[llvm] cd953e4 - [JITLink][COFF] Don't dead strip seh frame of exported function.
Sunho Kim via llvm-commits
llvm-commits at lists.llvm.org
Mon Jul 25 21:04:40 PDT 2022
Author: Sunho Kim
Date: 2022-07-26T13:04:12+09:00
New Revision: cd953e4ffcfe63ce9133ff7037a2c54aeb9b7421
URL: https://github.com/llvm/llvm-project/commit/cd953e4ffcfe63ce9133ff7037a2c54aeb9b7421
DIFF: https://github.com/llvm/llvm-project/commit/cd953e4ffcfe63ce9133ff7037a2c54aeb9b7421.diff
LOG: [JITLink][COFF] Don't dead strip seh frame of exported function.
Adds keep-alive edges to pdata section to prevent dead strip of block when its parent function is alive.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D129945
Added:
llvm/lib/ExecutionEngine/JITLink/SEHFrameSupport.h
llvm/test/ExecutionEngine/JITLink/X86/COFF_pdata_no_strip.s
llvm/test/ExecutionEngine/JITLink/X86/COFF_pdata_strip.s
Modified:
llvm/lib/ExecutionEngine/JITLink/COFF_x86_64.cpp
Removed:
################################################################################
diff --git a/llvm/lib/ExecutionEngine/JITLink/COFF_x86_64.cpp b/llvm/lib/ExecutionEngine/JITLink/COFF_x86_64.cpp
index 2276a10616fd..e2040dc95acc 100644
--- a/llvm/lib/ExecutionEngine/JITLink/COFF_x86_64.cpp
+++ b/llvm/lib/ExecutionEngine/JITLink/COFF_x86_64.cpp
@@ -12,8 +12,8 @@
#include "llvm/ExecutionEngine/JITLink/COFF_x86_64.h"
#include "COFFLinkGraphBuilder.h"
-#include "EHFrameSupportImpl.h"
#include "JITLinkGeneric.h"
+#include "SEHFrameSupport.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/ExecutionEngine/JITLink/x86_64.h"
#include "llvm/Object/COFF.h"
@@ -239,9 +239,10 @@ void link_COFF_x86_64(std::unique_ptr<LinkGraph> G,
const Triple &TT = G->getTargetTriple();
if (Ctx->shouldAddDefaultTargetPasses(TT)) {
// Add a mark-live pass.
- if (auto MarkLive = Ctx->getMarkLivePass(TT))
+ if (auto MarkLive = Ctx->getMarkLivePass(TT)) {
Config.PrePrunePasses.push_back(std::move(MarkLive));
- else
+ Config.PrePrunePasses.push_back(SEHFrameKeepAlivePass(".pdata"));
+ } else
Config.PrePrunePasses.push_back(markAllSymbolsLive);
// Add COFF edge lowering passes.
diff --git a/llvm/lib/ExecutionEngine/JITLink/SEHFrameSupport.h b/llvm/lib/ExecutionEngine/JITLink/SEHFrameSupport.h
new file mode 100644
index 000000000000..f7689e4e4043
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/JITLink/SEHFrameSupport.h
@@ -0,0 +1,61 @@
+//===------- SEHFrameSupport.h - JITLink seh-frame utils --------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// SEHFrame utils for JITLink.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_EXECUTIONENGINE_JITLINK_SEHFRAMESUPPORT_H
+#define LLVM_EXECUTIONENGINE_JITLINK_SEHFRAMESUPPORT_H
+
+#include "llvm/ADT/Triple.h"
+#include "llvm/ExecutionEngine/JITLink/JITLink.h"
+#include "llvm/ExecutionEngine/JITSymbol.h"
+#include "llvm/Support/Error.h"
+
+namespace llvm {
+namespace jitlink {
+/// This pass adds keep-alive edge from SEH frame sections
+/// to the parent function content block.
+class SEHFrameKeepAlivePass {
+public:
+ SEHFrameKeepAlivePass(StringRef SEHFrameSectionName)
+ : SEHFrameSectionName(SEHFrameSectionName) {}
+
+ Error operator()(LinkGraph &G) {
+ auto *S = G.findSectionByName(SEHFrameSectionName);
+ if (!S)
+ return Error::success();
+
+ // Simply consider every block pointed by seh frame block as parants.
+ // This adds some unnecessary keep-alive edges to unwind info blocks,
+ // (xdata) but these blocks are usually dead by default, so they wouldn't
+ // count for the fate of seh frame block.
+ for (auto *B : S->blocks()) {
+ auto &DummySymbol = G.addAnonymousSymbol(*B, 0, 0, false, false);
+ DenseSet<Block *> Children;
+ for (auto &E : B->edges()) {
+ auto &Sym = E.getTarget();
+ if (!Sym.isDefined())
+ continue;
+ Children.insert(&Sym.getBlock());
+ }
+ for (auto *Child : Children)
+ Child->addEdge(Edge(Edge::KeepAlive, 0, DummySymbol, 0));
+ }
+ return Error::success();
+ }
+
+private:
+ StringRef SEHFrameSectionName;
+};
+
+} // end namespace jitlink
+} // end namespace llvm
+
+#endif // LLVM_EXECUTIONENGINE_JITLINK_SEHFRAMESUPPORT_H
\ No newline at end of file
diff --git a/llvm/test/ExecutionEngine/JITLink/X86/COFF_pdata_no_strip.s b/llvm/test/ExecutionEngine/JITLink/X86/COFF_pdata_no_strip.s
new file mode 100644
index 000000000000..d6e0cba05194
--- /dev/null
+++ b/llvm/test/ExecutionEngine/JITLink/X86/COFF_pdata_no_strip.s
@@ -0,0 +1,31 @@
+# RUN: llvm-mc -filetype=obj -triple=x86_64-windows-msvc %s -o %t
+# RUN:
+# RUN: llvm-jitlink -abs __ImageBase=0xdeadbeaf -noexec %t \
+# RUN: -slab-allocate 100Kb -slab-address 0xfff00000 -slab-page-size 4096 \
+# RUN: -show-graph -noexec 2>&1 | FileCheck %s
+#
+# Check that basic seh frame inside pdata of alive function is not dead-stripped out.
+# CHECK: section .xdata:
+# CHECK-EMPTY:
+# CHECK-NEXT: block 0xfff00000 size = 0x00000008, align = 4, alignment-offset = 0
+# CHECK-NEXT: symbols:
+# CHECK-NEXT: 0xfff00000 (block + 0x00000000): size: 0x00000008, linkage: strong, scope: local, live - .xdata
+
+ .text
+
+ .def main;
+ .scl 2;
+ .type 32;
+ .endef
+ .globl main
+ .p2align 4, 0x90
+main:
+.seh_proc main
+ subq $40, %rsp
+ .seh_stackalloc 40
+ .seh_endprologue
+ movl $0, 36(%rsp)
+ nop
+ addq $40, %rsp
+ retq
+ .seh_endproc
diff --git a/llvm/test/ExecutionEngine/JITLink/X86/COFF_pdata_strip.s b/llvm/test/ExecutionEngine/JITLink/X86/COFF_pdata_strip.s
new file mode 100644
index 000000000000..2dad04fa18d0
--- /dev/null
+++ b/llvm/test/ExecutionEngine/JITLink/X86/COFF_pdata_strip.s
@@ -0,0 +1,43 @@
+# RUN: llvm-mc -filetype=obj -triple=x86_64-windows-msvc %s -o %t
+# RUN:
+# RUN: llvm-jitlink -abs __ImageBase=0xdeadbeaf -noexec %t \
+# RUN: -slab-allocate 100Kb -slab-address 0xfff00000 -slab-page-size 4096 \
+# RUN: -show-graph -noexec 2>&1 | FileCheck %s
+#
+# Check that basic seh frame of dead block is dead-stripped out
+#
+# CHECK: section .func:
+# CHECK-EMPTY:
+# CHECK-NEXT: section .xdata:
+# CHECK-EMPTY:
+# CHECK-NEXT: section .pdata:
+# CHECK-EMPTY:
+
+ .text
+
+ .def main;
+ .scl 2;
+ .type 32;
+ .endef
+ .globl main
+ .p2align 4, 0x90
+main:
+ retq
+
+ .section .func
+
+ .def func;
+ .scl 3;
+ .type 32;
+ .endef
+ .p2align 4, 0x90
+func:
+ .seh_proc func
+ subq $40, %rsp
+ .seh_stackalloc 40
+ .seh_endprologue
+ movl $0, 36(%rsp)
+ nop
+ addq $40, %rsp
+ retq
+ .seh_endproc
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