[PATCH] D15399: MS inline ASM: mark the function noinline if the asm has labels (PR23715)

[Hans Wennborg via cfe-commits]

hans created this revision.
hans added a reviewer: rnk.
hans added a subscriber: cfe-commits.

This avoids defining the same label twice if the function gets inlined.

It's pretty hacky, but also very non-intrusive. (I also played with adding a flag on the MSAsmStmt and set that in ParseMicrosoftAsmStatement, but all that churn doesn't really buy us much.)

http://reviews.llvm.org/D15399

Files:
  lib/CodeGen/CGStmt.cpp
  test/CodeGen/ms-inline-asm.c

Index: test/CodeGen/ms-inline-asm.c
===================================================================
--- test/CodeGen/ms-inline-asm.c
+++ test/CodeGen/ms-inline-asm.c
@@ -533,7 +533,7 @@
     label:
     jmp label
   }
-  // CHECK-LABEL: define void @label1
+  // CHECK: define void @label1() [[ATTR1:#[0-9]+]] {
   // CHECK: call void asm sideeffect inteldialect "{{.*}}__MSASMLABEL_.1__label:\0A\09jmp {{.*}}__MSASMLABEL_.1__label", "~{dirflag},~{fpsr},~{flags}"()
 }
 
@@ -581,3 +581,6 @@
 }
 // CHECK-LABEL: define i32 @test_indirect_field(
 // CHECK: call i32 asm sideeffect inteldialect "mov eax, dword ptr $1",
+
+// Functions with inline asm containing labels should be noinline (PR23715)
+// CHECK: attributes [[ATTR1]] = { {{.*}}noinline{{.*}} }
Index: lib/CodeGen/CGStmt.cpp
===================================================================
--- lib/CodeGen/CGStmt.cpp
+++ lib/CodeGen/CGStmt.cpp
@@ -1884,6 +1884,12 @@
           ResultRegDests, AsmString, S.getNumOutputs());
       SawAsmBlock = true;
     }
+
+    // If the assembly contains any labels, mark the function noinline. Inlining
+    // it could cause the callee to contain the same ASM label twice (PR23715).
+    // This is pretty hacky, but it works.
+    if (AsmString.find("__MSASMLABEL_") != std::string::npos)
+      CurFn->addFnAttr(llvm::Attribute::NoInline);
   }
 
   for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {


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