[llvm] a8e582c - [ThinLTO] Always parse module level inline asm with At&t dialect (PR46503)

[Hans Wennborg via llvm-commits]

Author: Hans Wennborg
Date: 2020-07-01T09:43:45+02:00
New Revision: a8e582c8307ba1d33c05d272b5c1b755fa809b51

URL: https://github.com/llvm/llvm-project/commit/a8e582c8307ba1d33c05d272b5c1b755fa809b51
DIFF: https://github.com/llvm/llvm-project/commit/a8e582c8307ba1d33c05d272b5c1b755fa809b51.diff

LOG: [ThinLTO] Always parse module level inline asm with At&t dialect (PR46503)

clang-cl passes -x86-asm-syntax=intel to the cc1 invocation so that
assembly listings produced by the /FA flag are printed in Intel dialect.
That flag however should not affect the *parsing* of inline assembly in
the program. (See r322652)

When compiling normally, AsmPrinter::emitInlineAsm is used for
assembling and defaults to At&t dialect. However, when compiling for
ThinLTO, the code which parses module level inline asm to find symbols
for the symbol table was failing to set the dialect. This patch fixes
that. (See the bug for more details.)

Differential revision: https://reviews.llvm.org/D82862

Added: 
    clang/test/CodeGen/thinlto-inline-asm.c

Modified: 
    llvm/lib/Object/ModuleSymbolTable.cpp

Removed: 
    


################################################################################
diff  --git a/clang/test/CodeGen/thinlto-inline-asm.c b/clang/test/CodeGen/thinlto-inline-asm.c
new file mode 100644
index 000000000000..a41cba6fadc1
--- /dev/null
+++ b/clang/test/CodeGen/thinlto-inline-asm.c
@@ -0,0 +1,21 @@
+// REQUIRES: x86-registered-target
+
+// RUN: %clang_cc1 -triple x86_64-pc-windows-msvc19.11.0 -emit-llvm-bc \
+// RUN:   -flto=thin -mllvm -x86-asm-syntax=intel -v \
+// RUN:   -o %t.obj %s 2>&1 | FileCheck --check-prefix=CLANG %s
+//
+// RUN: llvm-lto2 dump-symtab %t.obj | FileCheck --check-prefix=SYMTAB %s
+
+// Module-level inline asm is parsed with At&t syntax. Test that the
+// -x86-asm-syntax flag does not affect this.
+
+// CLANG-NOT: unknown token in expression
+// SYMTAB: D------X foo
+// SYMTAB: D------X bar
+
+void foo() {}
+
+asm(".globl bar      \n"
+    "bar:            \n"
+    "  xor %eax, %eax\n"
+    "  ret           \n");

diff  --git a/llvm/lib/Object/ModuleSymbolTable.cpp b/llvm/lib/Object/ModuleSymbolTable.cpp
index 45bcf7481890..7f3055b5dcfa 100644
--- a/llvm/lib/Object/ModuleSymbolTable.cpp
+++ b/llvm/lib/Object/ModuleSymbolTable.cpp
@@ -23,6 +23,7 @@
 #include "llvm/IR/GlobalAlias.h"
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/Module.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCContext.h"
@@ -116,6 +117,10 @@ initializeRecordStreamer(const Module &M,
   if (!TAP)
     return;
 
+  // Module-level inline asm is assumed to use At&t syntax (see
+  // AsmPrinter::doInitialization()).
+  Parser->setAssemblerDialect(InlineAsm::AD_ATT);
+
   Parser->setTargetParser(*TAP);
   if (Parser->Run(false))
     return;