1 //===- lib/MC/MCWin64EH.cpp - MCWin64EH implementation --------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/MC/MCWin64EH.h"
11 #include "llvm/MC/MCStreamer.h"
12 #include "llvm/MC/MCContext.h"
13 #include "llvm/MC/MCExpr.h"
14 #include "llvm/Target/TargetAsmInfo.h"
18 // NOTE: All relocations generated here are 4-byte image-relative.
20 static uint8_t CountOfUnwindCodes(std::vector<MCWin64EHInstruction> &instArray){
22 for (std::vector<MCWin64EHInstruction>::const_iterator I = instArray.begin(),
23 E = instArray.end(); I != E; ++I) {
24 switch (I->getOperation()) {
25 case Win64EH::UOP_PushNonVol:
26 case Win64EH::UOP_AllocSmall:
27 case Win64EH::UOP_SetFPReg:
28 case Win64EH::UOP_PushMachFrame:
31 case Win64EH::UOP_SaveNonVol:
32 case Win64EH::UOP_SaveXMM128:
35 case Win64EH::UOP_SaveNonVolBig:
36 case Win64EH::UOP_SaveXMM128Big:
39 case Win64EH::UOP_AllocLarge:
40 if (I->getSize() > 512*1024-8)
50 static void EmitAbsDifference(MCStreamer &streamer, MCSymbol *lhs,
52 MCContext &context = streamer.getContext();
53 const MCExpr *diff = MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(
55 MCSymbolRefExpr::Create(
58 streamer.EmitAbsValue(diff, 1);
62 static void EmitUnwindCode(MCStreamer &streamer, MCSymbol *begin,
63 MCWin64EHInstruction &inst) {
66 b2 = (inst.getOperation() & 0x0F);
67 switch (inst.getOperation()) {
68 case Win64EH::UOP_PushNonVol:
69 EmitAbsDifference(streamer, inst.getLabel(), begin);
70 b2 |= (inst.getRegister() & 0x0F) << 4;
71 streamer.EmitIntValue(b2, 1);
73 case Win64EH::UOP_AllocLarge:
74 EmitAbsDifference(streamer, inst.getLabel(), begin);
75 if (inst.getSize() > 512*1024-8) {
77 streamer.EmitIntValue(b2, 1);
78 w = inst.getSize() & 0xFFF8;
79 streamer.EmitIntValue(w, 2);
80 w = inst.getSize() >> 16;
82 streamer.EmitIntValue(b2, 1);
83 w = inst.getSize() >> 3;
85 streamer.EmitIntValue(w, 2);
87 case Win64EH::UOP_AllocSmall:
88 b2 |= (((inst.getSize()-8) >> 3) & 0x0F) << 4;
89 EmitAbsDifference(streamer, inst.getLabel(), begin);
90 streamer.EmitIntValue(b2, 1);
92 case Win64EH::UOP_SetFPReg:
93 b1 = inst.getOffset() & 0xF0;
94 streamer.EmitIntValue(b1, 1);
95 streamer.EmitIntValue(b2, 1);
97 case Win64EH::UOP_SaveNonVol:
98 case Win64EH::UOP_SaveXMM128:
99 b2 |= (inst.getRegister() & 0x0F) << 4;
100 EmitAbsDifference(streamer, inst.getLabel(), begin);
101 streamer.EmitIntValue(b2, 1);
102 w = inst.getOffset() >> 3;
103 if (inst.getOperation() == Win64EH::UOP_SaveXMM128)
105 streamer.EmitIntValue(w, 2);
107 case Win64EH::UOP_SaveNonVolBig:
108 case Win64EH::UOP_SaveXMM128Big:
109 b2 |= (inst.getRegister() & 0x0F) << 4;
110 EmitAbsDifference(streamer, inst.getLabel(), begin);
111 streamer.EmitIntValue(b2, 1);
112 if (inst.getOperation() == Win64EH::UOP_SaveXMM128Big)
113 w = inst.getOffset() & 0xFFF0;
115 w = inst.getOffset() & 0xFFF8;
116 streamer.EmitIntValue(w, 2);
117 w = inst.getOffset() >> 16;
118 streamer.EmitIntValue(w, 2);
120 case Win64EH::UOP_PushMachFrame:
121 if (inst.isPushCodeFrame())
123 EmitAbsDifference(streamer, inst.getLabel(), begin);
124 streamer.EmitIntValue(b2, 1);
129 static void EmitRuntimeFunction(MCStreamer &streamer,
130 const MCWin64EHUnwindInfo *info) {
131 MCContext &context = streamer.getContext();
133 streamer.EmitValueToAlignment(4);
134 streamer.EmitValue(MCSymbolRefExpr::Create(info->Begin, context), 4);
135 streamer.EmitValue(MCSymbolRefExpr::Create(info->End, context), 4);
136 streamer.EmitValue(MCSymbolRefExpr::Create(info->Symbol, context), 4);
139 static void EmitUnwindInfo(MCStreamer &streamer, MCWin64EHUnwindInfo *info) {
140 // If this UNWIND_INFO already has a symbol, it's already been emitted.
141 if (info->Symbol) return;
143 MCContext &context = streamer.getContext();
144 streamer.EmitValueToAlignment(4);
145 // Upper 3 bits are the version number (currently 1).
146 uint8_t flags = 0x01;
147 info->Symbol = context.CreateTempSymbol();
148 streamer.EmitLabel(info->Symbol);
150 if (info->ChainedParent)
151 flags |= Win64EH::UNW_ChainInfo << 3;
153 if (info->HandlesUnwind)
154 flags |= Win64EH::UNW_TerminateHandler << 3;
155 if (info->HandlesExceptions)
156 flags |= Win64EH::UNW_ExceptionHandler << 3;
158 streamer.EmitIntValue(flags, 1);
161 EmitAbsDifference(streamer, info->PrologEnd, info->Begin);
163 streamer.EmitIntValue(0, 1);
165 uint8_t numCodes = CountOfUnwindCodes(info->Instructions);
166 streamer.EmitIntValue(numCodes, 1);
169 if (info->LastFrameInst >= 0) {
170 MCWin64EHInstruction &frameInst = info->Instructions[info->LastFrameInst];
171 assert(frameInst.getOperation() == Win64EH::UOP_SetFPReg);
172 frame = (frameInst.getRegister() & 0x0F) |
173 (frameInst.getOffset() & 0xF0);
175 streamer.EmitIntValue(frame, 1);
177 // Emit unwind instructions (in reverse order).
178 uint8_t numInst = info->Instructions.size();
179 for (uint8_t c = 0; c < numInst; ++c) {
180 MCWin64EHInstruction inst = info->Instructions.back();
181 info->Instructions.pop_back();
182 EmitUnwindCode(streamer, info->Begin, inst);
185 if (flags & (Win64EH::UNW_ChainInfo << 3))
186 EmitRuntimeFunction(streamer, info->ChainedParent);
188 ((Win64EH::UNW_TerminateHandler|Win64EH::UNW_ExceptionHandler) << 3))
189 streamer.EmitValue(MCSymbolRefExpr::Create(info->ExceptionHandler, context),
191 else if (numCodes < 2) {
192 // The minimum size of an UNWIND_INFO struct is 8 bytes. If we're not
193 // a chained unwind info, if there is no handler, and if there are fewer
194 // than 2 slots used in the unwind code array, we have to pad to 8 bytes.
196 streamer.EmitIntValue(0, 2);
198 streamer.EmitIntValue(0, 4);
202 void MCWin64EHUnwindEmitter::EmitUnwindInfo(MCStreamer &streamer,
203 MCWin64EHUnwindInfo *info) {
204 // Switch sections (the static function above is meant to be called from
205 // here and from Emit().
206 MCContext &context = streamer.getContext();
207 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
208 const MCSection *xdataSect = asmInfo.getWin64EHTableSection();
209 streamer.SwitchSection(xdataSect);
211 llvm::EmitUnwindInfo(streamer, info);
214 void MCWin64EHUnwindEmitter::Emit(MCStreamer &streamer) {
215 MCContext &context = streamer.getContext();
216 // Emit the unwind info structs first.
217 const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
218 const MCSection *xdataSect = asmInfo.getWin64EHTableSection();
219 streamer.SwitchSection(xdataSect);
220 for (unsigned i = 0; i < streamer.getNumW64UnwindInfos(); ++i)
221 llvm::EmitUnwindInfo(streamer, &streamer.getW64UnwindInfo(i));
222 // Now emit RUNTIME_FUNCTION entries.
223 const MCSection *pdataSect = asmInfo.getWin64EHFuncTableSection();
224 streamer.SwitchSection(pdataSect);
225 for (unsigned i = 0; i < streamer.getNumW64UnwindInfos(); ++i)
226 EmitRuntimeFunction(streamer, &streamer.getW64UnwindInfo(i));
229 } // End of namespace llvm