Perform Clang IRGen during check (#6569)

Background:
https://docs.google.com/document/d/1wi85FRiWh4X9A-gCYMVGKR40-q5fM6-3JaSpePk-XCY/edit?usp=sharing
And specifically this work is essentially an alternative to #5543

Clang's code generation is implemented through an ASTListener
(clang::CodeGenerator) that is attached throughout Clang's
parsing/sema/code
generation phases and acts on Clang AST incrementally throughout that
process.

Prior to this patch, Carbon has only created the CodeGenerator during
Carbon's
`lower` phase, missing out on key callbacks that would be made by Clang
during
`check`. Some of these issues were addressed by #6237 and #6483 - but
there were
still remaining cases where the delayed processing lead to missing
functionality.

With #6483 much of the Clang code that made multithreaded complexity of
#5543 is
no longer present, and we have access to the point of ASTListener
registration
so we can register the CodeGenerator there and consume its resulting
llvm::Module during lower.

Examples of some of the bugs this addresses are seen in the linked doc,
and
checked in as tests in this change in
`clang_code_generator_callbacks.carbon`

An indicental bug that's also fixed, and caused all the other test case
churn,
is that the `CodeGenerator` created during `lower` wasn't getting passed
the
Clang `CodeGenOpts` and was creating its own default - so, most notably,
optimization flags were not respected. This meant that the LLVM IR from
Clang
was always -O0 style IR (optnone, no inlinehint, no TBAA, etc). With
this
change, now the Clang IRGen gets the real `CodeGenOpts` and respects
optimization/other flags specified there.

This is only meant to be a rough proof of concept - I'm totally open to
reworking this in any way (even quite substantially) if folks have ideas
about
how this should be implemented most generally/elegantly/etc.
This commit is contained in:
David Blaikie
2026-01-14 00:54:37 +00:00
committed by GitHub
parent c64117d0e0
commit f1f6005d4a
36 changed files with 3059 additions and 2363 deletions
@@ -38,35 +38,41 @@ fn F() {
// CHECK:STDOUT: $_ZN1XIiE1fEi = comdat any
// CHECK:STDOUT:
// CHECK:STDOUT: ; Function Attrs: nounwind
// CHECK:STDOUT: define void @_CF.Main() #0 !dbg !7 {
// CHECK:STDOUT: define void @_CF.Main() #0 !dbg !12 {
// CHECK:STDOUT: entry:
// CHECK:STDOUT: call void @_ZN1XIiE1fEi(i32 42), !dbg !10
// CHECK:STDOUT: ret void, !dbg !11
// CHECK:STDOUT: call void @_ZN1XIiE1fEi(i32 42), !dbg !15
// CHECK:STDOUT: ret void, !dbg !16
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: ; Function Attrs: mustprogress noinline nounwind optnone
// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN1XIiE1fEi(i32 %t) #1 comdat align 2 {
// CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN1XIiE1fEi(i32 noundef %t) #1 comdat align 2 {
// CHECK:STDOUT: entry:
// CHECK:STDOUT: %t.addr = alloca i32, align 4
// CHECK:STDOUT: store i32 %t, ptr %t.addr, align 4
// CHECK:STDOUT: store i32 %t, ptr %t.addr, align 4, !tbaa !8
// CHECK:STDOUT: ret void
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: attributes #0 = { nounwind }
// CHECK:STDOUT: attributes #1 = { mustprogress noinline nounwind optnone "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="0" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
// CHECK:STDOUT: attributes #1 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
// CHECK:STDOUT:
// CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4}
// CHECK:STDOUT: !llvm.dbg.cu = !{!5}
// CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
// CHECK:STDOUT: !llvm.dbg.cu = !{!6}
// CHECK:STDOUT: !llvm.errno.tbaa = !{!8}
// CHECK:STDOUT:
// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
// CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
// CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
// CHECK:STDOUT: !5 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !6, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
// CHECK:STDOUT: !6 = !DIFile(filename: "use_class_template.carbon", directory: "")
// CHECK:STDOUT: !7 = distinct !DISubprogram(name: "F", linkageName: "_CF.Main", scope: null, file: !6, line: 6, type: !8, spFlags: DISPFlagDefinition, unit: !5)
// CHECK:STDOUT: !8 = !DISubroutineType(types: !9)
// CHECK:STDOUT: !9 = !{null}
// CHECK:STDOUT: !10 = !DILocation(line: 8, column: 3, scope: !7)
// CHECK:STDOUT: !11 = !DILocation(line: 6, column: 1, scope: !7)
// CHECK:STDOUT: !5 = !{i32 7, !"uwtable", i32 2}
// CHECK:STDOUT: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !7, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
// CHECK:STDOUT: !7 = !DIFile(filename: "use_class_template.carbon", directory: "")
// CHECK:STDOUT: !8 = !{!9, !9, i64 0}
// CHECK:STDOUT: !9 = !{!"int", !10, i64 0}
// CHECK:STDOUT: !10 = !{!"omnipotent char", !11, i64 0}
// CHECK:STDOUT: !11 = !{!"Simple C++ TBAA"}
// CHECK:STDOUT: !12 = distinct !DISubprogram(name: "F", linkageName: "_CF.Main", scope: null, file: !7, line: 6, type: !13, spFlags: DISPFlagDefinition, unit: !6)
// CHECK:STDOUT: !13 = !DISubroutineType(types: !14)
// CHECK:STDOUT: !14 = !{null}
// CHECK:STDOUT: !15 = !DILocation(line: 8, column: 3, scope: !12)
// CHECK:STDOUT: !16 = !DILocation(line: 6, column: 1, scope: !12)