Files
carbon-lang/toolchain/lower/testdata/array/base.carbon
T
Dana Jansens e682a6660d Avoid adding extraneous local instructions while importing witness table entries (#6180)
When deducing arguments for generic parameters of an `impl`, the
deduction calls `Convert` on the input arguments. Often, the input
argument is a facet, and needs to be converted to a type via
FacetAccessType in order to produce a different facet. These
instructions end up being added to the semir, but only their constant
values are needed for the resulting specific returned from Deduce.

In the best case, these extra instructions are just noise in the semir,
or they just cause instruction names to get differentiated with larger
suffixes.

In the worst case, these extra instructions contain references to
instructions from a generic context, and leak them out of that generic
context and into another. In particular, when importing a
LookupImplWitness instruction, the re-evaluation of it can do deduce
(when the lookup is against a generic `impl`). The instructions created
in Deduce are not part of the import, and end up referring to imported
instructions from the local context, which leads to confusion in the
toolchain, and can crash.

The `import_self_specific.carbon` test demonstrates this. It causes the
`I.F` function to be imported from the `I` interface when building the
witness table for the `impl`. Doing so imports the specific of `C` which
includes a LookupImplWitness for `Self.Accoc` in `I`. The `Self` is a
BindSymbolicName with generic binding index 0, in `I`. When Convert
creates instructions in the generic `impl forall D`, however, they end
up referencing and including this BindSymbolicName into its eval block.
But the generic binding 0 in the `impl` is a very different thing (a
value of type `E`). This confusion leads to crashes.
2025-10-09 16:07:30 +00:00

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// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
// INCLUDE-FILE: toolchain/testing/testdata/min_prelude/primitives.carbon
//
// AUTOUPDATE
// TIP: To test this file alone, run:
// TIP: bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/lower/testdata/array/base.carbon
// TIP: To dump output, run:
// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/lower/testdata/array/base.carbon
fn Run() {
var a: array(i32, 1) = (1,);
var b: array(f64, 2) = (11.1, 2.2,);
var c: array((), 5) = ((), (), (), (), (),);
var d: (i32, i32, i32) = (1, 2, 3);
var e: array(i32, 3) = d;
}
// CHECK:STDOUT: ; ModuleID = 'base.carbon'
// CHECK:STDOUT: source_filename = "base.carbon"
// CHECK:STDOUT:
// CHECK:STDOUT: @array.237.loc14_3 = internal constant [1 x i32] [i32 1]
// CHECK:STDOUT: @array.b91.loc15_3 = internal constant [2 x double] [double 1.110000e+01, double 2.200000e+00]
// CHECK:STDOUT: @array.1cb.loc16_3 = internal constant [5 x {}] zeroinitializer
// CHECK:STDOUT: @tuple.loc17_3 = internal constant { i32, i32, i32 } { i32 1, i32 2, i32 3 }
// CHECK:STDOUT:
// CHECK:STDOUT: define void @main() !dbg !4 {
// CHECK:STDOUT: entry:
// CHECK:STDOUT: %a.var = alloca [1 x i32], align 4, !dbg !7
// CHECK:STDOUT: %b.var = alloca [2 x double], align 8, !dbg !8
// CHECK:STDOUT: %c.var = alloca [5 x {}], align 8, !dbg !9
// CHECK:STDOUT: %d.var = alloca { i32, i32, i32 }, align 8, !dbg !10
// CHECK:STDOUT: %e.var = alloca [3 x i32], align 4, !dbg !11
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %a.var), !dbg !7
// CHECK:STDOUT: %.loc14_29.3.array.index = getelementptr inbounds [1 x i32], ptr %a.var, i32 0, i64 0, !dbg !12
// CHECK:STDOUT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 %a.var, ptr align 4 @array.237.loc14_3, i64 4, i1 false), !dbg !7
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %b.var), !dbg !8
// CHECK:STDOUT: %.loc15_37.3.array.index = getelementptr inbounds [2 x double], ptr %b.var, i32 0, i64 0, !dbg !13
// CHECK:STDOUT: %.loc15_37.6.array.index = getelementptr inbounds [2 x double], ptr %b.var, i32 0, i64 1, !dbg !13
// CHECK:STDOUT: call void @llvm.memcpy.p0.p0.i64(ptr align 8 %b.var, ptr align 8 @array.b91.loc15_3, i64 16, i1 false), !dbg !8
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %c.var), !dbg !9
// CHECK:STDOUT: %.loc16_45.2.array.index = getelementptr inbounds [5 x {}], ptr %c.var, i32 0, i64 0, !dbg !14
// CHECK:STDOUT: %.loc16_45.4.array.index = getelementptr inbounds [5 x {}], ptr %c.var, i32 0, i64 1, !dbg !14
// CHECK:STDOUT: %.loc16_45.6.array.index = getelementptr inbounds [5 x {}], ptr %c.var, i32 0, i64 2, !dbg !14
// CHECK:STDOUT: %.loc16_45.8.array.index = getelementptr inbounds [5 x {}], ptr %c.var, i32 0, i64 3, !dbg !14
// CHECK:STDOUT: %.loc16_45.10.array.index = getelementptr inbounds [5 x {}], ptr %c.var, i32 0, i64 4, !dbg !14
// CHECK:STDOUT: call void @llvm.memcpy.p0.p0.i64(ptr align 1 %c.var, ptr align 1 @array.1cb.loc16_3, i64 0, i1 false), !dbg !9
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %d.var), !dbg !10
// CHECK:STDOUT: %tuple.elem0.loc17.tuple.elem = getelementptr inbounds nuw { i32, i32, i32 }, ptr %d.var, i32 0, i32 0, !dbg !15
// CHECK:STDOUT: %tuple.elem1.loc17.tuple.elem = getelementptr inbounds nuw { i32, i32, i32 }, ptr %d.var, i32 0, i32 1, !dbg !15
// CHECK:STDOUT: %tuple.elem2.loc17.tuple.elem = getelementptr inbounds nuw { i32, i32, i32 }, ptr %d.var, i32 0, i32 2, !dbg !15
// CHECK:STDOUT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 %d.var, ptr align 4 @tuple.loc17_3, i64 12, i1 false), !dbg !10
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %e.var), !dbg !11
// CHECK:STDOUT: %tuple.elem0.loc18.tuple.elem = getelementptr inbounds nuw { i32, i32, i32 }, ptr %d.var, i32 0, i32 0, !dbg !16
// CHECK:STDOUT: %.loc18_26.1 = load i32, ptr %tuple.elem0.loc18.tuple.elem, align 4, !dbg !16
// CHECK:STDOUT: %.loc18_26.2.array.index = getelementptr inbounds [3 x i32], ptr %e.var, i32 0, i64 0, !dbg !16
// CHECK:STDOUT: store i32 %.loc18_26.1, ptr %.loc18_26.2.array.index, align 4, !dbg !16
// CHECK:STDOUT: %tuple.elem1.loc18.tuple.elem = getelementptr inbounds nuw { i32, i32, i32 }, ptr %d.var, i32 0, i32 1, !dbg !16
// CHECK:STDOUT: %.loc18_26.4 = load i32, ptr %tuple.elem1.loc18.tuple.elem, align 4, !dbg !16
// CHECK:STDOUT: %.loc18_26.5.array.index = getelementptr inbounds [3 x i32], ptr %e.var, i32 0, i64 1, !dbg !16
// CHECK:STDOUT: store i32 %.loc18_26.4, ptr %.loc18_26.5.array.index, align 4, !dbg !16
// CHECK:STDOUT: %tuple.elem2.loc18.tuple.elem = getelementptr inbounds nuw { i32, i32, i32 }, ptr %d.var, i32 0, i32 2, !dbg !16
// CHECK:STDOUT: %.loc18_26.7 = load i32, ptr %tuple.elem2.loc18.tuple.elem, align 4, !dbg !16
// CHECK:STDOUT: %.loc18_26.8.array.index = getelementptr inbounds [3 x i32], ptr %e.var, i32 0, i64 2, !dbg !16
// CHECK:STDOUT: store i32 %.loc18_26.7, ptr %.loc18_26.8.array.index, align 4, !dbg !16
// CHECK:STDOUT: ret void, !dbg !17
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #0
// CHECK:STDOUT:
// CHECK:STDOUT: ; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #1
// CHECK:STDOUT:
// CHECK:STDOUT: ; uselistorder directives
// CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 4, 3, 2, 1, 0 }
// CHECK:STDOUT: uselistorder ptr @llvm.memcpy.p0.p0.i64, { 3, 2, 1, 0 }
// CHECK:STDOUT:
// CHECK:STDOUT: attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
// CHECK:STDOUT: attributes #1 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
// CHECK:STDOUT:
// CHECK:STDOUT: !llvm.module.flags = !{!0, !1}
// CHECK:STDOUT: !llvm.dbg.cu = !{!2}
// CHECK:STDOUT:
// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
// CHECK:STDOUT: !3 = !DIFile(filename: "base.carbon", directory: "")
// CHECK:STDOUT: !4 = distinct !DISubprogram(name: "Run", linkageName: "main", scope: null, file: !3, line: 13, type: !5, spFlags: DISPFlagDefinition, unit: !2)
// CHECK:STDOUT: !5 = !DISubroutineType(types: !6)
// CHECK:STDOUT: !6 = !{}
// CHECK:STDOUT: !7 = !DILocation(line: 14, column: 3, scope: !4)
// CHECK:STDOUT: !8 = !DILocation(line: 15, column: 3, scope: !4)
// CHECK:STDOUT: !9 = !DILocation(line: 16, column: 3, scope: !4)
// CHECK:STDOUT: !10 = !DILocation(line: 17, column: 3, scope: !4)
// CHECK:STDOUT: !11 = !DILocation(line: 18, column: 3, scope: !4)
// CHECK:STDOUT: !12 = !DILocation(line: 14, column: 26, scope: !4)
// CHECK:STDOUT: !13 = !DILocation(line: 15, column: 26, scope: !4)
// CHECK:STDOUT: !14 = !DILocation(line: 16, column: 25, scope: !4)
// CHECK:STDOUT: !15 = !DILocation(line: 17, column: 28, scope: !4)
// CHECK:STDOUT: !16 = !DILocation(line: 18, column: 26, scope: !4)
// CHECK:STDOUT: !17 = !DILocation(line: 13, column: 1, scope: !4)