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-rw-r--r--lib/CodeGen/AsmPrinter/EHStreamer.cpp152
1 files changed, 47 insertions, 105 deletions
diff --git a/lib/CodeGen/AsmPrinter/EHStreamer.cpp b/lib/CodeGen/AsmPrinter/EHStreamer.cpp
index 3cdab57bca70..65de9d7e65a4 100644
--- a/lib/CodeGen/AsmPrinter/EHStreamer.cpp
+++ b/lib/CodeGen/AsmPrinter/EHStreamer.cpp
@@ -20,7 +20,6 @@
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineOperand.h"
-#include "llvm/CodeGen/TargetLoweringObjectFile.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/MC/MCAsmInfo.h"
@@ -30,6 +29,7 @@
#include "llvm/MC/MCTargetOptions.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/LEB128.h"
+#include "llvm/Target/TargetLoweringObjectFile.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
@@ -58,10 +58,10 @@ unsigned EHStreamer::sharedTypeIDs(const LandingPadInfo *L,
/// Compute the actions table and gather the first action index for each landing
/// pad site.
-unsigned EHStreamer::
-computeActionsTable(const SmallVectorImpl<const LandingPadInfo*> &LandingPads,
- SmallVectorImpl<ActionEntry> &Actions,
- SmallVectorImpl<unsigned> &FirstActions) {
+void EHStreamer::computeActionsTable(
+ const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
+ SmallVectorImpl<ActionEntry> &Actions,
+ SmallVectorImpl<unsigned> &FirstActions) {
// The action table follows the call-site table in the LSDA. The individual
// records are of two types:
//
@@ -149,7 +149,7 @@ computeActionsTable(const SmallVectorImpl<const LandingPadInfo*> &LandingPads,
FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
} // else identical - re-use previous FirstAction
- // Information used when created the call-site table. The action record
+ // Information used when creating the call-site table. The action record
// field of the call site record is the offset of the first associated
// action record, relative to the start of the actions table. This value is
// biased by 1 (1 indicating the start of the actions table), and 0
@@ -161,8 +161,6 @@ computeActionsTable(const SmallVectorImpl<const LandingPadInfo*> &LandingPads,
PrevLPI = LPI;
}
-
- return SizeActions;
}
/// Return `true' if this is a call to a function marked `nounwind'. Return
@@ -361,55 +359,33 @@ void EHStreamer::emitExceptionTable() {
LandingPads.push_back(&PadInfos[i]);
// Order landing pads lexicographically by type id.
- std::sort(LandingPads.begin(), LandingPads.end(),
- [](const LandingPadInfo *L,
- const LandingPadInfo *R) { return L->TypeIds < R->TypeIds; });
+ llvm::sort(LandingPads.begin(), LandingPads.end(),
+ [](const LandingPadInfo *L,
+ const LandingPadInfo *R) { return L->TypeIds < R->TypeIds; });
// Compute the actions table and gather the first action index for each
// landing pad site.
SmallVector<ActionEntry, 32> Actions;
SmallVector<unsigned, 64> FirstActions;
- unsigned SizeActions =
- computeActionsTable(LandingPads, Actions, FirstActions);
+ computeActionsTable(LandingPads, Actions, FirstActions);
// Compute the call-site table.
SmallVector<CallSiteEntry, 64> CallSites;
computeCallSiteTable(CallSites, LandingPads, FirstActions);
- // Final tallies.
-
- // Call sites.
bool IsSJLJ = Asm->MAI->getExceptionHandlingType() == ExceptionHandling::SjLj;
- bool HaveTTData = IsSJLJ ? (!TypeInfos.empty() || !FilterIds.empty()) : true;
-
- unsigned CallSiteTableLength;
- if (IsSJLJ)
- CallSiteTableLength = 0;
- else {
- unsigned SiteStartSize = 4; // dwarf::DW_EH_PE_udata4
- unsigned SiteLengthSize = 4; // dwarf::DW_EH_PE_udata4
- unsigned LandingPadSize = 4; // dwarf::DW_EH_PE_udata4
- CallSiteTableLength =
- CallSites.size() * (SiteStartSize + SiteLengthSize + LandingPadSize);
- }
-
- for (unsigned i = 0, e = CallSites.size(); i < e; ++i) {
- CallSiteTableLength += getULEB128Size(CallSites[i].Action);
- if (IsSJLJ)
- CallSiteTableLength += getULEB128Size(i);
- }
+ unsigned CallSiteEncoding =
+ IsSJLJ ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_uleb128;
+ bool HaveTTData = !TypeInfos.empty() || !FilterIds.empty();
// Type infos.
MCSection *LSDASection = Asm->getObjFileLowering().getLSDASection();
unsigned TTypeEncoding;
- unsigned TypeFormatSize;
if (!HaveTTData) {
- // For SjLj exceptions, if there is no TypeInfo, then we just explicitly say
- // that we're omitting that bit.
+ // If there is no TypeInfo, then we just explicitly say that we're omitting
+ // that bit.
TTypeEncoding = dwarf::DW_EH_PE_omit;
- // dwarf::DW_EH_PE_absptr
- TypeFormatSize = Asm->getDataLayout().getPointerSize();
} else {
// Okay, we have actual filters or typeinfos to emit. As such, we need to
// pick a type encoding for them. We're about to emit a list of pointers to
@@ -439,7 +415,6 @@ void EHStreamer::emitExceptionTable() {
// in target-independent code.
//
TTypeEncoding = Asm->getObjFileLowering().getTTypeEncoding();
- TypeFormatSize = Asm->GetSizeOfEncodedValue(TTypeEncoding);
}
// Begin the exception table.
@@ -460,64 +435,35 @@ void EHStreamer::emitExceptionTable() {
Asm->EmitEncodingByte(dwarf::DW_EH_PE_omit, "@LPStart");
Asm->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
- // table, so you need to take this into account when you output the exception
- // table size. However, the size is output using a variable length encoding.
- // 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
- // 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
- // padding. And so on. If you look carefully at the GCC code you will see that
- // it indeed does this in a loop, going on and on until the values stabilize.
- // 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 CallSiteTableLengthSize = 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 = 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 PadBytes = (4 - TotalSize) & 3;
-
+ MCSymbol *TTBaseLabel = nullptr;
if (HaveTTData) {
- // Account for any extra padding that will be added to the call site table
- // length.
- Asm->EmitPaddedULEB128(TTypeBaseOffset, TTypeBaseOffsetSize + PadBytes,
- "@TType base offset");
- PadBytes = 0;
+ // N.B.: There is a dependency loop between the size of the TTBase uleb128
+ // here and the amount of padding before the aligned type table. The
+ // assembler must sometimes pad this uleb128 or insert extra padding before
+ // the type table. See PR35809 or GNU as bug 4029.
+ MCSymbol *TTBaseRefLabel = Asm->createTempSymbol("ttbaseref");
+ TTBaseLabel = Asm->createTempSymbol("ttbase");
+ Asm->EmitLabelDifferenceAsULEB128(TTBaseLabel, TTBaseRefLabel);
+ Asm->OutStreamer->EmitLabel(TTBaseRefLabel);
}
bool VerboseAsm = Asm->OutStreamer->isVerboseAsm();
+ // Emit the landing pad call site table.
+ MCSymbol *CstBeginLabel = Asm->createTempSymbol("cst_begin");
+ MCSymbol *CstEndLabel = Asm->createTempSymbol("cst_end");
+ Asm->EmitEncodingByte(CallSiteEncoding, "Call site");
+ Asm->EmitLabelDifferenceAsULEB128(CstEndLabel, CstBeginLabel);
+ Asm->OutStreamer->EmitLabel(CstBeginLabel);
+
// SjLj Exception handling
if (IsSJLJ) {
- Asm->EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");
-
- // Add extra padding if it wasn't added to the TType base offset.
- Asm->EmitPaddedULEB128(CallSiteTableLength,
- CallSiteTableLengthSize + PadBytes,
- "Call site table length");
-
- // Emit the landing pad site information.
unsigned idx = 0;
for (SmallVectorImpl<CallSiteEntry>::const_iterator
I = CallSites.begin(), E = CallSites.end(); I != E; ++I, ++idx) {
const CallSiteEntry &S = *I;
- // Offset of the landing pad, counted in 16-byte bundles relative to the
- // @LPStart address.
+ // Index of the call site entry.
if (VerboseAsm) {
Asm->OutStreamer->AddComment(">> Call Site " + Twine(idx) + " <<");
Asm->OutStreamer->AddComment(" On exception at call site "+Twine(idx));
@@ -557,14 +503,6 @@ void EHStreamer::emitExceptionTable() {
// A missing entry in the call-site table indicates that a call is not
// supposed to throw.
- // Emit the landing pad call site table.
- Asm->EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");
-
- // Add extra padding if it wasn't added to the TType base offset.
- Asm->EmitPaddedULEB128(CallSiteTableLength,
- CallSiteTableLengthSize + PadBytes,
- "Call site table length");
-
unsigned Entry = 0;
for (SmallVectorImpl<CallSiteEntry>::const_iterator
I = CallSites.begin(), E = CallSites.end(); I != E; ++I) {
@@ -579,29 +517,27 @@ void EHStreamer::emitExceptionTable() {
if (!EndLabel)
EndLabel = Asm->getFunctionEnd();
- // Offset of the call site relative to the previous call site, counted in
- // number of 16-byte bundles. The first call site is counted relative to
- // the start of the procedure fragment.
+ // Offset of the call site relative to the start of the procedure.
if (VerboseAsm)
Asm->OutStreamer->AddComment(">> Call Site " + Twine(++Entry) + " <<");
- Asm->EmitLabelDifference(BeginLabel, EHFuncBeginSym, 4);
+ Asm->EmitLabelDifferenceAsULEB128(BeginLabel, EHFuncBeginSym);
if (VerboseAsm)
Asm->OutStreamer->AddComment(Twine(" Call between ") +
BeginLabel->getName() + " and " +
EndLabel->getName());
- Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
+ Asm->EmitLabelDifferenceAsULEB128(EndLabel, BeginLabel);
- // Offset of the landing pad, counted in 16-byte bundles relative to the
- // @LPStart address.
+ // Offset of the landing pad relative to the start of the procedure.
if (!S.LPad) {
if (VerboseAsm)
Asm->OutStreamer->AddComment(" has no landing pad");
- Asm->OutStreamer->EmitIntValue(0, 4/*size*/);
+ Asm->EmitULEB128(0);
} else {
if (VerboseAsm)
Asm->OutStreamer->AddComment(Twine(" jumps to ") +
S.LPad->LandingPadLabel->getName());
- Asm->EmitLabelDifference(S.LPad->LandingPadLabel, EHFuncBeginSym, 4);
+ Asm->EmitLabelDifferenceAsULEB128(S.LPad->LandingPadLabel,
+ EHFuncBeginSym);
}
// Offset of the first associated action record, relative to the start of
@@ -617,6 +553,7 @@ void EHStreamer::emitExceptionTable() {
Asm->EmitULEB128(S.Action);
}
}
+ Asm->OutStreamer->EmitLabel(CstEndLabel);
// Emit the Action Table.
int Entry = 0;
@@ -660,12 +597,15 @@ void EHStreamer::emitExceptionTable() {
Asm->EmitSLEB128(Action.NextAction);
}
- emitTypeInfos(TTypeEncoding);
+ if (HaveTTData) {
+ Asm->EmitAlignment(2);
+ emitTypeInfos(TTypeEncoding, TTBaseLabel);
+ }
Asm->EmitAlignment(2);
}
-void EHStreamer::emitTypeInfos(unsigned TTypeEncoding) {
+void EHStreamer::emitTypeInfos(unsigned TTypeEncoding, MCSymbol *TTBaseLabel) {
const MachineFunction *MF = Asm->MF;
const std::vector<const GlobalValue *> &TypeInfos = MF->getTypeInfos();
const std::vector<unsigned> &FilterIds = MF->getFilterIds();
@@ -687,6 +627,8 @@ void EHStreamer::emitTypeInfos(unsigned TTypeEncoding) {
Asm->EmitTTypeReference(GV, TTypeEncoding);
}
+ Asm->OutStreamer->EmitLabel(TTBaseLabel);
+
// Emit the Exception Specifications.
if (VerboseAsm && !FilterIds.empty()) {
Asm->OutStreamer->AddComment(">> Filter TypeInfos <<");
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-09 13:05:14 +0000