Iasm and obj lowering for advanced switch lowering.
Jump table emission is delayed until offsets are known. X86 local jumps can be
near or far. Sanboxing is applied to indirect jumps from jump table.
BUG=
R=stichnot@chromium.org, jvoung
Review URL: https://codereview.chromium.org/1257283004.
diff --git a/src/IceTargetLoweringX8632.cpp b/src/IceTargetLoweringX8632.cpp
index dfa042a..e8e89dd 100644
--- a/src/IceTargetLoweringX8632.cpp
+++ b/src/IceTargetLoweringX8632.cpp
@@ -151,6 +151,23 @@
const char *PoolTypeConverter<uint8_t>::PrintfString = "0x%x";
} // end of anonymous namespace
+void TargetX8632::emitJumpTable(const Cfg *Func,
+ const InstJumpTable *JumpTable) const {
+ if (!BuildDefs::dump())
+ return;
+ Ostream &Str = Ctx->getStrEmit();
+ IceString MangledName = Ctx->mangleName(Func->getFunctionName());
+ Str << "\t.section\t.rodata." << MangledName
+ << "$jumptable,\"a\",@progbits\n";
+ Str << "\t.align\t" << typeWidthInBytes(getPointerType()) << "\n";
+ Str << InstJumpTable::makeName(MangledName, JumpTable->getId()) << ":";
+
+ // On X8632 pointers are 32-bit hence the use of .long
+ for (SizeT I = 0; I < JumpTable->getNumTargets(); ++I)
+ Str << "\n\t.long\t" << JumpTable->getTarget(I)->getAsmName();
+ Str << "\n";
+}
+
template <typename T>
void TargetDataX8632::emitConstantPool(GlobalContext *Ctx) {
if (!BuildDefs::dump())
@@ -222,6 +239,35 @@
}
}
+void TargetDataX8632::lowerJumpTables() {
+ switch (Ctx->getFlags().getOutFileType()) {
+ case FT_Elf: {
+ ELFObjectWriter *Writer = Ctx->getObjectWriter();
+ for (const JumpTableData &JumpTable : *Ctx->getJumpTables())
+ Writer->writeJumpTable(JumpTable, llvm::ELF::R_386_32);
+ } break;
+ case FT_Asm:
+ // Already emitted from Cfg
+ break;
+ case FT_Iasm: {
+ if (!BuildDefs::dump())
+ return;
+ Ostream &Str = Ctx->getStrEmit();
+ for (const JumpTableData &JT : *Ctx->getJumpTables()) {
+ Str << "\t.section\t.rodata." << JT.getFunctionName()
+ << "$jumptable,\"a\",@progbits\n";
+ Str << "\t.align\t" << typeWidthInBytes(getPointerType()) << "\n";
+ Str << InstJumpTable::makeName(JT.getFunctionName(), JT.getId()) << ":";
+
+ // On X8632 pointers are 32-bit hence the use of .long
+ for (intptr_t TargetOffset : JT.getTargetOffsets())
+ Str << "\n\t.long\t" << JT.getFunctionName() << "+" << TargetOffset;
+ Str << "\n";
+ }
+ } break;
+ }
+}
+
void TargetDataX8632::lowerGlobals(const VariableDeclarationList &Vars,
const IceString &SectionSuffix) {
switch (Ctx->getFlags().getOutFileType()) {
