[PATCH] D17853: Disable tail-call optimization for X86 interrupt handlers

[Amjad Aboud via cfe-commits]

aaboud created this revision.
aaboud added reviewers: hjl.tools, DavidKreitzer, ABataev.
aaboud added a subscriber: cfe-commits.

Resolved Bug 26414.
https://llvm.org/bugs/show_bug.cgi?id=26414

Since interrupt handler must be returned with iretq, tail call can't be used.


http://reviews.llvm.org/D17853

Files:
  lib/CodeGen/CGCall.cpp
  test/CodeGen/attr-x86-interrupt.c

Index: lib/CodeGen/CGCall.cpp
===================================================================
--- lib/CodeGen/CGCall.cpp
+++ lib/CodeGen/CGCall.cpp
@@ -1451,6 +1451,7 @@
 
   const Decl *TargetDecl = CalleeInfo.getCalleeDecl();
 
+  bool HasAnyX86InterruptAttr = false;
   // FIXME: handle sseregparm someday...
   if (TargetDecl) {
     if (TargetDecl->hasAttr<ReturnsTwiceAttr>())
@@ -1488,6 +1489,7 @@
     if (TargetDecl->hasAttr<ReturnsNonNullAttr>())
       RetAttrs.addAttribute(llvm::Attribute::NonNull);
 
+    HasAnyX86InterruptAttr = TargetDecl->hasAttr<AnyX86InterruptAttr>();
     HasOptnone = TargetDecl->hasAttr<OptimizeNoneAttr>();
   }
 
@@ -1527,10 +1529,11 @@
     }
 
     bool DisableTailCalls =
-        CodeGenOpts.DisableTailCalls ||
+        CodeGenOpts.DisableTailCalls || HasAnyX86InterruptAttr ||
         (TargetDecl && TargetDecl->hasAttr<DisableTailCallsAttr>());
-    FuncAttrs.addAttribute("disable-tail-calls",
-                           llvm::toStringRef(DisableTailCalls));
+    FuncAttrs.addAttribute(
+        "disable-tail-calls",
+        llvm::toStringRef(DisableTailCalls));
 
     FuncAttrs.addAttribute("less-precise-fpmad",
                            llvm::toStringRef(CodeGenOpts.LessPreciseFPMAD));
Index: test/CodeGen/attr-x86-interrupt.c
===================================================================
--- test/CodeGen/attr-x86-interrupt.c
+++ test/CodeGen/attr-x86-interrupt.c
@@ -15,12 +15,20 @@
 // X86_64_LINUX: @llvm.used = appending global [2 x i8*] [i8* bitcast (void (i32*, i64)* @foo7 to i8*), i8* bitcast (void (i32*)* @foo8 to i8*)], section "llvm.metadata"
 // X86_64_LINUX: define x86_intrcc void @foo7(i32* %{{.+}}, i64 %{{.+}})
 // X86_64_LINUX: define x86_intrcc void @foo8(i32* %{{.+}})
+// X86_64_LINUX: "disable-tail-calls"="true"
+// X86_64_LINUX-NOT: "disable-tail-calls"="false"
 // X86_LINUX: @llvm.used = appending global [2 x i8*] [i8* bitcast (void (i32*, i32)* @foo7 to i8*), i8* bitcast (void (i32*)* @foo8 to i8*)], section "llvm.metadata"
 // X86_LINUX: define x86_intrcc void @foo7(i32* %{{.+}}, i32 %{{.+}})
 // X86_LINUX: define x86_intrcc void @foo8(i32* %{{.+}})
+// X86_LINUX: "disable-tail-calls"="true"
+// X86_LINUX-NOT: "disable-tail-calls"="false"
 // X86_64_WIN: @llvm.used = appending global [2 x i8*] [i8* bitcast (void (i32*, i64)* @foo7 to i8*), i8* bitcast (void (i32*)* @foo8 to i8*)], section "llvm.metadata"
 // X86_64_WIN: define x86_intrcc void @foo7(i32* %{{.+}}, i64 %{{.+}})
 // X86_64_WIN: define x86_intrcc void @foo8(i32* %{{.+}})
+// X86_64_Win: "disable-tail-calls"="true"
+// X86_64_Win-NOT: "disable-tail-calls"="false"
 // X86_WIN: @llvm.used = appending global [2 x i8*] [i8* bitcast (void (i32*, i32)* @foo7 to i8*), i8* bitcast (void (i32*)* @foo8 to i8*)], section "llvm.metadata"
 // X86_WIN: define x86_intrcc void @foo7(i32* %{{.+}}, i32 %{{.+}})
 // X86_WIN: define x86_intrcc void @foo8(i32* %{{.+}})
+// X86_Win: "disable-tail-calls"="true"
+// X86_Win-NOT: "disable-tail-calls"="false"


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