[LTO] Improve diagnostics handling when parsing module-level inline assembly (#75726)
Non-LTO compiles set the buffer name to "<inline asm>"
(`AsmPrinter::addInlineAsmDiagBuffer`) and pass diagnostics to
`ClangDiagnosticHandler` (through the `MCContext` handler in
`MachineModuleInfoWrapperPass::doInitialization`) to ensure that
the exit code is 1 in the presence of errors. In contrast, LTO compiles
spuriously succeed even if error messages are printed.
```
% cat a.c
void _start() {}
asm("unknown instruction");
% clang -c a.c
<inline asm>:1:1: error: invalid instruction mnemonic 'unknown'
1 | unknown instruction
| ^
1 error generated.
% clang -c -flto a.c; echo $? # -flto=thin is the same
error: invalid instruction mnemonic 'unknown'
unknown instruction
^~~~~~~
error: invalid instruction mnemonic 'unknown'
unknown instruction
^~~~~~~
0
```
`CollectAsmSymbols` parses inline assembly and is transitively called by
both `ModuleSummaryIndexAnalysis::run` and `WriteBitcodeToFile`, leading
to duplicate diagnostics.
This patch updates `CollectAsmSymbols` to be similar to non-LTO
compiles.
```
% clang -c -flto=thin a.c; echo $?
<inline asm>:1:1: error: invalid instruction mnemonic 'unknown'
1 | unknown instruction
| ^
1 errors generated.
1
```
The `HasErrors` check does not prevent duplicate warnings but assembler
warnings are very uncommon.
GitOrigin-RevId: 96aca7c51701f9b3c5dd8567fcddf29492008e6d
diff --git a/test/MachO/lto-module-asm-err.ll b/test/MachO/lto-module-asm-err.ll
index 45cd759..45dff24 100644
--- a/test/MachO/lto-module-asm-err.ll
+++ b/test/MachO/lto-module-asm-err.ll
@@ -3,13 +3,11 @@
; RUN: not %lld %t.bc -o /dev/null 2>&1 | FileCheck %s --check-prefix=REGULAR
;; For regular LTO, the original module name is lost.
-;; TODO Fix the line number
-; REGULAR: error: ld-temp.o <inline asm>:3:1: invalid instruction mnemonic 'invalid'
+; REGULAR: error: <inline asm>:2:1: invalid instruction mnemonic 'invalid'
-; RUN: opt -module-summary %s -o %t.bc
-; RUN: not %lld %t.bc -o /dev/null 2>&1 | FileCheck %s --check-prefix=THIN
+; RUN: not opt -module-summary %s -o /dev/null 2>&1 | FileCheck %s --check-prefix=THIN
-; THIN: error: {{.*}}.bc <inline asm>:2:1: invalid instruction mnemonic 'invalid'
+; THIN: error: <inline asm>:2:1: invalid instruction mnemonic 'invalid'
target triple = "x86_64-apple-macosx10.15.0"
target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
