release/19.x: [ARM] [Windows] Use IMAGE_SYM_CLASS_STATIC for private functions (#101828) #101904
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@cjacek What do you think about merging this PR to the release branch? |
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@llvm/pr-subscribers-backend-arm @llvm/pr-subscribers-mc Author: None (llvmbot) ChangesBackport 8dd065d Requested by: @mstorsjo Full diff: https://github.com/llvm/llvm-project/pull/101904.diff 3 Files Affected:
diff --git a/llvm/lib/Target/ARM/ARMAsmPrinter.cpp b/llvm/lib/Target/ARM/ARMAsmPrinter.cpp
index 642739a29d6b0..96d7074e6ef37 100644
--- a/llvm/lib/Target/ARM/ARMAsmPrinter.cpp
+++ b/llvm/lib/Target/ARM/ARMAsmPrinter.cpp
@@ -153,9 +153,9 @@ bool ARMAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
OptimizationGoals = 0;
if (Subtarget->isTargetCOFF()) {
- bool Internal = F.hasInternalLinkage();
- COFF::SymbolStorageClass Scl = Internal ? COFF::IMAGE_SYM_CLASS_STATIC
- : COFF::IMAGE_SYM_CLASS_EXTERNAL;
+ bool Local = F.hasLocalLinkage();
+ COFF::SymbolStorageClass Scl =
+ Local ? COFF::IMAGE_SYM_CLASS_STATIC : COFF::IMAGE_SYM_CLASS_EXTERNAL;
int Type = COFF::IMAGE_SYM_DTYPE_FUNCTION << COFF::SCT_COMPLEX_TYPE_SHIFT;
OutStreamer->beginCOFFSymbolDef(CurrentFnSym);
diff --git a/llvm/test/CodeGen/ARM/Windows/private-func.ll b/llvm/test/CodeGen/ARM/Windows/private-func.ll
new file mode 100644
index 0000000000000..2d030ae3fabbb
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/Windows/private-func.ll
@@ -0,0 +1,17 @@
+; RUN: llc -mtriple thumbv7-windows -filetype asm -o - %s | FileCheck %s
+
+define dso_local void @func1() {
+entry:
+ call void @func2()
+ ret void
+}
+
+define private void @func2() {
+entry:
+ ret void
+}
+
+; CHECK: .def .Lfunc2;
+; CHECK-NEXT: .scl 3;
+; CHECK-NEXT: .type 32;
+; CHECK-NEXT: .endef
diff --git a/llvm/test/MC/ARM/Windows/branch-reloc-offset.s b/llvm/test/MC/ARM/Windows/branch-reloc-offset.s
new file mode 100644
index 0000000000000..2e70a723ccf78
--- /dev/null
+++ b/llvm/test/MC/ARM/Windows/branch-reloc-offset.s
@@ -0,0 +1,57 @@
+// RUN: llvm-mc -triple thumbv7-windows-gnu -filetype obj %s -o - | llvm-objdump -D -r - | FileCheck %s
+
+ .text
+main:
+ nop
+ b .Ltarget
+ b .Lother_target
+
+// A private label target in the same section
+ .def .Ltarget
+ .scl 3
+ .type 32
+ .endef
+ .p2align 2
+.Ltarget:
+ bx lr
+
+// A private label target in another section
+ .section "other", "xr"
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ .def .Lother_target
+ .scl 3
+ .type 32
+ .endef
+ .p2align 2
+.Lother_target:
+ bx lr
+
+// Check that both branches have a relocation with a zero offset.
+//
+// CHECK: 00000000 <main>:
+// CHECK: 0: bf00 nop
+// CHECK: 2: f000 b800 b.w 0x6 <main+0x6> @ imm = #0x0
+// CHECK: 00000002: IMAGE_REL_ARM_BRANCH24T .Ltarget
+// CHECK: 6: f000 b800 b.w 0xa <main+0xa> @ imm = #0x0
+// CHECK: 00000006: IMAGE_REL_ARM_BRANCH24T .Lother_target
+// CHECK: a: bf00 nop
+// CHECK: 0000000c <.Ltarget>:
+// CHECK: c: 4770 bx lr
+// CHECK: 00000000 <other>:
+// CHECK: 0: bf00 nop
+// CHECK: 2: bf00 nop
+// CHECK: 4: bf00 nop
+// CHECK: 6: bf00 nop
+// CHECK: 8: bf00 nop
+// CHECK: a: bf00 nop
+// CHECK: c: bf00 nop
+// CHECK: e: bf00 nop
+// CHECK: 00000010 <.Lother_target>:
+// CHECK: 10: 4770 bx lr
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cjacek
approved these changes
Aug 4, 2024
…m#101828) For functions with private linkage, pick IMAGE_SYM_CLASS_STATIC rather than IMAGE_SYM_CLASS_EXTERNAL; GlobalValue::isInternalLinkage() only checks for InternalLinkage, while GlobalValue::isLocalLinkage() checks for both InternalLinkage and PrivateLinkage. This matches what the AArch64 target does, since commit 3406934. This activates a preexisting fix for the AArch64 target from 1e7f592, for the ARM target as well. When a relocation points at a symbol, one usually can convey an offset to the symbol by encoding it as an immediate in the instruction. However, for the ARM and AArch64 branch instructions, the immediate stored in the instruction is ignored by MS link.exe (and lld-link matches this aspect). (It would be simple to extend lld-link to support it - but such object files would be incompatible with MS link.exe.) This was worked around by 1e7f592 by emitting symbols into the object file symbol table, for temporary symbols that otherwise would have been omitted, if they have the class IMAGE_SYM_CLASS_STATIC, in order to avoid needing an offset in the relocated instruction. This change gives the symbols generated from functions with the IR level "private" linkage the right class, to activate that workaround. This fixes llvm#100101, fixing code generation for coroutines for Windows on ARM. After the change in f786881, coroutines generate a function with private linkage, and calls to this function were previously broken for this target. (cherry picked from commit 8dd065d)
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@mstorsjo (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR. |
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Backport 8dd065d
Requested by: @mstorsjo