
124                                            const TargetMachine& target)
125   : Annotation(MCFM_AID),
126     method(F), staticStackSize(0),
127     automaticVarsSize(0), regSpillsSize(0),
128     maxOptionalArgsSize(0), maxOptionalNumArgs(0),
129     currentTmpValuesSize(0), maxTmpValuesSize(0), compiledAsLeaf(false),
130     spillsAreaFrozen(false), automaticVarsAreaFrozen(false)
131 {
132   maxOptionalArgsSize = ComputeMaxOptionalArgsSize(target, method,
133                                                    maxOptionalNumArgs);
134   staticStackSize = maxOptionalArgsSize
135                     + target.getFrameInfo().getMinStackFrameSize();
136 }
137 
138 int
139 MachineCodeForMethod::computeOffsetforLocalVar(const TargetMachine& target,
140                                                const Value* val,
141                                                unsigned int& getPaddedSize,
142                                                unsigned int  sizeToUse = 0)
143 {
144   bool growUp;
145   int firstOffset =target.getFrameInfo().getFirstAutomaticVarOffset(*this,
146                                                                     growUp);
147   unsigned char align;
148   if (sizeToUse == 0)
149     {
150       sizeToUse = target.findOptimalStorageSize(val->getType());
151       // align = target.DataLayout.getTypeAlignment(val->getType());
152     }
153 
154   align = SizeToAlignment(sizeToUse, target);
155 
156   int offset = getAutomaticVarsSize();
157   if (! growUp)
158     offset += sizeToUse;
159 
160   if (unsigned int mod = offset % align)
161     {
162       offset        += align - mod;
163       getPaddedSize  = sizeToUse + align - mod;
164     }
165   else
166     getPaddedSize  = sizeToUse;
167 
168   offset = growUp? firstOffset + offset
169     : firstOffset - offset;
170 
171   return offset;
172 }
173 
174 int
175 MachineCodeForMethod::allocateLocalVar(const TargetMachine& target,
176                                        const Value* val,
177                                        unsigned int sizeToUse = 0)
178 {
179   assert(! automaticVarsAreaFrozen &&
180          "Size of auto vars area has been used to compute an offset so "
181          "no more automatic vars should be allocated!");
182 
183   // Check if we've allocated a stack slot for this value already
184   //
185   int offset = getOffset(val);
186   if (offset == INVALID_FRAME_OFFSET)
187     {
188       unsigned int getPaddedSize;
189       offset = this->computeOffsetforLocalVar(target, val, getPaddedSize,
190                                               sizeToUse);
191       offsets[val] = offset;
192       incrementAutomaticVarsSize(getPaddedSize);
193     }
194   return offset;
195 }
196 
197 int
198 MachineCodeForMethod::allocateSpilledValue(const TargetMachine& target,
199                                            const Type* type)
200 {
201   assert(! spillsAreaFrozen &&
202          "Size of reg spills area has been used to compute an offset so "
203          "no more register spill slots should be allocated!");
204 
205   unsigned int size  = target.findOptimalStorageSize(type);
206   unsigned char align = target.DataLayout.getTypeAlignment(type);
207 
208   bool growUp;
209   int firstOffset = target.getFrameInfo().getRegSpillAreaOffset(*this, growUp);
210 
211   int offset = getRegSpillsSize();
212   if (! growUp)
213     offset += size;
214 
215   if (unsigned int mod = offset % align)
216     {
217       offset    += align - mod;
218       size += align - mod;
219     }
220 
221   offset = growUp? firstOffset + offset
222                  : firstOffset - offset;
223 
224   incrementRegSpillsSize(size);
225 
226   return offset;
227 }
228 
229 int
230 MachineCodeForMethod::pushTempValue(const TargetMachine& target,
231                                     unsigned int size)
232 {
233   // Compute a power-of-2 alignment according to the possible sizes,
234   // but not greater than the alignment of the largest type we support
235   // (currently a double word -- see class TargetData).
236   unsigned char align = 1;
237   for (; align < size && align < target.DataLayout.getDoubleAlignment();
238          align = 2*align)
239     ;
240 
241   bool growUp;
242   int firstTmpOffset = target.getFrameInfo().getTmpAreaOffset(*this, growUp);
243 
244   int offset = currentTmpValuesSize;
245   if (! growUp)
246     offset += size;
247 
248   if (unsigned int mod = offset % align)
249     {
250       offset += align - mod;
251       size   += align - mod;
252     }
253 
254   offset = growUp ? firstTmpOffset + offset : firstTmpOffset - offset;
255 
256   incrementTmpAreaSize(size);
257   return offset;
258 }
259 
260 void
261 MachineCodeForMethod::popAllTempValues(const TargetMachine& target)
262 {
263   resetTmpAreaSize();
264 }
265 
266 int
267 MachineCodeForMethod::getOffset(const Value* val) const
268 {
269   hash_map<const Value*, int>::const_iterator pair = offsets.find(val);
270   return (pair == offsets.end())? INVALID_FRAME_OFFSET : pair->second;
271 }
272 
273 void
274 MachineCodeForMethod::dump() const
275 {
276   std::cerr << "\n" << method->getReturnType()
277             << " \"" << method->getName() << "\"\n";
278 
279   for (Function::const_iterator BB = method->begin(); BB != method->end(); ++BB)
280     {
281       std::cerr << std::endl << (*BB).getName() << " (" << (const void*) BB << ")" << ":" << std::endl;
282       MachineCodeForBasicBlock& mvec = MachineCodeForBasicBlock::get(BB);
283       for (unsigned i=0; i < mvec.size(); i++)
284 	std::cerr << "\t" << *mvec[i];
285     }
286   std::cerr << "\nEnd function \"" << method->getName() << "\"\n\n";
287 }
288