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[IR] Require that global value initializers are sized #137358

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[IR] Require that global value initializers are sized #137358

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2 changes: 1 addition & 1 deletion llvm/docs/LangRef.rst
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Expand Up @@ -700,7 +700,7 @@ Global Variables
Global variables define regions of memory allocated at compilation time
instead of run-time.

Global variable definitions must be initialized.
Global variable definitions must be initialized with a sized value.

Global variables in other translation units can also be declared, in which
case they don't have an initializer.
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2 changes: 2 additions & 0 deletions llvm/lib/IR/Verifier.cpp
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Expand Up @@ -835,6 +835,8 @@ void Verifier::visitGlobalVariable(const GlobalVariable &GV) {
"Global variable initializer type does not match global "
"variable type!",
&GV);
Check(GV.getInitializer()->getType()->isSized(),
"Global variable initializer must be sized", &GV);
// If the global has common linkage, it must have a zero initializer and
// cannot be constant.
if (GV.hasCommonLinkage()) {
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6 changes: 5 additions & 1 deletion llvm/test/Assembler/2005-05-05-OpaqueUndefValues.ll
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Expand Up @@ -2,4 +2,8 @@
; RUN: verify-uselistorder %s

%t = type opaque
@x = global %t undef

define void @test() {
%sel = select i1 true, %t undef, %t poison
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We should also forbid "select"/"undef"/"poison"/"zeroinitialzer", I think? I don't see any reason to allow writing values with opaque types in any context; it's about as meaningful as a global variable with an opaque type.

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Done in #137625.

ret void
}
2 changes: 1 addition & 1 deletion llvm/test/Transforms/InstSimplify/gv-alloca-cmp.ll
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Expand Up @@ -46,7 +46,7 @@ define i1 @cmp_gv_weak_alloca() {
}

%opaque = type opaque
@gv_unsized = weak global %opaque zeroinitializer, align 16
@gv_unsized = external global %opaque, align 16

define i1 @cmp_gv_unsized_alloca() {
; CHECK-LABEL: define i1 @cmp_gv_unsized_alloca() {
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6 changes: 6 additions & 0 deletions llvm/test/Verifier/global-initializer-sized.ll
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@@ -0,0 +1,6 @@
; RUN: not llvm-as < %s 2>&1 | FileCheck %s

%t = type opaque
@g = global %t undef

; CHECK: Global variable initializer must be sized
6 changes: 3 additions & 3 deletions llvm/test/Verifier/scalable-global-vars.ll
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Expand Up @@ -13,7 +13,7 @@

; CHECK-NEXT: Globals cannot contain scalable types
; CHECK-NEXT: ptr @ScalableVecStructGlobal
@ScalableVecStructGlobal = global { i32, <vscale x 4 x i32> } zeroinitializer
@ScalableVecStructGlobal = external global { i32, <vscale x 4 x i32> }

; CHECK-NEXT: Globals cannot contain scalable types
; CHECK-NEXT: ptr @StructTestGlobal
Expand All @@ -23,9 +23,9 @@
; CHECK-NEXT: Globals cannot contain scalable types
; CHECK-NEXT: ptr @StructArrayTestGlobal
%struct.array.test = type { [2 x <vscale x 1 x double>] }
@StructArrayTestGlobal = global %struct.array.test zeroinitializer
@StructArrayTestGlobal = external global %struct.array.test

; CHECK-NEXT: Globals cannot contain scalable types
; CHECK-NEXT: ptr @StructTargetTestGlobal
%struct.target.test = type { target("aarch64.svcount"), target("aarch64.svcount") }
@StructTargetTestGlobal = global %struct.target.test zeroinitializer
@StructTargetTestGlobal = external global %struct.target.test
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