[SelectionDAG][Statepoint] Fix truncation of gc.statepoint ID argument

[Il-Capitano]

The ID argument of gc.statepoint gets incorrectly truncated to 32 bits during code generation.
This is fixed by using uint64_t instead of unsigned for the ID member in SelectionDAGBuilder::StatepointLoweringInfo, and a patchpoint test case is extended to check for 64 bit ID generation in stackmaps.

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[llvmbot]

@llvm/pr-subscribers-backend-aarch64

@llvm/pr-subscribers-llvm-selectiondag

Author: None (Il-Capitano)

Changes

The ID argument of gc.statepoint gets incorrectly truncated to 32 bits during code generation.
This is fixed by using uint64_t instead of unsigned for the ID member in SelectionDAGBuilder::StatepointLoweringInfo, and a patchpoint test case is extended to check for 64 bit ID generation in stackmaps.

---

Full diff: https://github.com/llvm/llvm-project/pull/85908.diff

2 Files Affected:

• (modified) llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h (+1-1)
• (modified) llvm/test/CodeGen/AArch64/stackmap.ll (+16-2)

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
index dcf46e0563ff9d..211e1653de560a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -449,7 +449,7 @@ class SelectionDAGBuilder {
     ArrayRef<const Use> GCTransitionArgs;
 
     /// The ID that the resulting STATEPOINT instruction has to report.
-    unsigned ID = -1;
+    uint64_t ID = -1;
 
     /// Information regarding the underlying call instruction.
     TargetLowering::CallLoweringInfo CLI;
diff --git a/llvm/test/CodeGen/AArch64/stackmap.ll b/llvm/test/CodeGen/AArch64/stackmap.ll
index ce7dcc4a59e9a7..dfef9ccbe304f0 100644
--- a/llvm/test/CodeGen/AArch64/stackmap.ll
+++ b/llvm/test/CodeGen/AArch64/stackmap.ll
@@ -13,7 +13,7 @@
 ; Num LargeConstants
 ; CHECK-NEXT:   .word 4
 ; Num Callsites
-; CHECK-NEXT:   .word 18
+; CHECK-NEXT:   .word 22
 
 ; Functions and stack size
 ; CHECK-NEXT:   .xword constantargs
@@ -434,14 +434,27 @@ entry:
 ; CHECK-LABEL:  .word .L{{.*}}-longid
 ; CHECK:        .xword -1
 ; CHECK-LABEL:  .word .L{{.*}}-longid
-define void @longid() {
+; CHECK:        .xword 4294967295
+; CHECK-LABEL:  .word .L{{.*}}-longid
+; CHECK:        .xword 4294967296
+; CHECK-LABEL:  .word .L{{.*}}-longid
+; CHECK:        .xword 9223372036854775807
+; CHECK-LABEL:  .word .L{{.*}}-longid
+; CHECK:        .xword -1
+; CHECK-LABEL:  .word .L{{.*}}-longid
+define void @longid() gc "statepoint-example" {
 entry:
   tail call void (i64, i32, ptr, i32, ...) @llvm.experimental.patchpoint.void(i64 4294967295, i32 0, ptr null, i32 0)
   tail call void (i64, i32, ptr, i32, ...) @llvm.experimental.patchpoint.void(i64 4294967296, i32 0, ptr null, i32 0)
   tail call void (i64, i32, ptr, i32, ...) @llvm.experimental.patchpoint.void(i64 9223372036854775807, i32 0, ptr null, i32 0)
   tail call void (i64, i32, ptr, i32, ...) @llvm.experimental.patchpoint.void(i64 -1, i32 0, ptr null, i32 0)
+  %safepoint_token1 = tail call token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 4294967295, i32 0, ptr elementtype(void ()) @return_void, i32 0, i32 0, i32 0, i32 0)
+  %safepoint_token2 = tail call token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 4294967296, i32 0, ptr elementtype(void ()) @return_void, i32 0, i32 0, i32 0, i32 0)
+  %safepoint_token3 = tail call token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 9223372036854775807, i32 0, ptr elementtype(void ()) @return_void, i32 0, i32 0, i32 0, i32 0)
+  %safepoint_token4 = tail call token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 -1, i32 0, ptr elementtype(void ()) @return_void, i32 0, i32 0, i32 0, i32 0)
   ret void
 }
+declare void @return_void()
 
 ; Map a value when R11 is the only free register.
 ; The scratch register should not be used for a live stackmap value.
@@ -537,3 +550,4 @@ define void @floats(float %f, double %g) {
 declare void @llvm.experimental.stackmap(i64, i32, ...)
 declare void @llvm.experimental.patchpoint.void(i64, i32, ptr, i32, ...)
 declare i64 @llvm.experimental.patchpoint.i64(i64, i32, ptr, i32, ...)
+declare token @llvm.experimental.gc.statepoint.p0(i64, i32, ptr, i32, i32, ...)

[Il-Capitano]

@arsenm Pinging to ask if you could merge this?

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