[llvm] 3c478e1 - [SystemZ][z/OS] Relax check for additional symbols in PR section (#222435)

[via llvm-commits]

Author: Kai Nacke
Date: 2026-09-10T09:46:16-04:00
New Revision: 3c478e1597c11abbdafef9c08d7e11655ba1cdd5

URL: https://github.com/llvm/llvm-project/commit/3c478e1597c11abbdafef9c08d7e11655ba1cdd5
DIFF: https://github.com/llvm/llvm-project/commit/3c478e1597c11abbdafef9c08d7e11655ba1cdd5.diff

LOG: [SystemZ][z/OS] Relax check for additional symbols in PR section (#222435)

The current check in `emitLabel()` is too strict. Inside a PR, there
cannot be no other external visible label. However, temporary labels
which are used e.g. for calculating offsets can be emitted. A situation
in which this occurs is the emission of the DWARF EH tables, in which a
temporary symbol (with an empty name) is emitted at the begin of the
table, causing an error message. This change limits the error to
non-temporary labels.

Added: 
    llvm/test/CodeGen/SystemZ/zos-eh.ll

Modified: 
    llvm/lib/MC/MCGOFFStreamer.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/MC/MCGOFFStreamer.cpp b/llvm/lib/MC/MCGOFFStreamer.cpp
index 46cad50890b3c..bc5d58d61981e 100644
--- a/llvm/lib/MC/MCGOFFStreamer.cpp
+++ b/llvm/lib/MC/MCGOFFStreamer.cpp
@@ -60,7 +60,7 @@ void MCGOFFStreamer::emitLabel(MCSymbol *Symbol, SMLoc Loc) {
   if (Section->isPR()) {
     if (Section->getBeginSymbol() == nullptr)
       Section->setBeginSymbol(Symbol);
-    else
+    else if (!Symbol->isTemporary())
       getContext().reportError(
           Loc, "only one symbol can be defined in a PR section.");
   }

diff  --git a/llvm/test/CodeGen/SystemZ/zos-eh.ll b/llvm/test/CodeGen/SystemZ/zos-eh.ll
new file mode 100644
index 0000000000000..9439289bfbd6b
--- /dev/null
+++ b/llvm/test/CodeGen/SystemZ/zos-eh.ll
@@ -0,0 +1,42 @@
+; RUN: llc -mtriple s390x-zos -filetype=obj %s -o %t.o
+; RUN: llc -mtriple s390x-zos < %s | FileCheck %s
+
+define { ptr, i32 } @fn_with_lpad() personality ptr @__zos_cxx_personality_v2 {
+start:
+  %_0 = invoke double null(double 0.0, double 0.0, double 0.0)
+          to label %bb1 unwind label %terminate
+terminate:
+  %0 = landingpad { ptr, i32 }
+          filter [0 x ptr] zeroinitializer
+  ret { ptr, i32 } %0
+bb1:
+  ret { ptr, i32 } zeroinitializer
+}
+
+declare i32 @__zos_cxx_personality_v2(...)
+
+; CHECK:      C_WSA64 CATTR ALIGN(2),FILL(0),NOTEXECUTABLE,RMODE(64),PART(.gcc_excepti
+; CHECK-NEXT:                ion_table.fn_with_lpad)
+; CHECK-NEXT: .gcc_exception_table.fn_with_lpad XATTR LINKAGE(XPLINK),REFERENCE(DATA),
+; CHECK-NEXT:                ,SCOPE(SECTION)
+; CHECK-NEXT:  DS 0B
+; CHECK-NEXT: * @LPStart Encoding = omit
+; CHECK-NEXT:  DC XL1'FF'
+; CHECK-NEXT: * @TType Encoding = absptr
+; CHECK-NEXT:  DC XL1'00'
+; CHECK-NEXT: * Call site Encoding = uleb128
+; CHECK-NEXT:  DC XL1'01'
+; CHECK-NEXT: * >> Call Site 1 <<
+; CHECK-NEXT: *   Call between L#tmp0 and L#tmp1
+; CHECK-NEXT: *     jumps to L#tmp2
+; CHECK-NEXT: *   On action: 1
+; CHECK-NEXT:  DC XL1'01'
+; CHECK-NEXT: * >> Action Record 1 <<
+; CHECK-NEXT: *   Filter TypeInfo -1
+; CHECK-NEXT:  DC XL1'7F'
+; CHECK-NEXT: *   No further actions
+; CHECK-NEXT:  DC XL1'00'
+; CHECK-NEXT:  DS 0B
+; CHECK-NEXT: * >> Filter TypeInfos <<
+; CHECK-NEXT:  DC XL1'00'
+; CHECK-NEXT:  DS 0B