[MC] Move EH DWARF encodings from MC to CodeGen, NFC
Summary:
The TType encoding, LSDA encoding, and personality encoding are all
passed explicitly by CodeGen to the assembler through .cfi_* directives,
so only the AsmPrinter needs to know about them.
The FDE CFI encoding however, controls the encoding of the label
implicitly created by the .cfi_startproc directive. That directive seems
to be special in that it doesn't take an encoding, so the assembler just
has to know how to encode one DSO-local label reference from .eh_frame
to .text.
As a result, it looks like MC will continue to have to know when the
large code model is in use. Perhaps we could invent a '.cfi_startproc
[large]' flag so that this knowledge doesn't need to pollute the
assembler.
Reviewers: davide, lliu0, JDevlieghere
Subscribers: hiraditya, fedor.sergeev, llvm-commits
Differential Revision: https://reviews.llvm.org/D50533
llvm-svn: 339397
diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index f6b91a2..2b571a0 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -95,6 +95,156 @@
const TargetMachine &TgtM) {
TargetLoweringObjectFile::Initialize(Ctx, TgtM);
TM = &TgtM;
+
+ bool Large = TgtM.getCodeModel() == CodeModel::Large;
+
+ switch (TgtM.getTargetTriple().getArch()) {
+ case Triple::arm:
+ case Triple::armeb:
+ case Triple::thumb:
+ case Triple::thumbeb:
+ if (Ctx.getAsmInfo()->getExceptionHandlingType() == ExceptionHandling::ARM)
+ break;
+ // Fallthrough if not using EHABI
+ LLVM_FALLTHROUGH;
+ case Triple::ppc:
+ case Triple::x86:
+ PersonalityEncoding = isPositionIndependent()
+ ? dwarf::DW_EH_PE_indirect |
+ dwarf::DW_EH_PE_pcrel |
+ dwarf::DW_EH_PE_sdata4
+ : dwarf::DW_EH_PE_absptr;
+ LSDAEncoding = isPositionIndependent()
+ ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
+ : dwarf::DW_EH_PE_absptr;
+ TTypeEncoding = isPositionIndependent()
+ ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+ dwarf::DW_EH_PE_sdata4
+ : dwarf::DW_EH_PE_absptr;
+ break;
+ case Triple::x86_64:
+ if (isPositionIndependent()) {
+ PersonalityEncoding =
+ dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+ (Large ? dwarf::DW_EH_PE_sdata8 : dwarf::DW_EH_PE_sdata4);
+ LSDAEncoding = dwarf::DW_EH_PE_pcrel |
+ (Large ? dwarf::DW_EH_PE_sdata8 : dwarf::DW_EH_PE_sdata4);
+ TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+ (Large ? dwarf::DW_EH_PE_sdata8 : dwarf::DW_EH_PE_sdata4);
+ } else {
+ PersonalityEncoding =
+ Large ? dwarf::DW_EH_PE_absptr : dwarf::DW_EH_PE_udata4;
+ LSDAEncoding = Large ? dwarf::DW_EH_PE_absptr : dwarf::DW_EH_PE_udata4;
+ TTypeEncoding = Large ? dwarf::DW_EH_PE_absptr : dwarf::DW_EH_PE_udata4;
+ }
+ break;
+ case Triple::hexagon:
+ PersonalityEncoding = dwarf::DW_EH_PE_absptr;
+ LSDAEncoding = dwarf::DW_EH_PE_absptr;
+ TTypeEncoding = dwarf::DW_EH_PE_absptr;
+ if (isPositionIndependent()) {
+ PersonalityEncoding |= dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel;
+ LSDAEncoding |= dwarf::DW_EH_PE_pcrel;
+ TTypeEncoding |= dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel;
+ }
+ break;
+ case Triple::aarch64:
+ case Triple::aarch64_be:
+ // The small model guarantees static code/data size < 4GB, but not where it
+ // will be in memory. Most of these could end up >2GB away so even a signed
+ // pc-relative 32-bit address is insufficient, theoretically.
+ if (isPositionIndependent()) {
+ PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+ dwarf::DW_EH_PE_sdata8;
+ LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
+ TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+ dwarf::DW_EH_PE_sdata8;
+ } else {
+ PersonalityEncoding = dwarf::DW_EH_PE_absptr;
+ LSDAEncoding = dwarf::DW_EH_PE_absptr;
+ TTypeEncoding = dwarf::DW_EH_PE_absptr;
+ }
+ break;
+ case Triple::lanai:
+ LSDAEncoding = dwarf::DW_EH_PE_absptr;
+ PersonalityEncoding = dwarf::DW_EH_PE_absptr;
+ TTypeEncoding = dwarf::DW_EH_PE_absptr;
+ break;
+ case Triple::mips:
+ case Triple::mipsel:
+ case Triple::mips64:
+ case Triple::mips64el:
+ // MIPS uses indirect pointer to refer personality functions and types, so
+ // that the eh_frame section can be read-only. DW.ref.personality will be
+ // generated for relocation.
+ PersonalityEncoding = dwarf::DW_EH_PE_indirect;
+ // FIXME: The N64 ABI probably ought to use DW_EH_PE_sdata8 but we can't
+ // identify N64 from just a triple.
+ TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+ dwarf::DW_EH_PE_sdata4;
+ // We don't support PC-relative LSDA references in GAS so we use the default
+ // DW_EH_PE_absptr for those.
+
+ // FreeBSD must be explicit about the data size and using pcrel since it's
+ // assembler/linker won't do the automatic conversion that the Linux tools
+ // do.
+ if (TgtM.getTargetTriple().isOSFreeBSD()) {
+ PersonalityEncoding |= dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
+ LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
+ }
+ break;
+ case Triple::ppc64:
+ case Triple::ppc64le:
+ PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+ dwarf::DW_EH_PE_udata8;
+ LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8;
+ TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+ dwarf::DW_EH_PE_udata8;
+ break;
+ case Triple::sparcel:
+ case Triple::sparc:
+ if (isPositionIndependent()) {
+ LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
+ PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+ dwarf::DW_EH_PE_sdata4;
+ TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+ dwarf::DW_EH_PE_sdata4;
+ } else {
+ LSDAEncoding = dwarf::DW_EH_PE_absptr;
+ PersonalityEncoding = dwarf::DW_EH_PE_absptr;
+ TTypeEncoding = dwarf::DW_EH_PE_absptr;
+ }
+ break;
+ case Triple::sparcv9:
+ LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
+ if (isPositionIndependent()) {
+ PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+ dwarf::DW_EH_PE_sdata4;
+ TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+ dwarf::DW_EH_PE_sdata4;
+ } else {
+ PersonalityEncoding = dwarf::DW_EH_PE_absptr;
+ TTypeEncoding = dwarf::DW_EH_PE_absptr;
+ }
+ break;
+ case Triple::systemz:
+ // All currently-defined code models guarantee that 4-byte PC-relative
+ // values will be in range.
+ if (isPositionIndependent()) {
+ PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+ dwarf::DW_EH_PE_sdata4;
+ LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
+ TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+ dwarf::DW_EH_PE_sdata4;
+ } else {
+ PersonalityEncoding = dwarf::DW_EH_PE_absptr;
+ LSDAEncoding = dwarf::DW_EH_PE_absptr;
+ TTypeEncoding = dwarf::DW_EH_PE_absptr;
+ }
+ break;
+ default:
+ break;
+ }
}
void TargetLoweringObjectFileELF::emitModuleMetadata(MCStreamer &Streamer,
@@ -684,6 +834,12 @@
MachO::S_MOD_TERM_FUNC_POINTERS,
SectionKind::getData());
}
+
+ PersonalityEncoding =
+ dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
+ LSDAEncoding = dwarf::DW_EH_PE_pcrel;
+ TTypeEncoding =
+ dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
}
void TargetLoweringObjectFileMachO::emitModuleMetadata(MCStreamer &Streamer,