[lld] [LLD][COFF] Split native and EC .CRT chunks on ARM64X (PR #127203)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lld

Author: Jacek Caban (cjacek)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/127203.diff


3 Files Affected:

- (modified) lld/COFF/Writer.cpp (+11) 
- (modified) lld/COFF/Writer.h (+3) 
- (added) lld/test/COFF/arm64x-crt-sec.s (+42) 


``````````diff
diff --git a/lld/COFF/Writer.cpp b/lld/COFF/Writer.cpp
index 678de915b6cdb..504558087c80d 100644
--- a/lld/COFF/Writer.cpp
+++ b/lld/COFF/Writer.cpp
@@ -403,6 +403,12 @@ void OutputSection::addContributingPartialSection(PartialSection *sec) {
   contribSections.push_back(sec);
 }
 
+void OutputSection::splitECChunks() {
+  llvm::stable_sort(chunks, [=](const Chunk *a, const Chunk *b) {
+    return (a->getMachine() != ARM64) < (b->getMachine() != ARM64);
+  });
+}
+
 // Check whether the target address S is in range from a relocation
 // of type relType at address P.
 bool Writer::isInRange(uint16_t relType, uint64_t s, uint64_t p, int margin,
@@ -1156,6 +1162,11 @@ void Writer::createSections() {
     sec->addContributingPartialSection(pSec);
   }
 
+  if (ctx.hybridSymtab) {
+    if (OutputSection *sec = findSection(".CRT"))
+      sec->splitECChunks();
+  }
+
   // Finally, move some output sections to the end.
   auto sectionOrder = [&](const OutputSection *s) {
     // Move DISCARDABLE (or non-memory-mapped) sections to the end of file
diff --git a/lld/COFF/Writer.h b/lld/COFF/Writer.h
index 9004bb310d073..7e458b766bae8 100644
--- a/lld/COFF/Writer.h
+++ b/lld/COFF/Writer.h
@@ -50,6 +50,9 @@ class OutputSection {
   void writeHeaderTo(uint8_t *buf, bool isDebug);
   void addContributingPartialSection(PartialSection *sec);
 
+  // Sort chunks to split native and EC sections on hybrid targets.
+  void splitECChunks();
+
   // Returns the size of this section in an executable memory image.
   // This may be smaller than the raw size (the raw size is multiple
   // of disk sector size, so there may be padding at end), or may be
diff --git a/lld/test/COFF/arm64x-crt-sec.s b/lld/test/COFF/arm64x-crt-sec.s
new file mode 100644
index 0000000000000..5be70a1845f12
--- /dev/null
+++ b/lld/test/COFF/arm64x-crt-sec.s
@@ -0,0 +1,42 @@
+// REQUIRES: aarch64, x86
+// RUN: split-file %s %t.dir && cd %t.dir
+
+// RUN: llvm-mc -filetype=obj -triple=aarch64-windows crt1-arm64.s -o crt1-arm64.obj
+// RUN: llvm-mc -filetype=obj -triple=aarch64-windows crt2-arm64.s -o crt2-arm64.obj
+// RUN: llvm-mc -filetype=obj -triple=arm64ec-windows crt1-arm64ec.s -o crt1-arm64ec.obj
+// RUN: llvm-mc -filetype=obj -triple=x86_64-windows crt2-amd64.s -o crt2-amd64.obj
+
+// Check that .CRT chunks are correctly sorted and that EC and native chunks are split.
+
+// RUN: lld-link -out:out.dll -machine:arm64x -dll -noentry crt1-arm64.obj crt2-arm64.obj crt1-arm64ec.obj crt2-amd64.obj
+// RUN: llvm-readobj --hex-dump=.CRT out.dll | FileCheck %s
+
+// RUN: lld-link -out:out2.dll -machine:arm64x -dll -noentry crt1-arm64.obj crt1-arm64ec.obj crt2-arm64.obj crt2-amd64.obj
+// RUN: llvm-readobj --hex-dump=.CRT out2.dll | FileCheck %s
+
+// RUN: lld-link -out:out3.dll -machine:arm64x -dll -noentry crt2-amd64.obj crt1-arm64ec.obj crt2-arm64.obj crt1-arm64.obj
+// RUN: llvm-readobj --hex-dump=.CRT out3.dll | FileCheck %s
+
+// CHECK:      0x180002000 01000000 00000000 02000000 00000000
+// CHECK-NEXT: 0x180002010 03000000 00000000 11000000 00000000
+// CHECK-NEXT: 0x180002020 12000000 00000000 13000000 00000000
+
+#--- crt1-arm64.s
+        .section .CRT$A,"dr"
+        .xword 1
+        .section .CRT$Z,"dr"
+        .xword 3
+
+#--- crt2-arm64.s
+        .section .CRT$B,"dr"
+        .xword 2
+
+#--- crt1-arm64ec.s
+        .section .CRT$A,"dr"
+        .xword 0x11
+        .section .CRT$Z,"dr"
+        .xword 0x13
+
+#--- crt2-amd64.s
+        .section .CRT$B,"dr"
+        .quad 0x12

``````````

</details>


https://github.com/llvm/llvm-project/pull/127203