[PATCH][X86_64/MC] Towards usable Win64 exception handling
Kai Nacke
kai.nacke at redstar.de
Fri May 31 04:43:57 PDT 2013
Ping^2.
After finding yet another issue I realized that the patch was getting
far too big. Therefore I splitted the patch into 4 parts.
The first patch fixes the failing seh.s test. The second patch changes
the relocation type to IMAGE_REL_AMD64_ADDR32NB as required by the MS
COFF spec. The third patch adresses an alignment problem inside the
unwind info data structure (this one is new). The fourth patch outputs
the personality function and the language data into the right places.
Each patch except the last one contains test cases. Currently, there is
no code path in LLVM to trigger the changed code. I will add test cases
for this with my next patch which will add support for Win64 EH to LLVM.
@Anton
I am CC'ing you because you reviewed my MC patches the last time.
Regards
Kai
On 22.05.2013 07:59, Kai Nacke wrote:
> Ping.
>
> On 18.05.2013 14:49, Kai Nacke wrote:
>> Hi!
>>
>> On 17.05.2013 22:00, Rafael Espíndola wrote:
>> > needs a testcase.
>>
>> I realized that the main test case is currently marked as XFAIL because
>> of a wrong offset for unwind code SET_FP. I also fixed this, re-enabled
>> the test case and added a check for the changed relocation type.
>>
>> Every aspect of this patch should now be covered by a test.
>>
>> Regards
>> Kai
>>
>> On 17.05.2013 16:27, Kai Nacke wrote:
>>> Hi!
>>>
>>> This patch fixes a couple of problems in the Win64 EH code.
>>>
>>> - The emitted EH handler is now the personality function specified in
>>> the IR instead of the hard coded _GCC_specific_handler
>>> (_GCC_specific_handler is not called from SEH code - it's
>>> __gcc_personality_seh0. Specify this as personality function if you like
>>> to try the GCC code.)
>>>
>>> - The Dwarf EH code ("gcc_except_table") is no longer emitted into a
>>> separate section but into the UNWIND_INFO structure as language specific
>>> handler data. A pointer to this data is passed in field
>>> DISPATCHER_CONTEXT->HandlerData to the personality function.
>>>
>>> - All relocations now use the VK_COFF_IMGREL32 modifier. This is
>>> required by the COFF specification and keeps the MS LINK tool happy. The
>>> linker flag /LARGEADDRESSAWARE:NO is no longer required.
>>>
>>> - Begin and end address of a function are now expressed as offsets from
>>> the function symbol instead of emitting the temporary labels. The latter
>>> approach didn't work with the VK_COFF_IMGREL32 modifier. Nice side
>>> effect is that llvm-objdump now displays the function symbol, too.
>>>
>>> Using this patch and a modified version of the patch to create the
>>> unwinding code from Charles Davis I am able to raise an exception
>>> via RaiseException and get the personality function called. :-)
>>>
>>> Please review. (BTW: This patch supersedes my mail "MCWin64EH:
>>> reloctions must be IMGREL32")
>>>
>>> Regards
>>> Kai
>>>
>>>
>>> _______________________________________________
>>> llvm-commits mailing list
>>> llvm-commits at cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>>>
>>
>>
>>
>> _______________________________________________
>> llvm-commits mailing list
>> llvm-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>>
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>
-------------- next part --------------
>From 357b1f4a471d95cdd36400a878e2f035e5a8f7f7 Mon Sep 17 00:00:00 2001
From: kai <kai at redstar.de>
Date: Mon, 27 May 2013 07:32:17 +0200
Subject: [PATCH 1/5] Fix failing test seh.s
The code offset for unwind code SET_FPREG is wrong because it
is set to constant 0. The fix is to do the same as for the other
unwind codes: emit a label and later the absolute difference
between the label and the begin of the prologue.
---
lib/MC/MCStreamer.cpp | 4 +++-
lib/MC/MCWin64EH.cpp | 5 ++---
test/MC/COFF/seh.s | 2 --
test/tools/llvm-objdump/win64-unwind-data.s | 2 +-
4 files changed, 6 insertions(+), 7 deletions(-)
diff --git a/lib/MC/MCStreamer.cpp b/lib/MC/MCStreamer.cpp
index 8f1895e..6e0c5e5 100644
--- a/lib/MC/MCStreamer.cpp
+++ b/lib/MC/MCStreamer.cpp
@@ -472,7 +472,9 @@ void MCStreamer::EmitWin64EHSetFrame(unsigned Register, unsigned Offset) {
report_fatal_error("Frame register and offset already specified!");
if (Offset & 0x0F)
report_fatal_error("Misaligned frame pointer offset!");
- MCWin64EHInstruction Inst(Win64EH::UOP_SetFPReg, 0, Register, Offset);
+ MCSymbol *Label = getContext().CreateTempSymbol();
+ MCWin64EHInstruction Inst(Win64EH::UOP_SetFPReg, Label, Register, Offset);
+ EmitLabel(Label);
CurFrame->LastFrameInst = CurFrame->Instructions.size();
CurFrame->Instructions.push_back(Inst);
}
diff --git a/lib/MC/MCWin64EH.cpp b/lib/MC/MCWin64EH.cpp
index c5b637c..8db1fa2 100644
--- a/lib/MC/MCWin64EH.cpp
+++ b/lib/MC/MCWin64EH.cpp
@@ -64,7 +64,7 @@ static void EmitAbsDifference(MCStreamer &streamer, MCSymbol *lhs,
static void EmitUnwindCode(MCStreamer &streamer, MCSymbol *begin,
MCWin64EHInstruction &inst) {
- uint8_t b1, b2;
+ uint8_t b2;
uint16_t w;
b2 = (inst.getOperation() & 0x0F);
switch (inst.getOperation()) {
@@ -93,8 +93,7 @@ static void EmitUnwindCode(MCStreamer &streamer, MCSymbol *begin,
streamer.EmitIntValue(b2, 1);
break;
case Win64EH::UOP_SetFPReg:
- b1 = inst.getOffset() & 0xF0;
- streamer.EmitIntValue(b1, 1);
+ EmitAbsDifference(streamer, inst.getLabel(), begin);
streamer.EmitIntValue(b2, 1);
break;
case Win64EH::UOP_SaveNonVol:
diff --git a/test/MC/COFF/seh.s b/test/MC/COFF/seh.s
index bef425e..b1e61a9 100644
--- a/test/MC/COFF/seh.s
+++ b/test/MC/COFF/seh.s
@@ -1,7 +1,5 @@
// This test checks that the SEH directives emit the correct unwind data.
-// TODO: Expected fail because SET_FPREG has a wrong offset.
-// XFAIL: *
// RUN: llvm-mc -triple x86_64-pc-win32 -filetype=obj %s | llvm-readobj -s -u | FileCheck %s
// CHECK: Sections [
diff --git a/test/tools/llvm-objdump/win64-unwind-data.s b/test/tools/llvm-objdump/win64-unwind-data.s
index 1e4c742..a172bfc 100644
--- a/test/tools/llvm-objdump/win64-unwind-data.s
+++ b/test/tools/llvm-objdump/win64-unwind-data.s
@@ -13,7 +13,7 @@
// CHECK-NEXT: Frame register: RBX
// CHECK-NEXT: Frame offset: 0
// CHECK-NEXT: Unwind Codes:
-// CHECK-NEXT: 0x00: UOP_SetFPReg
+// CHECK-NEXT: 0x12: UOP_SetFPReg
// CHECK-NEXT: 0x0f: UOP_PushNonVol RBX
// CHECK-NEXT: 0x0e: UOP_SaveXMM128 XMM8 [0x0000]
// CHECK-NEXT: 0x09: UOP_SaveNonVol RSI [0x0010]
--
1.8.0.msysgit.0
-------------- next part --------------
>From cbf320d5306e10ada1e8095a5cd6ead4e5f20932 Mon Sep 17 00:00:00 2001
From: kai <kai at redstar.de>
Date: Mon, 27 May 2013 09:06:18 +0200
Subject: [PATCH 2/5] Generate IMAGE_REL_AMD64_ADDR32NB relocations for SEH
data structures.
The Win64 EH data structures must be of type IMAGE_REL_AMD64_ADDR32NB
instead of IMAGE_REL_AMD64_ADDR32. This is easiely achieved by adding
the VK_COFF_IMGREL32 modifier to the symbol reference.
Change also references to start and end of the SEH range of a function
as offsets to start of the function.
---
lib/MC/MCWin64EH.cpp | 26 +++++++++++++++++++++-----
test/MC/COFF/seh.s | 23 ++++++++++++++++++++++-
test/tools/llvm-objdump/win64-unwind-data.s | 20 ++++++++++----------
3 files changed, 53 insertions(+), 16 deletions(-)
diff --git a/lib/MC/MCWin64EH.cpp b/lib/MC/MCWin64EH.cpp
index 8db1fa2..c3d568b 100644
--- a/lib/MC/MCWin64EH.cpp
+++ b/lib/MC/MCWin64EH.cpp
@@ -128,14 +128,29 @@ static void EmitUnwindCode(MCStreamer &streamer, MCSymbol *begin,
}
}
+static void EmitSymbolRefWithOfs(MCStreamer &streamer,
+ const MCSymbol *Base,
+ const MCSymbol *Other) {
+ MCContext &Context = streamer.getContext();
+ const MCSymbolRefExpr *BaseRef = MCSymbolRefExpr::Create(Base, Context);
+ const MCSymbolRefExpr *OtherRef = MCSymbolRefExpr::Create(Other, Context);
+ const MCExpr *Ofs = MCBinaryExpr::CreateSub(OtherRef, BaseRef, Context);
+ const MCSymbolRefExpr *BaseRefRel = MCSymbolRefExpr::Create(Base,
+ MCSymbolRefExpr::VK_COFF_IMGREL32,
+ Context);
+ streamer.EmitValue(MCBinaryExpr::CreateAdd(BaseRefRel, Ofs, Context), 4);
+}
+
static void EmitRuntimeFunction(MCStreamer &streamer,
const MCWin64EHUnwindInfo *info) {
MCContext &context = streamer.getContext();
streamer.EmitValueToAlignment(4);
- streamer.EmitValue(MCSymbolRefExpr::Create(info->Begin, context), 4);
- streamer.EmitValue(MCSymbolRefExpr::Create(info->End, context), 4);
- streamer.EmitValue(MCSymbolRefExpr::Create(info->Symbol, context), 4);
+ EmitSymbolRefWithOfs(streamer, info->Function, info->Begin);
+ EmitSymbolRefWithOfs(streamer, info->Function, info->End);
+ streamer.EmitValue(MCSymbolRefExpr::Create(info->Symbol,
+ MCSymbolRefExpr::VK_COFF_IMGREL32,
+ context), 4);
}
static void EmitUnwindInfo(MCStreamer &streamer, MCWin64EHUnwindInfo *info) {
@@ -188,8 +203,9 @@ static void EmitUnwindInfo(MCStreamer &streamer, MCWin64EHUnwindInfo *info) {
EmitRuntimeFunction(streamer, info->ChainedParent);
else if (flags &
((Win64EH::UNW_TerminateHandler|Win64EH::UNW_ExceptionHandler) << 3))
- streamer.EmitValue(MCSymbolRefExpr::Create(info->ExceptionHandler, context),
- 4);
+ streamer.EmitValue(MCSymbolRefExpr::Create(info->ExceptionHandler,
+ MCSymbolRefExpr::VK_COFF_IMGREL32,
+ context), 4);
else if (numCodes < 2) {
// The minimum size of an UNWIND_INFO struct is 8 bytes. If we're not
// a chained unwind info, if there is no handler, and if there are fewer
diff --git a/test/MC/COFF/seh.s b/test/MC/COFF/seh.s
index b1e61a9..72d42f4 100644
--- a/test/MC/COFF/seh.s
+++ b/test/MC/COFF/seh.s
@@ -1,6 +1,6 @@
// This test checks that the SEH directives emit the correct unwind data.
-// RUN: llvm-mc -triple x86_64-pc-win32 -filetype=obj %s | llvm-readobj -s -u | FileCheck %s
+// RUN: llvm-mc -triple x86_64-pc-win32 -filetype=obj %s | llvm-readobj -s -u -r | FileCheck %s
// CHECK: Sections [
// CHECK: Section {
@@ -34,6 +34,27 @@
// CHECK-NEXT: }
// CHECK-NEXT: ]
+// CHECK-NEXT: Relocations [
+// CHECK-NEXT: Section (2) .xdata {
+// CHECK-NEXT: 0x14 IMAGE_REL_AMD64_ADDR32NB __C_specific_handler
+// CHECK-NEXT: 0x20 IMAGE_REL_AMD64_ADDR32NB func
+// CHECK-NEXT: 0x24 IMAGE_REL_AMD64_ADDR32NB func
+// CHECK-NEXT: 0x28 IMAGE_REL_AMD64_ADDR32NB .xdata
+// CHECK-NEXT: }
+// CHECK-NEXT: Section (3) .pdata {
+// CHECK-NEXT: 0x0 IMAGE_REL_AMD64_ADDR32NB func
+// CHECK-NEXT: 0x4 IMAGE_REL_AMD64_ADDR32NB func
+// CHECK-NEXT: 0x8 IMAGE_REL_AMD64_ADDR32NB .xdata
+// CHECK-NEXT: 0xC IMAGE_REL_AMD64_ADDR32NB func
+// CHECK-NEXT: 0x10 IMAGE_REL_AMD64_ADDR32NB func
+// CHECK-NEXT: 0x14 IMAGE_REL_AMD64_ADDR32NB .xdata
+// CHECK-NEXT: 0x18 IMAGE_REL_AMD64_ADDR32NB smallFunc
+// CHECK-NEXT: 0x1C IMAGE_REL_AMD64_ADDR32NB smallFunc
+// CHECK-NEXT: 0x20 IMAGE_REL_AMD64_ADDR32NB .xdata
+// CHECK-NEXT: }
+// CHECK-NEXT: ]
+
+
// CHECK: UnwindInformation [
// CHECK-NEXT: RuntimeFunction {
// CHECK-NEXT: StartAddress: [[CodeSect1:[^ ]+]] [[BeginDisp1:(\+0x[A-F0-9]+)?]]
diff --git a/test/tools/llvm-objdump/win64-unwind-data.s b/test/tools/llvm-objdump/win64-unwind-data.s
index a172bfc..f8463fb 100644
--- a/test/tools/llvm-objdump/win64-unwind-data.s
+++ b/test/tools/llvm-objdump/win64-unwind-data.s
@@ -3,8 +3,8 @@
// CHECK: Unwind info:
// CHECK: Function Table:
-// CHECK-NEXT: Start Address: .text
-// CHECK-NEXT: End Address: .text + 0x001b
+// CHECK-NEXT: Start Address: func
+// CHECK-NEXT: End Address: func + 0x001b
// CHECK-NEXT: Unwind Info Address: .xdata
// CHECK-NEXT: Version: 1
// CHECK-NEXT: Flags: 1 UNW_ExceptionHandler
@@ -20,8 +20,8 @@
// CHECK-NEXT: 0x04: UOP_AllocSmall 24
// CHECK-NEXT: 0x00: UOP_PushMachFrame w/o error code
// CHECK: Function Table:
-// CHECK-NEXT: Start Address: .text + 0x0012
-// CHECK-NEXT: End Address: .text + 0x0012
+// CHECK-NEXT: Start Address: func + 0x0012
+// CHECK-NEXT: End Address: func + 0x0012
// CHECK-NEXT: Unwind Info Address: .xdata + 0x001c
// CHECK-NEXT: Version: 1
// CHECK-NEXT: Flags: 4 UNW_ChainInfo
@@ -29,8 +29,8 @@
// CHECK-NEXT: Number of Codes: 0
// CHECK-NEXT: No frame pointer used
// CHECK: Function Table:
-// CHECK-NEXT: Start Address: .text + 0x001b
-// CHECK-NEXT: End Address: .text + 0x001c
+// CHECK-NEXT: Start Address: smallFunc
+// CHECK-NEXT: End Address: smallFunc + 0x0001
// CHECK-NEXT: Unwind Info Address: .xdata + 0x002c
// CHECK-NEXT: Version: 1
// CHECK-NEXT: Flags: 0
@@ -38,8 +38,8 @@
// CHECK-NEXT: Number of Codes: 0
// CHECK-NEXT: No frame pointer used
// CHECK: Function Table:
-// CHECK-NEXT: Start Address: .text + 0x001c
-// CHECK-NEXT: End Address: .text + 0x0039
+// CHECK-NEXT: Start Address: allocFunc
+// CHECK-NEXT: End Address: allocFunc + 0x001d
// CHECK-NEXT: Unwind Info Address: .xdata + 0x0034
// CHECK-NEXT: Version: 1
// CHECK-NEXT: Flags: 0
@@ -90,9 +90,9 @@ smallFunc:
.seh_endproc
// Function with big stack allocation.
- .globl smallFunc
+ .globl allocFunc
.def allocFunc; .scl 2; .type 32; .endef
- .seh_proc smallFunc
+ .seh_proc allocFunc
allocFunc:
.seh_pushframe @code
subq $65520, %rsp
--
1.8.0.msysgit.0
-------------- next part --------------
>From c2bd346fb968caec41ccec0de7fba5ad35180744 Mon Sep 17 00:00:00 2001
From: kai <kai at redstar.de>
Date: Tue, 28 May 2013 06:37:39 +0200
Subject: [PATCH 3/5] Fix alignment of unwind data.
For alignment purposes, the instruction array will always have an even
number of entries, with the final entry potentially unused (in which case
the array will be one longer than indicated by the count of unwind codes
field).
---
lib/MC/MCWin64EH.cpp | 19 +++++++----
test/MC/COFF/seh-align1.s | 65 +++++++++++++++++++++++++++++++++++++
test/MC/COFF/seh-align2.s | 78 ++++++++++++++++++++++++++++++++++++++++++++
test/MC/COFF/seh-align3.s | 83 +++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 238 insertions(+), 7 deletions(-)
create mode 100644 test/MC/COFF/seh-align1.s
create mode 100644 test/MC/COFF/seh-align2.s
create mode 100644 test/MC/COFF/seh-align3.s
diff --git a/lib/MC/MCWin64EH.cpp b/lib/MC/MCWin64EH.cpp
index c3d568b..b8b07d3 100644
--- a/lib/MC/MCWin64EH.cpp
+++ b/lib/MC/MCWin64EH.cpp
@@ -159,11 +159,11 @@ static void EmitUnwindInfo(MCStreamer &streamer, MCWin64EHUnwindInfo *info) {
MCContext &context = streamer.getContext();
streamer.EmitValueToAlignment(4);
- // Upper 3 bits are the version number (currently 1).
- uint8_t flags = 0x01;
info->Symbol = context.CreateTempSymbol();
streamer.EmitLabel(info->Symbol);
+ // Upper 3 bits are the version number (currently 1).
+ uint8_t flags = 0x01;
if (info->ChainedParent)
flags |= Win64EH::UNW_ChainInfo << 3;
else {
@@ -199,6 +199,14 @@ static void EmitUnwindInfo(MCStreamer &streamer, MCWin64EHUnwindInfo *info) {
EmitUnwindCode(streamer, info->Begin, inst);
}
+ // For alignment purposes, the instruction array will always have an even
+ // number of entries, with the final entry potentially unused (in which case
+ // the array will be one longer than indicated by the count of unwind codes
+ // field).
+ if (numCodes & 1) {
+ streamer.EmitIntValue(0, 2);
+ }
+
if (flags & (Win64EH::UNW_ChainInfo << 3))
EmitRuntimeFunction(streamer, info->ChainedParent);
else if (flags &
@@ -206,14 +214,11 @@ static void EmitUnwindInfo(MCStreamer &streamer, MCWin64EHUnwindInfo *info) {
streamer.EmitValue(MCSymbolRefExpr::Create(info->ExceptionHandler,
MCSymbolRefExpr::VK_COFF_IMGREL32,
context), 4);
- else if (numCodes < 2) {
+ else if (numCodes == 0) {
// The minimum size of an UNWIND_INFO struct is 8 bytes. If we're not
// a chained unwind info, if there is no handler, and if there are fewer
// than 2 slots used in the unwind code array, we have to pad to 8 bytes.
- if (numCodes == 1)
- streamer.EmitIntValue(0, 2);
- else
- streamer.EmitIntValue(0, 4);
+ streamer.EmitIntValue(0, 4);
}
}
diff --git a/test/MC/COFF/seh-align1.s b/test/MC/COFF/seh-align1.s
new file mode 100644
index 0000000..aafc6ed
--- /dev/null
+++ b/test/MC/COFF/seh-align1.s
@@ -0,0 +1,65 @@
+// This test checks the alignment and padding of the unwind info.
+
+// RUN: llvm-mc -triple x86_64-pc-win32 -filetype=obj %s | llvm-readobj -s -sd -sr -u | FileCheck %s
+
+// CHECK: Sections [
+// CHECK: Section {
+// CHECK: Name: .xdata
+// CHECK: RawDataSize: 8
+// CHECK: RelocationCount: 0
+// CHECK: Characteristics [
+// CHECK-NEXT: ALIGN_4BYTES
+// CHECK-NEXT: CNT_INITIALIZED_DATA
+// CHECK-NEXT: MEM_READ
+// CHECK-NEXT: ]
+// CHECK: Relocations [
+// CHECK-NEXT: ]
+// CHECK: SectionData (
+// CHECK-NEXT: 0000: 01000000 00000000
+// CHECK-NEXT: )
+// CHECK-NEXT: }
+// CHECK: Section {
+// CHECK: Name: .pdata
+// CHECK: RawDataSize: 12
+// CHECK: RelocationCount: 3
+// CHECK: Characteristics [
+// CHECK-NEXT: IMAGE_SCN_ALIGN_4BYTES
+// CHECK-NEXT: IMAGE_SCN_CNT_INITIALIZED_DATA
+// CHECK-NEXT: IMAGE_SCN_MEM_READ
+// CHECK-NEXT: ]
+// CHECK: Relocations [
+// CHECK-NEXT: [[BeginDisp:0x[A-F0-9]+]] IMAGE_REL_AMD64_ADDR32NB smallFunc
+// CHECK-NEXT: [[EndDisp:0x[A-F0-9]+]] IMAGE_REL_AMD64_ADDR32NB smallFunc
+// CHECK-NEXT: [[UnwindDisp:0x[A-F0-9]+]] IMAGE_REL_AMD64_ADDR32NB .xdata
+// CHECK-NEXT: ]
+// CHECK: SectionData (
+// CHECK-NEXT: 0000: 00000000 01000000 00000000
+// CHECK-NEXT: )
+// CHECK-NEXT: }
+// CHECK: UnwindInformation [
+// CHECK-NEXT: RuntimeFunction {
+// CHECK-NEXT: StartAddress: smallFunc {{(\+0x[A-F0-9]+ )?}}([[BeginDisp]])
+// CHECK-NEXT: EndAddress: smallFunc {{(\+0x[A-F0-9]+ )?}}([[EndDisp]])
+// CHECK-NEXT: UnwindInfoAddress: .xdata {{(\+0x[A-F0-9]+ )?}}([[UnwindDisp]])
+// CHECK-NEXT: UnwindInfo {
+// CHECK-NEXT: Version: 1
+// CHECK-NEXT: Flags [
+// CHECK-NEXT: ]
+// CHECK-NEXT: PrologSize: 0
+// CHECK-NEXT: FrameRegister: -
+// CHECK-NEXT: FrameOffset: -
+// CHECK-NEXT: UnwindCodeCount: 0
+// CHECK-NEXT: UnwindCodes [
+// CHECK-NEXT: ]
+// CHECK-NEXT: }
+// CHECK-NEXT: }
+// CHECK-NEXT: ]
+
+// Generate the minimal unwind info.
+// It contains only the version set to 1. All other bytes are 0.
+ .globl smallFunc
+ .def smallFunc; .scl 2; .type 32; .endef
+ .seh_proc smallFunc
+smallFunc:
+ ret
+ .seh_endproc
diff --git a/test/MC/COFF/seh-align2.s b/test/MC/COFF/seh-align2.s
new file mode 100644
index 0000000..5e6c49a
--- /dev/null
+++ b/test/MC/COFF/seh-align2.s
@@ -0,0 +1,78 @@
+// This test checks the alignment and padding of the unwind info.
+
+// RUN: llvm-mc -triple x86_64-pc-win32 -filetype=obj %s | llvm-readobj -s -sd -sr -u | FileCheck %s
+
+// CHECK: Sections [
+// CHECK: Section {
+// CHECK: Name: .xdata
+// CHECK: RawDataSize: 16
+// CHECK: RelocationCount: 1
+// CHECK: Characteristics [
+// CHECK-NEXT: ALIGN_4BYTES
+// CHECK-NEXT: CNT_INITIALIZED_DATA
+// CHECK-NEXT: MEM_READ
+// CHECK-NEXT: ]
+// CHECK: Relocations [
+// CHECK-NEXT: [[HandlerDisp:0x[A-F0-9]+]] IMAGE_REL_AMD64_ADDR32NB __C_specific_handler
+// CHECK-NEXT: ]
+// CHECK: SectionData (
+// CHECK-NEXT: 0000: 09000100 04220000 00000000 BEBAFECA
+// CHECK-NEXT: )
+// CHECK-NEXT: }
+// CHECK-NEXT: Section {
+// CHECK: Name: .pdata
+// CHECK: RawDataSize: 12
+// CHECK: RelocationCount: 3
+// CHECK: Characteristics [
+// CHECK-NEXT: IMAGE_SCN_ALIGN_4BYTES
+// CHECK-NEXT: IMAGE_SCN_CNT_INITIALIZED_DATA
+// CHECK-NEXT: IMAGE_SCN_MEM_READ
+// CHECK-NEXT: ]
+// CHECK: Relocations [
+// CHECK-NEXT: [[BeginDisp:0x[A-F0-9]+]] IMAGE_REL_AMD64_ADDR32NB func
+// CHECK-NEXT: [[EndDisp:0x[A-F0-9]+]] IMAGE_REL_AMD64_ADDR32NB func
+// CHECK-NEXT: [[UnwindDisp:0x[A-F0-9]+]] IMAGE_REL_AMD64_ADDR32NB .xdata
+// CHECK-NEXT: ]
+// CHECK: SectionData (
+// CHECK-NEXT: 0000: FCFFFFFF 05000000 00000000
+// CHECK-NEXT: )
+// CHECK-NEXT: }
+// CHECK-NEXT: ]
+// CHECK: UnwindInformation [
+// CHECK-NEXT: RuntimeFunction {
+// CHECK-NEXT: StartAddress: func {{(\+0x[A-F0-9]+ )?}}([[BeginDisp]])
+// CHECK-NEXT: EndAddress: func {{(\+0x[A-F0-9]+ )?}}([[EndDisp]])
+// CHECK-NEXT: UnwindInfoAddress: .xdata {{(\+0x[A-F0-9]+ )?}}([[UnwindDisp]])
+// CHECK-NEXT: UnwindInfo {
+// CHECK-NEXT: Version: 1
+// CHECK-NEXT: Flags [
+// CHECK-NEXT: ExceptionHandler
+// CHECK-NEXT: ]
+// CHECK-NEXT: PrologSize: 0
+// CHECK-NEXT: FrameRegister: -
+// CHECK-NEXT: FrameOffset: -
+// CHECK-NEXT: UnwindCodeCount: 1
+// CHECK-NEXT: UnwindCodes [
+// CHECK-NEXT: 0x04: ALLOC_SMALL size=24
+// CHECK-NEXT: ]
+// CHECK-NEXT: Handler: __C_specific_handler ([[HandlerDisp]])
+// CHECK-NEXT: }
+// CHECK-NEXT: }
+// CHECK-NEXT: ]
+
+// Generates only one unwind code.
+// Requires padding of the unwind code array.
+ .globl func
+ .def func; .scl 2; .type 32; .endef
+ .seh_proc func
+ subq $24, %rsp
+ .seh_stackalloc 24
+ .seh_handler __C_specific_handler, @except
+ .seh_handlerdata
+ .long 0xcafebabe
+ .text
+ .seh_endprologue
+func:
+ addq $24, %rsp
+ ret
+ .seh_endproc
diff --git a/test/MC/COFF/seh-align3.s b/test/MC/COFF/seh-align3.s
new file mode 100644
index 0000000..238b5de
--- /dev/null
+++ b/test/MC/COFF/seh-align3.s
@@ -0,0 +1,83 @@
+// This test checks the alignment and padding of the unwind info.
+
+// RUN: llvm-mc -triple x86_64-pc-win32 -filetype=obj %s | llvm-readobj -s -sd -sr -u | FileCheck %s
+
+// CHECK: Sections [
+// CHECK: Section {
+// CHECK: Name: .xdata
+// CHECK: RawDataSize: 16
+// CHECK: RelocationCount: 1
+// CHECK: Characteristics [
+// CHECK-NEXT: ALIGN_4BYTES
+// CHECK-NEXT: CNT_INITIALIZED_DATA
+// CHECK-NEXT: MEM_READ
+// CHECK-NEXT: ]
+// CHECK: Relocations [
+// CHECK-NEXT: [[HandlerDisp:0x[A-F0-9]+]] IMAGE_REL_AMD64_ADDR32NB __C_specific_handler
+// CHECK-NEXT: ]
+// CHECK: SectionData (
+// CHECK-NEXT: 0000: 19000200 04D002C0 00000000 BEBAFECA
+// CHECK-NEXT: )
+// CHECK-NEXT: }
+// CHECK-NEXT: Section {
+// CHECK: Name: .pdata
+// CHECK: RawDataSize: 12
+// CHECK: RelocationCount: 3
+// CHECK: Characteristics [
+// CHECK-NEXT: IMAGE_SCN_ALIGN_4BYTES
+// CHECK-NEXT: IMAGE_SCN_CNT_INITIALIZED_DATA
+// CHECK-NEXT: IMAGE_SCN_MEM_READ
+// CHECK-NEXT: ]
+// CHECK: Relocations [
+// CHECK-NEXT: [[BeginDisp:0x[A-F0-9]+]] IMAGE_REL_AMD64_ADDR32NB func
+// CHECK-NEXT: [[EndDisp:0x[A-F0-9]+]] IMAGE_REL_AMD64_ADDR32NB func
+// CHECK-NEXT: [[UnwindDisp:0x[A-F0-9]+]] IMAGE_REL_AMD64_ADDR32NB .xdata
+// CHECK-NEXT: ]
+// CHECK: SectionData (
+// CHECK-NEXT: 0000: FCFFFFFF 05000000 00000000
+// CHECK-NEXT: )
+// CHECK-NEXT: }
+// CHECK-NEXT: ]
+// CHECK: UnwindInformation [
+// CHECK-NEXT: RuntimeFunction {
+// CHECK-NEXT: StartAddress: func {{(\+0x[A-F0-9]+ )?}}([[BeginDisp]])
+// CHECK-NEXT: EndAddress: func {{(\+0x[A-F0-9]+ )?}}([[EndDisp]])
+// CHECK-NEXT: UnwindInfoAddress: .xdata {{(\+0x[A-F0-9]+ )?}}([[UnwindDisp]])
+// CHECK-NEXT: UnwindInfo {
+// CHECK-NEXT: Version: 1
+// CHECK-NEXT: Flags [
+// CHECK-NEXT: ExceptionHandler
+// CHECK-NEXT: TerminateHandler
+// CHECK-NEXT: ]
+// CHECK-NEXT: PrologSize: 0
+// CHECK-NEXT: FrameRegister: -
+// CHECK-NEXT: FrameOffset: -
+// CHECK-NEXT: UnwindCodeCount: 2
+// CHECK-NEXT: UnwindCodes [
+// CHECK-NEXT: 0x04: PUSH_NONVOL reg=R13
+// CHECK-NEXT: 0x02: PUSH_NONVOL reg=R12
+// CHECK-NEXT: ]
+// CHECK-NEXT: Handler: __C_specific_handler ([[HandlerDisp]])
+// CHECK-NEXT: }
+// CHECK-NEXT: }
+// CHECK-NEXT: ]
+
+// Generates two unwind codes.
+// Requires no padding of the unwind code array.
+ .globl func
+ .def func; .scl 2; .type 32; .endef
+ .seh_proc func
+ push %r12
+ .seh_pushreg 12
+ push %r13
+ .seh_pushreg 13
+ .seh_handler __C_specific_handler, @except, @unwind
+ .seh_handlerdata
+ .long 0xcafebabe
+ .text
+ .seh_endprologue
+func:
+ pop %r13
+ pop %r12
+ ret
+ .seh_endproc
--
1.8.0.msysgit.0
-------------- next part --------------
>From e66e56797780eaa052036f90e8105a0d07db2ad3 Mon Sep 17 00:00:00 2001
From: kai <kai at redstar.de>
Date: Wed, 29 May 2013 06:41:03 +0200
Subject: [PATCH 4/5] Emit personality function and Dwarf EH data for Win64
SEH.
Obviously the personality function should be emitted as language handler
instead of the hard coded _GCC_specific_handler. The language specific
data must be placed after the unwind information therefore it must not
be emitted into a separate section.
---
lib/CodeGen/AsmPrinter/Win64Exception.cpp | 12 +++---------
lib/MC/MCObjectFileInfo.cpp | 15 ++++++++++-----
2 files changed, 13 insertions(+), 14 deletions(-)
diff --git a/lib/CodeGen/AsmPrinter/Win64Exception.cpp b/lib/CodeGen/AsmPrinter/Win64Exception.cpp
index 1561012..99d53b9 100644
--- a/lib/CodeGen/AsmPrinter/Win64Exception.cpp
+++ b/lib/CodeGen/AsmPrinter/Win64Exception.cpp
@@ -78,9 +78,9 @@ void Win64Exception::BeginFunction(const MachineFunction *MF) {
if (!shouldEmitPersonality)
return;
- MCSymbol *GCCHandlerSym =
- Asm->GetExternalSymbolSymbol("_GCC_specific_handler");
- Asm->OutStreamer.EmitWin64EHHandler(GCCHandlerSym, true, true);
+ const MCSymbol *PersHandlerSym = TLOF.getCFIPersonalitySymbol(Per, Asm->Mang,
+ MMI);
+ Asm->OutStreamer.EmitWin64EHHandler(PersHandlerSym, true, true);
Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin",
Asm->getFunctionNumber()));
@@ -99,14 +99,8 @@ void Win64Exception::EndFunction() {
MMI->TidyLandingPads();
if (shouldEmitPersonality) {
- const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
- const Function *Per = MMI->getPersonalities()[MMI->getPersonalityIndex()];
- const MCSymbol *Sym = TLOF.getCFIPersonalitySymbol(Per, Asm->Mang, MMI);
-
Asm->OutStreamer.PushSection();
Asm->OutStreamer.EmitWin64EHHandlerData();
- Asm->OutStreamer.EmitValue(MCSymbolRefExpr::Create(Sym, Asm->OutContext),
- 4);
EmitExceptionTable();
Asm->OutStreamer.PopSection();
}
diff --git a/lib/MC/MCObjectFileInfo.cpp b/lib/MC/MCObjectFileInfo.cpp
index 96b62f1..1be20c3 100644
--- a/lib/MC/MCObjectFileInfo.cpp
+++ b/lib/MC/MCObjectFileInfo.cpp
@@ -547,11 +547,16 @@ void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
// though it contains relocatable pointers. In PIC mode, this is probably a
// big runtime hit for C++ apps. Either the contents of the LSDA need to be
// adjusted or this should be a data section.
- LSDASection =
- Ctx->getCOFFSection(".gcc_except_table",
- COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
- COFF::IMAGE_SCN_MEM_READ,
- SectionKind::getReadOnly());
+ if (T.getOS() == Triple::Win32) {
+ // On Windows with SEH, the LSDA is emitted into the .xdata section
+ LSDASection = 0;
+ } else {
+ LSDASection =
+ Ctx->getCOFFSection(".gcc_except_table",
+ COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
+ COFF::IMAGE_SCN_MEM_READ,
+ SectionKind::getReadOnly());
+ }
// Debug info.
DwarfAbbrevSection =
--
1.8.0.msysgit.0
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