[llvm] [llvm] Win x64 Unwind V2 2/n: Support dumping UOP_Epilog (PR #110338)
Daniel Paoliello via llvm-commits
llvm-commits at lists.llvm.org
Fri Sep 27 16:14:50 PDT 2024
https://github.com/dpaoliello created https://github.com/llvm/llvm-project/pull/110338
Adds support to objdump and readobj for reading the `UOP_Epilog` entries of Windows x64 unwind v2.
`UOP_Epilog` has a weird format:
The first `UOP_Epilog` in the unwind data is the "header":
* The least-significant bit of `OpInfo` is the "At End" flag, which signifies that there is an epilog at the very end of the associated function.
* `CodeOffset` is the length each epilog described by the current unwind information (all epilogs have the same length).
Any subsequent `UOP_Epilog` represents another epilog for the current function, where `OpInfo` and `CodeOffset` are combined to a 12-bit value which is the offset of the beginning of the epilog from the end of the current function. If the offset is 0, then this entry is actually padding and can be ignored.
>From f23540ffd9e51323fb3f386cce35f1644e9e3e8f Mon Sep 17 00:00:00 2001
From: Daniel Paoliello <danpao at microsoft.com>
Date: Fri, 27 Sep 2024 16:05:35 -0700
Subject: [PATCH] [llvm] Win x64 Unwind V2 2/n: Support dumping UOP_Epilog
---
llvm/tools/llvm-objdump/COFFDump.cpp | 25 ++++++++++++++++++---
llvm/tools/llvm-readobj/Win64EHDumper.cpp | 27 +++++++++++++++++++++--
llvm/tools/llvm-readobj/Win64EHDumper.h | 3 ++-
3 files changed, 49 insertions(+), 6 deletions(-)
diff --git a/llvm/tools/llvm-objdump/COFFDump.cpp b/llvm/tools/llvm-objdump/COFFDump.cpp
index 71697fa01e627d..97901ebf9851d8 100644
--- a/llvm/tools/llvm-objdump/COFFDump.cpp
+++ b/llvm/tools/llvm-objdump/COFFDump.cpp
@@ -240,10 +240,10 @@ static unsigned getNumUsedSlots(const UnwindCode &UnwindCode) {
case UOP_AllocSmall:
case UOP_SetFPReg:
case UOP_PushMachFrame:
+ case UOP_Epilog:
return 1;
case UOP_SaveNonVol:
case UOP_SaveXMM128:
- case UOP_Epilog:
return 2;
case UOP_SaveNonVolBig:
case UOP_SaveXMM128Big:
@@ -257,7 +257,7 @@ static unsigned getNumUsedSlots(const UnwindCode &UnwindCode) {
// Prints one unwind code. Because an unwind code can occupy up to 3 slots in
// the unwind codes array, this function requires that the correct number of
// slots is provided.
-static void printUnwindCode(ArrayRef<UnwindCode> UCs) {
+static void printUnwindCode(ArrayRef<UnwindCode> UCs, bool &SeenFirstEpilog) {
assert(UCs.size() >= getNumUsedSlots(UCs[0]));
outs() << format(" 0x%02x: ", unsigned(UCs[0].u.CodeOffset))
<< getUnwindCodeTypeName(UCs[0].getUnwindOp());
@@ -301,11 +301,30 @@ static void printUnwindCode(ArrayRef<UnwindCode> UCs) {
outs() << " " << (UCs[0].getOpInfo() ? "w/o" : "w")
<< " error code";
break;
+
+ case UOP_Epilog:
+ if (SeenFirstEpilog) {
+ uint32_t Offset = (UCs[0].getOpInfo() << 8) |
+ static_cast<uint32_t>(UCs[0].u.CodeOffset);
+ if (Offset == 0) {
+ outs() << " padding";
+ } else {
+ outs() << " offset=" << format("0x%X", Offset);
+ }
+ } else {
+ SeenFirstEpilog = true;
+ bool AtEnd = (UCs[0].getOpInfo() & 0x1) != 0;
+ uint32_t Length = UCs[0].u.CodeOffset;
+ outs() << " atend=" << (AtEnd ? "yes" : "no")
+ << ", length=" << format("0x%X", Length);
+ }
+ break;
}
outs() << "\n";
}
static void printAllUnwindCodes(ArrayRef<UnwindCode> UCs) {
+ bool SeenFirstEpilog = false;
for (const UnwindCode *I = UCs.begin(), *E = UCs.end(); I < E; ) {
unsigned UsedSlots = getNumUsedSlots(*I);
if (UsedSlots > UCs.size()) {
@@ -316,7 +335,7 @@ static void printAllUnwindCodes(ArrayRef<UnwindCode> UCs) {
<< " remaining in buffer";
return ;
}
- printUnwindCode(ArrayRef(I, E));
+ printUnwindCode(ArrayRef(I, E), SeenFirstEpilog);
I += UsedSlots;
}
}
diff --git a/llvm/tools/llvm-readobj/Win64EHDumper.cpp b/llvm/tools/llvm-readobj/Win64EHDumper.cpp
index e4bd772191514a..ee043c9d0d10a1 100644
--- a/llvm/tools/llvm-readobj/Win64EHDumper.cpp
+++ b/llvm/tools/llvm-readobj/Win64EHDumper.cpp
@@ -65,6 +65,8 @@ static StringRef getUnwindCodeTypeName(uint8_t Code) {
case UOP_SaveXMM128: return "SAVE_XMM128";
case UOP_SaveXMM128Big: return "SAVE_XMM128_FAR";
case UOP_PushMachFrame: return "PUSH_MACHFRAME";
+ case UOP_Epilog:
+ return "EPILOG";
}
}
@@ -99,6 +101,7 @@ static unsigned getNumUsedSlots(const UnwindCode &UnwindCode) {
case UOP_AllocSmall:
case UOP_SetFPReg:
case UOP_PushMachFrame:
+ case UOP_Epilog:
return 1;
case UOP_SaveNonVol:
case UOP_SaveXMM128:
@@ -254,7 +257,8 @@ void Dumper::printRuntimeFunctionEntry(const Context &Ctx,
// Prints one unwind code. Because an unwind code can occupy up to 3 slots in
// the unwind codes array, this function requires that the correct number of
// slots is provided.
-void Dumper::printUnwindCode(const UnwindInfo& UI, ArrayRef<UnwindCode> UC) {
+void Dumper::printUnwindCode(const UnwindInfo &UI, ArrayRef<UnwindCode> UC,
+ bool &SeenFirstEpilog) {
assert(UC.size() >= getNumUsedSlots(UC[0]));
SW.startLine() << format("0x%02X: ", unsigned(UC[0].u.CodeOffset))
@@ -306,6 +310,24 @@ void Dumper::printUnwindCode(const UnwindInfo& UI, ArrayRef<UnwindCode> UC) {
case UOP_PushMachFrame:
OS << " errcode=" << (UC[0].getOpInfo() == 0 ? "no" : "yes");
break;
+
+ case UOP_Epilog:
+ if (SeenFirstEpilog) {
+ uint32_t Offset =
+ (UC[0].getOpInfo() << 8) | static_cast<uint32_t>(UC[0].u.CodeOffset);
+ if (Offset == 0) {
+ OS << " padding";
+ } else {
+ OS << " offset=" << format("0x%X", Offset);
+ }
+ } else {
+ SeenFirstEpilog = true;
+ bool AtEnd = (UC[0].getOpInfo() & 0x1) != 0;
+ uint32_t Length = UC[0].u.CodeOffset;
+ OS << " atend=" << (AtEnd ? "yes" : "no")
+ << ", length=" << format("0x%X", Length);
+ }
+ break;
}
OS << "\n";
@@ -330,6 +352,7 @@ void Dumper::printUnwindInfo(const Context &Ctx, const coff_section *Section,
{
ListScope UCS(SW, "UnwindCodes");
ArrayRef<UnwindCode> UC(&UI.UnwindCodes[0], UI.NumCodes);
+ bool SeenFirstEpilog = false;
for (const UnwindCode *UCI = UC.begin(), *UCE = UC.end(); UCI < UCE; ++UCI) {
unsigned UsedSlots = getNumUsedSlots(*UCI);
if (UsedSlots > UC.size()) {
@@ -337,7 +360,7 @@ void Dumper::printUnwindInfo(const Context &Ctx, const coff_section *Section,
return;
}
- printUnwindCode(UI, ArrayRef(UCI, UCE));
+ printUnwindCode(UI, ArrayRef(UCI, UCE), SeenFirstEpilog);
UCI = UCI + UsedSlots - 1;
}
}
diff --git a/llvm/tools/llvm-readobj/Win64EHDumper.h b/llvm/tools/llvm-readobj/Win64EHDumper.h
index 97458c916bec6f..a23d30be7a113d 100644
--- a/llvm/tools/llvm-readobj/Win64EHDumper.h
+++ b/llvm/tools/llvm-readobj/Win64EHDumper.h
@@ -44,7 +44,8 @@ class Dumper {
const object::coff_section *Section,
uint64_t SectionOffset,
const RuntimeFunction &RF);
- void printUnwindCode(const UnwindInfo& UI, ArrayRef<UnwindCode> UC);
+ void printUnwindCode(const UnwindInfo &UI, ArrayRef<UnwindCode> UC,
+ bool &SeenFirstEpilog);
void printUnwindInfo(const Context &Ctx, const object::coff_section *Section,
off_t Offset, const UnwindInfo &UI);
void printRuntimeFunction(const Context &Ctx,
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