llvm-6502/lib/Target/PowerPC/MCTargetDesc/PPCMCAsmInfo.cpp
Ulrich Weigand c1f4a4b264 [MC/DWARF] Support .debug_frame / .debug_line code alignment factors
I've been comparing the object file output of LLVM's integrated
assembler against the external assembler on PowerPC, and one
area where differences still remain are in DWARF sections.

In particular, the GNU assembler generates .debug_frame and
.debug_line sections using a code alignment factor of 4, since
all PowerPC instructions have size 4 and must be aligned to a
multiple of 4.  However, current MC code hard-codes a code
alignment factor of 1.

This patch changes this by adding a "minimum instruction alignment"
data element to MCAsmInfo and using this as code alignment factor.

This requires passing a MCContext into MCDwarfLineAddr::Encode
and MCDwarfLineAddr::EncodeAdvanceLoc.  Note that one caller,
MCDwarfLineAddr::Write, didn't actually have that information
available.  However, it turns out that this routine is in fact
never used in the whole code base, so the patch simply removes
it.  If it turns out to be needed again at a later time, it
could be re-added with an updated interface.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183834 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-12 14:46:54 +00:00

72 lines
1.9 KiB
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//===-- PPCMCAsmInfo.cpp - PPC asm properties -----------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the declarations of the MCAsmInfoDarwin properties.
//
//===----------------------------------------------------------------------===//
#include "PPCMCAsmInfo.h"
using namespace llvm;
void PPCMCAsmInfoDarwin::anchor() { }
PPCMCAsmInfoDarwin::PPCMCAsmInfoDarwin(bool is64Bit) {
if (is64Bit) {
PointerSize = CalleeSaveStackSlotSize = 8;
}
IsLittleEndian = false;
PCSymbol = ".";
CommentString = ";";
ExceptionsType = ExceptionHandling::DwarfCFI;
if (!is64Bit)
Data64bitsDirective = 0; // We can't emit a 64-bit unit in PPC32 mode.
AssemblerDialect = 1; // New-Style mnemonics.
SupportsDebugInformation= true; // Debug information.
}
void PPCLinuxMCAsmInfo::anchor() { }
PPCLinuxMCAsmInfo::PPCLinuxMCAsmInfo(bool is64Bit) {
if (is64Bit) {
PointerSize = CalleeSaveStackSlotSize = 8;
}
IsLittleEndian = false;
// ".comm align is in bytes but .align is pow-2."
AlignmentIsInBytes = false;
CommentString = "#";
GlobalPrefix = "";
PrivateGlobalPrefix = ".L";
WeakRefDirective = "\t.weak\t";
// Uses '.section' before '.bss' directive
UsesELFSectionDirectiveForBSS = true;
// Debug Information
SupportsDebugInformation = true;
PCSymbol = ".";
// Set up DWARF directives
HasLEB128 = true; // Target asm supports leb128 directives (little-endian)
MinInstAlignment = 4;
// Exceptions handling
ExceptionsType = ExceptionHandling::DwarfCFI;
ZeroDirective = "\t.space\t";
Data64bitsDirective = is64Bit ? "\t.quad\t" : 0;
AssemblerDialect = 0; // Old-Style mnemonics.
}