[llvm] r211481 - MC: adjust text section flags for WoA
Saleem Abdulrasool
compnerd at compnerd.org
Sun Jun 22 15:25:01 PDT 2014
Author: compnerd
Date: Sun Jun 22 17:25:01 2014
New Revision: 211481
URL: http://llvm.org/viewvc/llvm-project?rev=211481&view=rev
Log:
MC: adjust text section flags for WoA
Correct the section flags for code built for Windows on ARM with
`-ffunction-sections`. Windows on ARM uses solely Thumb-2 instructions, and
indicates that the function is thumb by placing it in a text section that has
IMAGE_SCN_MEM_16BIT flag set.
When we encounter a .section directive, a new section is constructed. This may
be a text segment. In order to identify that we need the additional flag,
expose the target triple through the ObjectFileInfo as this information is lost
otherwise.
Since any modern ARM targeting environment on Windows would be Thumb-2 (Windows
ARM NT or Windows Embedded Compact), introducing a new flag to indicate the
section attribute seems to be a bit overkill. Simply depend on the target
triple. Since there is one location that this information is currently needed,
creating a target specific assembly parser and delegating the parsing of section
switches also feels a bit heavy handed. If it turns out that this information
ends up changing additional behaviour, then it may be worth considering that
alternative.
Added:
llvm/trunk/test/MC/ARM/Windows/multiple-text-sections.s
Modified:
llvm/trunk/include/llvm/MC/MCObjectFileInfo.h
llvm/trunk/lib/MC/MCObjectFileInfo.cpp
llvm/trunk/lib/MC/MCParser/COFFAsmParser.cpp
Modified: llvm/trunk/include/llvm/MC/MCObjectFileInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCObjectFileInfo.h?rev=211481&r1=211480&r2=211481&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCObjectFileInfo.h (original)
+++ llvm/trunk/include/llvm/MC/MCObjectFileInfo.h Sun Jun 22 17:25:01 2014
@@ -14,13 +14,13 @@
#ifndef LLVM_MC_MCBJECTFILEINFO_H
#define LLVM_MC_MCBJECTFILEINFO_H
+#include "llvm/ADT/Triple.h"
#include "llvm/Support/CodeGen.h"
namespace llvm {
class MCContext;
class MCSection;
class StringRef;
- class Triple;
class MCObjectFileInfo {
protected:
@@ -380,6 +380,7 @@ private:
Reloc::Model RelocM;
CodeModel::Model CMModel;
MCContext *Ctx;
+ Triple TT;
void InitMachOMCObjectFileInfo(Triple T);
void InitELFMCObjectFileInfo(Triple T);
@@ -388,6 +389,9 @@ private:
/// InitEHFrameSection - Initialize EHFrameSection on demand.
///
void InitEHFrameSection();
+
+public:
+ const Triple &getTargetTriple() const { return TT; }
};
} // end namespace llvm
Modified: llvm/trunk/lib/MC/MCObjectFileInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCObjectFileInfo.cpp?rev=211481&r1=211480&r2=211481&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCObjectFileInfo.cpp (original)
+++ llvm/trunk/lib/MC/MCObjectFileInfo.cpp Sun Jun 22 17:25:01 2014
@@ -792,7 +792,7 @@ void MCObjectFileInfo::InitCOFFMCObjectF
SectionKind::getDataRel());
}
-void MCObjectFileInfo::InitMCObjectFileInfo(StringRef TT, Reloc::Model relocm,
+void MCObjectFileInfo::InitMCObjectFileInfo(StringRef T, Reloc::Model relocm,
CodeModel::Model cm,
MCContext &ctx) {
RelocM = relocm;
@@ -817,8 +817,9 @@ void MCObjectFileInfo::InitMCObjectFileI
DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
DwarfAccelTypesSection = nullptr; // Used only by selected targets.
- Triple T(TT);
- Triple::ArchType Arch = T.getArch();
+ TT = Triple(T);
+
+ Triple::ArchType Arch = TT.getArch();
// FIXME: Checking for Arch here to filter out bogus triples such as
// cellspu-apple-darwin. Perhaps we should fix in Triple?
if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
@@ -826,17 +827,17 @@ void MCObjectFileInfo::InitMCObjectFileI
Arch == Triple::arm64 || Arch == Triple::aarch64 ||
Arch == Triple::ppc || Arch == Triple::ppc64 ||
Arch == Triple::UnknownArch) &&
- (T.isOSDarwin() || T.isOSBinFormatMachO())) {
+ (TT.isOSDarwin() || TT.isOSBinFormatMachO())) {
Env = IsMachO;
- InitMachOMCObjectFileInfo(T);
+ InitMachOMCObjectFileInfo(TT);
} else if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
Arch == Triple::arm || Arch == Triple::thumb) &&
- (T.isOSWindows() && T.getObjectFormat() == Triple::COFF)) {
+ (TT.isOSWindows() && TT.getObjectFormat() == Triple::COFF)) {
Env = IsCOFF;
- InitCOFFMCObjectFileInfo(T);
+ InitCOFFMCObjectFileInfo(TT);
} else {
Env = IsELF;
- InitELFMCObjectFileInfo(T);
+ InitELFMCObjectFileInfo(TT);
}
}
Modified: llvm/trunk/lib/MC/MCParser/COFFAsmParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCParser/COFFAsmParser.cpp?rev=211481&r1=211480&r2=211481&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCParser/COFFAsmParser.cpp (original)
+++ llvm/trunk/lib/MC/MCParser/COFFAsmParser.cpp Sun Jun 22 17:25:01 2014
@@ -13,6 +13,7 @@
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCParser/MCAsmLexer.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSectionCOFF.h"
@@ -378,6 +379,11 @@ bool COFFAsmParser::ParseDirectiveSectio
return TokError("unexpected token in directive");
SectionKind Kind = computeSectionKind(Flags);
+ if (Kind.isText()) {
+ const Triple &T = getContext().getObjectFileInfo()->getTargetTriple();
+ if (T.getArch() == Triple::arm || T.getArch() == Triple::thumb)
+ Flags |= COFF::IMAGE_SCN_MEM_16BIT;
+ }
ParseSectionSwitch(SectionName, Flags, Kind, COMDATSymName, Type);
return false;
}
Added: llvm/trunk/test/MC/ARM/Windows/multiple-text-sections.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ARM/Windows/multiple-text-sections.s?rev=211481&view=auto
==============================================================================
--- llvm/trunk/test/MC/ARM/Windows/multiple-text-sections.s (added)
+++ llvm/trunk/test/MC/ARM/Windows/multiple-text-sections.s Sun Jun 22 17:25:01 2014
@@ -0,0 +1,58 @@
+@ RUN: llvm-mc -triple thumbv7-windows-itanium -filetype obj -o - %s \
+@ RUN: | llvm-readobj -s - | FileCheck %s
+
+ .syntax unified
+ .text
+ .thumb
+
+ .section .text,"xr",one_only,a
+
+ .def a;
+ .scl 2;
+ .type 32;
+ .endef
+a:
+ movs r0, #65
+ bx lr
+
+ .section .text,"xr",one_only,b
+
+ .def b;
+ .scl 2;
+ .type 32;
+ .endef
+ .thumb_func
+b:
+ movs r0, #66
+ bx lr
+
+@ CHECK: Sections [
+@ CHECK: Section {
+@ CHECK: Name: .text
+@ CHECK: Characteristics [
+@ CHECK: IMAGE_SCN_CNT_CODE
+@ CHECK: IMAGE_SCN_MEM_16BIT
+@ CHECK: IMAGE_SCN_MEM_EXECUTE
+@ CHECK: IMAGE_SCN_MEM_READ
+@ CHECK: ]
+@ CHECK: }
+@ CHECK: Section {
+@ CHECK: Name: .text
+@ CHECK: Characteristics [
+@ CHECK: IMAGE_SCN_CNT_CODE
+@ CHECK: IMAGE_SCN_MEM_16BIT
+@ CHECK: IMAGE_SCN_MEM_EXECUTE
+@ CHECK: IMAGE_SCN_MEM_READ
+@ CHECK: ]
+@ CHECK: }
+@ CHECK: Section {
+@ CHECK: Name: .text
+@ CHECK: Characteristics [
+@ CHECK: IMAGE_SCN_CNT_CODE
+@ CHECK: IMAGE_SCN_MEM_16BIT
+@ CHECK: IMAGE_SCN_MEM_EXECUTE
+@ CHECK: IMAGE_SCN_MEM_READ
+@ CHECK: ]
+@ CHECK: }
+@ CHECK: ]
+
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