[llvm-commits] [llvm] r81404 - in /llvm/trunk/lib/CodeGen/AsmPrinter: DwarfException.cpp DwarfException.h
Bill Wendling
wendling at apple.com
Wed Sep 9 17:02:05 PDT 2009
This had some formatting changes in it. Sorry about that. There are
only a few of them, though, so I went ahead with the one commit
instead of two...
-bw
On Sep 9, 2009, at 4:56 PM, Bill Wendling wrote:
> Author: void
> Date: Wed Sep 9 18:56:55 2009
> New Revision: 81404
>
> URL: http://llvm.org/viewvc/llvm-project?rev=81404&view=rev
> Log:
> Believe it or not, this is a simplification. :-)
>
> Basically, this patch is working towards removing the hard-coded
> values that are
> output for the CIE. In particular, the CIE augmentation and the CIE
> augmentation
> size. Both of these should be calculated. In the process, I was able
> to make a
> bunch of code simpler.
>
> The encodings for the personality, LSDA, and FDE in the CIE are
> still not
> correct. They should be generated either from target-specific
> callbacks (blech!)
> or grokked from first-principles.
>
> Modified:
> llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp
> llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.h
>
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp?rev=81404&r1=81403&r2=81404&view=diff
>
> =
> =
> =
> =
> =
> =
> =
> =
> ======================================================================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp Wed Sep 9
> 18:56:55 2009
> @@ -51,6 +51,25 @@
> delete ExceptionTimer;
> }
>
> +unsigned DwarfException::SizeOfEncodedValue(unsigned Encoding) {
> + if (Encoding == dwarf::DW_EH_PE_omit)
> + return 0;
> +
> + switch (Encoding & 0x07) {
> + case dwarf::DW_EH_PE_absptr:
> + return TD->getPointerSize();
> + case dwarf::DW_EH_PE_udata2:
> + return 2;
> + case dwarf::DW_EH_PE_udata4:
> + return 4;
> + case dwarf::DW_EH_PE_udata8:
> + return 8;
> + }
> +
> + llvm_unreachable("Invalid encoded value.");
> + return 0;
> +}
> +
> /// EmitCIE - Emit a Common Information Entry (CIE). This holds
> information that
> /// is shared among many Frame Description Entries. There is at
> least one CIE
> /// in every non-empty .debug_frame section.
> @@ -87,7 +106,40 @@
>
> // The personality presence indicates that language specific
> information will
> // show up in the eh frame.
> - Asm->EmitString(Personality ? "zPLR" : "zR");
> +
> + // FIXME: Don't hardcode these encodings.
> + unsigned PerEncoding = dwarf::DW_EH_PE_pcrel |
> dwarf::DW_EH_PE_sdata4;
> + if (Personality && MAI->getNeedsIndirectEncoding())
> + PerEncoding |= dwarf::DW_EH_PE_indirect;
> + unsigned LSDAEncoding = dwarf::DW_EH_PE_pcrel |
> dwarf::DW_EH_PE_sdata4;
> + unsigned FDEEncoding = dwarf::DW_EH_PE_pcrel |
> dwarf::DW_EH_PE_sdata4;
> +
> + char Augmentation[5] = { 0 };
> + unsigned AugmentationSize = 0;
> + char *APtr = Augmentation + 1;
> +
> + if (Personality) {
> + // There is a personality function.
> + *APtr++ = 'P';
> + AugmentationSize += 1 + SizeOfEncodedValue(PerEncoding);
> + }
> +
> + if (UsesLSDA[Index]) {
> + // An LSDA pointer is in the FDE augmentation.
> + *APtr++ = 'L';
> + ++AugmentationSize;
> + }
> +
> + if (FDEEncoding != dwarf::DW_EH_PE_absptr) {
> + // A non-default pointer encoding for the FDE.
> + *APtr++ = 'R';
> + ++AugmentationSize;
> + }
> +
> + if (APtr != Augmentation + 1)
> + Augmentation[0] = 'z';
> +
> + Asm->EmitString(Augmentation);
> Asm->EOL("CIE Augmentation");
>
> // Round out reader.
> @@ -98,22 +150,14 @@
> Asm->EmitInt8(RI->getDwarfRegNum(RI->getRARegister(), true));
> Asm->EOL("CIE Return Address Column");
>
> - // If there is a personality, we need to indicate the function's
> location.
> - if (Personality) {
> - Asm->EmitULEB128Bytes(7);
> - Asm->EOL("Augmentation Size");
> + Asm->EmitULEB128Bytes(AugmentationSize);
> + Asm->EOL("Augmentation Size");
>
> - if (MAI->getNeedsIndirectEncoding()) {
> - Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4 |
> - dwarf::DW_EH_PE_indirect);
> - Asm->EOL("Personality",
> - dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4 |
> - dwarf::DW_EH_PE_indirect);
> - } else {
> - Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
> - Asm->EOL("Personality", dwarf::DW_EH_PE_pcrel |
> dwarf::DW_EH_PE_sdata4);
> - }
> + Asm->EmitInt8(PerEncoding);
> + Asm->EOL("Personality", PerEncoding);
>
> + // If there is a personality, we need to indicate the function's
> location.
> + if (Personality) {
> PrintRelDirective(true);
> O << MAI->getPersonalityPrefix();
> Asm->EmitExternalGlobal((const GlobalVariable *)(Personality));
> @@ -122,17 +166,11 @@
> O << "-" << MAI->getPCSymbol();
> Asm->EOL("Personality");
>
> - Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
> - Asm->EOL("LSDA Encoding", dwarf::DW_EH_PE_pcrel |
> dwarf::DW_EH_PE_sdata4);
> + Asm->EmitInt8(LSDAEncoding);
> + Asm->EOL("LSDA Encoding", LSDAEncoding);
>
> - Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
> - Asm->EOL("FDE Encoding", dwarf::DW_EH_PE_pcrel |
> dwarf::DW_EH_PE_sdata4);
> - } else {
> - Asm->EmitULEB128Bytes(1);
> - Asm->EOL("Augmentation Size");
> -
> - Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
> - Asm->EOL("FDE Encoding", dwarf::DW_EH_PE_pcrel |
> dwarf::DW_EH_PE_sdata4);
> + Asm->EmitInt8(FDEEncoding);
> + Asm->EOL("FDE Encoding", FDEEncoding);
> }
>
> // Indicate locations of general callee saved registers in frame.
> @@ -216,10 +254,10 @@
> if (EHFrameInfo.hasLandingPads)
> EmitReference("exception", EHFrameInfo.Number, true, false);
> else {
> - if (is4Byte)
> - Asm->EmitInt32((int)0);
> - else
> - Asm->EmitInt64((int)0);
> + if (is4Byte)
> + Asm->EmitInt32((int)0);
> + else
> + Asm->EmitInt64((int)0);
> }
> Asm->EOL("Language Specific Data Area");
> } else {
> @@ -854,19 +892,20 @@
> if (MAI->getExceptionHandlingType() != ExceptionHandling::Dwarf)
> return;
>
> + if (!shouldEmitMovesModule && !shouldEmitTableModule)
> + return;
> +
> if (TimePassesIsEnabled)
> ExceptionTimer->startTimer();
>
> - if (shouldEmitMovesModule || shouldEmitTableModule) {
> - const std::vector<Function *> Personalities = MMI-
> >getPersonalities();
> + const std::vector<Function *> Personalities = MMI-
> >getPersonalities();
>
> - for (unsigned i = 0, e = Personalities.size(); i < e; ++i)
> - EmitCIE(Personalities[i], i);
> + for (unsigned i = 0, e = Personalities.size(); i < e; ++i)
> + EmitCIE(Personalities[i], i);
>
> - for (std::vector<FunctionEHFrameInfo>::iterator
> - I = EHFrames.begin(), E = EHFrames.end(); I != E; ++I)
> - EmitFDE(*I);
> - }
> + for (std::vector<FunctionEHFrameInfo>::iterator
> + I = EHFrames.begin(), E = EHFrames.end(); I != E; ++I)
> + EmitFDE(*I);
>
> if (TimePassesIsEnabled)
> ExceptionTimer->stopTimer();
> @@ -925,6 +964,9 @@
> MMI->getFrameMoves(),
> MF->getFunction()));
>
> + // Record if this personality index uses a landing pad.
> + UsesLSDA[MMI->getPersonalityIndex()] |= !MMI->getLandingPads
> ().empty();
> +
> if (TimePassesIsEnabled)
> ExceptionTimer->stopTimer();
> }
>
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.h?rev=81404&r1=81403&r2=81404&view=diff
>
> =
> =
> =
> =
> =
> =
> =
> =
> ======================================================================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.h (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.h Wed Sep 9
> 18:56:55 2009
> @@ -51,6 +51,11 @@
>
> std::vector<FunctionEHFrameInfo> EHFrames;
>
> + /// UsesLSDA - Indicates whether an FDE that uses the CIE at the
> given index
> + /// uses an LSDA. If so, then we need to encode that information
> in the CIE's
> + /// augmentation.
> + DenseMap<unsigned, bool> UsesLSDA;
> +
> /// shouldEmitTable - Per-function flag to indicate if EH tables
> should
> /// be emitted.
> bool shouldEmitTable;
> @@ -70,6 +75,8 @@
> /// ExceptionTimer - Timer for the Dwarf exception writer.
> Timer *ExceptionTimer;
>
> + unsigned SizeOfEncodedValue(unsigned Encoding);
> +
> /// EmitCIE - Emit a Common Information Entry (CIE). This holds
> information
> /// that is shared among many Frame Description Entries. There is
> at least
> /// one CIE in every non-empty .debug_frame section.
>
>
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