[llvm-branch-commits] [llvm-branch] r351452 - Merging r351421:
Hans Wennborg via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Thu Jan 17 07:39:31 PST 2019
Author: hans
Date: Thu Jan 17 07:39:31 2019
New Revision: 351452
URL: http://llvm.org/viewvc/llvm-project?rev=351452&view=rev
Log:
Merging r351421:
------------------------------------------------------------------------
r351421 | ssijaric | 2019-01-17 10:45:17 +0100 (Thu, 17 Jan 2019) | 12 lines
[ARM64][Windows] Share unwind codes between epilogues
There are cases where we have multiple epilogues that have the exact same unwind
code sequence. In that case, the epilogues can share the same unwind codes in
the .xdata section. This should get us past the assert "SEH unwind data
splitting not yet implemented" in many cases.
We still need to add support for generating multiple .pdata/.xdata sections for
those functions that need to be split into fragments.
Differential Revision: https://reviews.llvm.org/D56813
------------------------------------------------------------------------
Added:
llvm/branches/release_80/test/CodeGen/AArch64/wineh8.mir
- copied unchanged from r351421, llvm/trunk/test/CodeGen/AArch64/wineh8.mir
Modified:
llvm/branches/release_80/ (props changed)
llvm/branches/release_80/lib/MC/MCWin64EH.cpp
llvm/branches/release_80/test/CodeGen/AArch64/wineh4.mir
Propchange: llvm/branches/release_80/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Thu Jan 17 07:39:31 2019
@@ -1,3 +1,3 @@
/llvm/branches/Apple/Pertwee:110850,110961
/llvm/branches/type-system-rewrite:133420-134817
-/llvm/trunk:155241,351344-351345,351349,351351,351370,351381,351436
+/llvm/trunk:155241,351344-351345,351349,351351,351370,351381,351421,351436
Modified: llvm/branches/release_80/lib/MC/MCWin64EH.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_80/lib/MC/MCWin64EH.cpp?rev=351452&r1=351451&r2=351452&view=diff
==============================================================================
--- llvm/branches/release_80/lib/MC/MCWin64EH.cpp (original)
+++ llvm/branches/release_80/lib/MC/MCWin64EH.cpp Thu Jan 17 07:39:31 2019
@@ -453,6 +453,38 @@ static void ARM64EmitUnwindCode(MCStream
}
}
+// Returns the epilog symbol of an epilog with the exact same unwind code
+// sequence, if it exists. Otherwise, returns nulltpr.
+// EpilogInstrs - Unwind codes for the current epilog.
+// Epilogs - Epilogs that potentialy match the current epilog.
+static MCSymbol*
+FindMatchingEpilog(const std::vector<WinEH::Instruction>& EpilogInstrs,
+ const std::vector<MCSymbol *>& Epilogs,
+ const WinEH::FrameInfo *info) {
+ for (auto *EpilogStart : Epilogs) {
+ auto InstrsIter = info->EpilogMap.find(EpilogStart);
+ assert(InstrsIter != info->EpilogMap.end() &&
+ "Epilog not found in EpilogMap");
+ const auto &Instrs = InstrsIter->second;
+
+ if (Instrs.size() != EpilogInstrs.size())
+ continue;
+
+ bool Match = true;
+ for (unsigned i = 0; i < Instrs.size(); ++i)
+ if (Instrs[i].Operation != EpilogInstrs[i].Operation ||
+ Instrs[i].Offset != EpilogInstrs[i].Offset ||
+ Instrs[i].Register != EpilogInstrs[i].Register) {
+ Match = false;
+ break;
+ }
+
+ if (Match)
+ return EpilogStart;
+ }
+ return nullptr;
+}
+
// Populate the .xdata section. The format of .xdata on ARM64 is documented at
// https://docs.microsoft.com/en-us/cpp/build/arm64-exception-handling
static void ARM64EmitUnwindInfo(MCStreamer &streamer, WinEH::FrameInfo *info) {
@@ -477,12 +509,29 @@ static void ARM64EmitUnwindInfo(MCStream
// Process epilogs.
MapVector<MCSymbol *, uint32_t> EpilogInfo;
+ // Epilogs processed so far.
+ std::vector<MCSymbol *> AddedEpilogs;
+
for (auto &I : info->EpilogMap) {
MCSymbol *EpilogStart = I.first;
auto &EpilogInstrs = I.second;
uint32_t CodeBytes = ARM64CountOfUnwindCodes(EpilogInstrs);
- EpilogInfo[EpilogStart] = TotalCodeBytes;
- TotalCodeBytes += CodeBytes;
+
+ uint32_t NumUnwindCodes = EpilogInstrs.size();
+ MCSymbol* MatchingEpilog =
+ FindMatchingEpilog(EpilogInstrs, AddedEpilogs, info);
+ if (MatchingEpilog) {
+ assert(EpilogInfo.find(MatchingEpilog) != EpilogInfo.end() &&
+ "Duplicate epilog not found");
+ EpilogInfo[EpilogStart] = EpilogInfo[MatchingEpilog];
+ // Clear the unwind codes in the EpilogMap, so that they don't get output
+ // in the logic below.
+ EpilogInstrs.clear();
+ } else {
+ EpilogInfo[EpilogStart] = TotalCodeBytes;
+ TotalCodeBytes += CodeBytes;
+ AddedEpilogs.push_back(EpilogStart);
+ }
}
// Code Words, Epilog count, E, X, Vers, Function Length
Modified: llvm/branches/release_80/test/CodeGen/AArch64/wineh4.mir
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_80/test/CodeGen/AArch64/wineh4.mir?rev=351452&r1=351451&r2=351452&view=diff
==============================================================================
--- llvm/branches/release_80/test/CodeGen/AArch64/wineh4.mir (original)
+++ llvm/branches/release_80/test/CodeGen/AArch64/wineh4.mir Thu Jan 17 07:39:31 2019
@@ -1,7 +1,7 @@
# RUN: llc -o - %s -mtriple=aarch64-windows -start-after=prologepilog \
# RUN: -disable-branch-fold -filetype=obj \
# RUN: | llvm-readobj -unwind | FileCheck %s
-# Check that multiple epilgoues are correctly placed in .xdata.
+# Check that identical multiple epilgoues are correctly shared in .xdata.
# CHECK: ExceptionData {
# CHECK-NEXT: FunctionLength: 164
@@ -9,7 +9,7 @@
# CHECK-NEXT: ExceptionData: No
# CHECK-NEXT: EpiloguePacked: No
# CHECK-NEXT: EpilogueScopes: 2
-# CHECK-NEXT: ByteCodeLength: 48
+# CHECK-NEXT: ByteCodeLength: 32
# CHECK-NEXT: Prologue [
# CHECK-NEXT: 0xc80c ; stp x19, x20, [sp, #96]
# CHECK-NEXT: 0xc88a ; stp x21, x22, [sp, #80]
@@ -37,7 +37,7 @@
# CHECK-NEXT: }
# CHECK-NEXT: EpilogueScope {
# CHECK-NEXT: StartOffset: 33
-# CHECK-NEXT: EpilogueStartIndex: 30
+# CHECK-NEXT: EpilogueStartIndex: 15
# CHECK-NEXT: Opcodes [
# CHECK-NEXT: 0xc80c ; ldp x19, x20, [sp, #96]
# CHECK-NEXT: 0xc88a ; ldp x21, x22, [sp, #80]
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