[llvm-commits] [llvm] r97078 - in /llvm/trunk/lib/CodeGen/AsmPrinter: DwarfException.cpp DwarfPrinter.cpp DwarfPrinter.h
Bill Wendling
isanbard at gmail.com
Wed Feb 24 15:34:35 PST 2010
Author: void
Date: Wed Feb 24 17:34:35 2010
New Revision: 97078
URL: http://llvm.org/viewvc/llvm-project?rev=97078&view=rev
Log:
LLVM puts padding bytes in the __gcc_except_tab section after the
GCC_except_table label but before the Lexception, which the FDE references.
This causes problems as the FDE does not point to the start of an LSDA chunk.
Use an unnormalized uleb128 for the call-site table length that includes the
padding.
Modified:
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfPrinter.cpp
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfPrinter.h
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp?rev=97078&r1=97077&r2=97078&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfException.cpp Wed Feb 24 17:34:35 2010
@@ -638,18 +638,18 @@
const unsigned LandingPadSize = SizeOfEncodedValue(dwarf::DW_EH_PE_udata4);
bool IsSJLJ = MAI->getExceptionHandlingType() == ExceptionHandling::SjLj;
bool HaveTTData = IsSJLJ ? (!TypeInfos.empty() || !FilterIds.empty()) : true;
- unsigned SizeSites;
+ unsigned CallSiteTableLength;
if (IsSJLJ)
- SizeSites = 0;
+ CallSiteTableLength = 0;
else
- SizeSites = CallSites.size() *
+ CallSiteTableLength = CallSites.size() *
(SiteStartSize + SiteLengthSize + LandingPadSize);
for (unsigned i = 0, e = CallSites.size(); i < e; ++i) {
- SizeSites += MCAsmInfo::getULEB128Size(CallSites[i].Action);
+ CallSiteTableLength += MCAsmInfo::getULEB128Size(CallSites[i].Action);
if (IsSJLJ)
- SizeSites += MCAsmInfo::getULEB128Size(i);
+ CallSiteTableLength += MCAsmInfo::getULEB128Size(i);
}
// Type infos.
@@ -698,7 +698,20 @@
Asm->OutStreamer.SwitchSection(LSDASection);
Asm->EmitAlignment(2, 0, 0, false);
+ // Emit the LSDA.
O << "GCC_except_table" << SubprogramCount << ":\n";
+ EmitLabel("exception", SubprogramCount);
+
+ if (IsSJLJ) {
+ SmallString<16> LSDAName;
+ raw_svector_ostream(LSDAName) << MAI->getPrivateGlobalPrefix() <<
+ "_LSDA_" << Asm->getFunctionNumber();
+ O << LSDAName.str() << ":\n";
+ }
+
+ // Emit the LSDA header.
+ EmitEncodingByte(dwarf::DW_EH_PE_omit, "@LPStart");
+ EmitEncodingByte(TTypeEncoding, "@TType");
// The type infos need to be aligned. GCC does this by inserting padding just
// before the type infos. However, this changes the size of the exception
@@ -707,7 +720,7 @@
// So by increasing the size by inserting padding, you may increase the number
// of bytes used for writing the size. If it increases, say by one byte, then
// you now need to output one less byte of padding to get the type infos
- // aligned. However this decreases the size of the exception table. This
+ // aligned. However this decreases the size of the exception table. This
// changes the value you have to output for the exception table size. Due to
// the variable length encoding, the number of bytes used for writing the
// length may decrease. If so, you then have to increase the amount of
@@ -716,41 +729,30 @@
// We chose another solution: don't output padding inside the table like GCC
// does, instead output it before the table.
unsigned SizeTypes = TypeInfos.size() * TypeFormatSize;
- unsigned TyOffset = sizeof(int8_t) + // Call site format
- MCAsmInfo::getULEB128Size(SizeSites) + // Call site table length
- SizeSites + SizeActions + SizeTypes;
- unsigned TotalSize = sizeof(int8_t) + // LPStart format
- sizeof(int8_t) + // TType format
- (HaveTTData ?
- MCAsmInfo::getULEB128Size(TyOffset) : 0) + // TType base offset
- TyOffset;
+ unsigned CallSiteTableLengthSize =
+ MCAsmInfo::getULEB128Size(CallSiteTableLength);
+ unsigned TTypeBaseOffset =
+ sizeof(int8_t) + // Call site format
+ CallSiteTableLengthSize + // Call site table length size
+ CallSiteTableLength + // Call site table length
+ SizeActions + // Actions size
+ SizeTypes;
+ unsigned TTypeBaseOffsetSize = MCAsmInfo::getULEB128Size(TTypeBaseOffset);
+ unsigned TotalSize =
+ sizeof(int8_t) + // LPStart format
+ sizeof(int8_t) + // TType format
+ (HaveTTData ? TTypeBaseOffsetSize : 0) + // TType base offset size
+ TTypeBaseOffset; // TType base offset
unsigned SizeAlign = (4 - TotalSize) & 3;
- for (unsigned i = 0; i != SizeAlign; ++i) {
- Asm->EmitInt8(0);
- EOL("Padding");
- }
-
- EmitLabel("exception", SubprogramCount);
-
- if (IsSJLJ) {
- SmallString<16> LSDAName;
- raw_svector_ostream(LSDAName) << MAI->getPrivateGlobalPrefix() <<
- "_LSDA_" << Asm->getFunctionNumber();
- O << LSDAName.str() << ":\n";
- }
-
- // Emit the header.
- EmitEncodingByte(dwarf::DW_EH_PE_omit, "@LPStart");
- EmitEncodingByte(TTypeEncoding, "@TType");
-
if (HaveTTData)
- EmitULEB128(TyOffset, "@TType base offset");
+ // Pad here for alignment.
+ EmitULEB128(TTypeBaseOffset + SizeAlign, "@TType base offset");
// SjLj Exception handling
if (IsSJLJ) {
EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");
- EmitULEB128(SizeSites, "Call site table length");
+ EmitULEB128(CallSiteTableLength, "Call site table length", SizeAlign);
// Emit the landing pad site information.
unsigned idx = 0;
@@ -791,7 +793,7 @@
// Emit the landing pad call site table.
EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");
- EmitULEB128(SizeSites, "Call site table length");
+ EmitULEB128(CallSiteTableLength, "Call site table length", SizeAlign);
for (SmallVectorImpl<CallSiteEntry>::const_iterator
I = CallSites.begin(), E = CallSites.end(); I != E; ++I) {
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfPrinter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfPrinter.cpp?rev=97078&r1=97077&r2=97078&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfPrinter.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfPrinter.cpp Wed Feb 24 17:34:35 2010
@@ -159,29 +159,37 @@
Value >>= 7;
IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0;
if (IsMore) Byte |= 0x80;
-
Asm->OutStreamer.EmitIntValue(Byte, 1, /*addrspace*/0);
} while (IsMore);
}
/// EmitULEB128 - emit the specified signed leb128 value.
-void DwarfPrinter::EmitULEB128(unsigned Value, const char *Desc) const {
+void DwarfPrinter::EmitULEB128(unsigned Value, const char *Desc,
+ unsigned PadTo) const {
if (Asm->VerboseAsm && Desc)
Asm->OutStreamer.AddComment(Desc);
- if (MAI->hasLEB128()) {
+ if (MAI->hasLEB128() && PadTo == 0) {
O << "\t.uleb128\t" << Value;
Asm->OutStreamer.AddBlankLine();
return;
}
- // If we don't have .uleb128, emit as .bytes.
+ // If we don't have .uleb128 or we want to emit padding, emit as .bytes.
do {
unsigned char Byte = static_cast<unsigned char>(Value & 0x7f);
Value >>= 7;
- if (Value) Byte |= 0x80;
+ if (Value || PadTo != 0) Byte |= 0x80;
Asm->OutStreamer.EmitIntValue(Byte, 1, /*addrspace*/0);
} while (Value);
+
+ if (PadTo)
+ while (PadTo--) {
+ unsigned char Byte = (PadTo ? 0x80 : 0x00);
+ if (Asm->VerboseAsm)
+ Asm->OutStreamer.AddComment("Padding");
+ Asm->OutStreamer.EmitIntValue(Byte, 1, /*addrspace*/0);
+ }
}
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfPrinter.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfPrinter.h?rev=97078&r1=97077&r2=97078&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfPrinter.h (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfPrinter.h Wed Feb 24 17:34:35 2010
@@ -111,7 +111,8 @@
void EmitSLEB128(int Value, const char *Desc) const;
/// EmitULEB128 - emit the specified unsigned leb128 value.
- void EmitULEB128(unsigned Value, const char *Desc = 0) const;
+ void EmitULEB128(unsigned Value, const char *Desc = 0,
+ unsigned PadTo = 0) const;
/// PrintLabelName - Print label name in form used by Dwarf writer.
More information about the llvm-commits
mailing list