3 files changed, 226 insertions, 4 deletions
diff --git a/llvm/test/CodeGen/X86/musttail-indirect.ll b/llvm/test/CodeGen/X86/musttail-indirect.ll
new file mode 100644
index 00000000000..9d21b5ea5d5
--- /dev/null
+++ b/llvm/test/CodeGen/X86/musttail-indirect.ll
@@ -0,0 +1,124 @@
+; RUN: llc < %s -mtriple=i686-win32 | FileCheck %s
+; RUN: llc < %s -mtriple=i686-win32 -O0 | FileCheck %s
+
+; IR simplified from the following C++ snippet compiled for i686-windows-msvc:
+
+; struct A { A(); ~A(); int a; };
+;
+; struct B {
+;   virtual int  f(int);
+;   virtual int  g(A, int, A);
+;   virtual void h(A, int, A);
+;   virtual A    i(A, int, A);
+;   virtual A    j(int);
+; };
+;
+; int  (B::*mp_f)(int)       = &B::f;
+; int  (B::*mp_g)(A, int, A) = &B::g;
+; void (B::*mp_h)(A, int, A) = &B::h;
+; A    (B::*mp_i)(A, int, A) = &B::i;
+; A    (B::*mp_j)(int)       = &B::j;
+
+; Each member pointer creates a thunk.  The ones with inalloca are required to
+; tail calls by the ABI, even at O0.
+
+%struct.B = type { i32 (...)** }
+%struct.A = type { i32 }
+
+; CHECK-LABEL: f_thunk:
+; CHECK: jmpl
+; CHECK-NOT: ret
+define x86_thiscallcc i32 @f_thunk(%struct.B* %this, i32) {
+entry:
+  %1 = bitcast %struct.B* %this to i32 (%struct.B*, i32)***
+  %vtable = load i32 (%struct.B*, i32)*** %1
+  %2 = load i32 (%struct.B*, i32)** %vtable
+  %3 = musttail call x86_thiscallcc i32 %2(%struct.B* %this, i32 %0)
+  ret i32 %3
+}
+
+; Inalloca thunks shouldn't require any stores to the stack.
+; CHECK-LABEL: g_thunk:
+; CHECK-NOT: mov %{{.*}}, {{.*(.*esp.*)}}
+; CHECK: jmpl
+; CHECK-NOT: ret
+define x86_thiscallcc i32 @g_thunk(%struct.B* %this, <{ %struct.A, i32, %struct.A }>* inalloca) {
+entry:
+  %1 = bitcast %struct.B* %this to i32 (%struct.B*, <{ %struct.A, i32, %struct.A }>*)***
+  %vtable = load i32 (%struct.B*, <{ %struct.A, i32, %struct.A }>*)*** %1
+  %vfn = getelementptr inbounds i32 (%struct.B*, <{ %struct.A, i32, %struct.A }>*)** %vtable, i32 1
+  %2 = load i32 (%struct.B*, <{ %struct.A, i32, %struct.A }>*)** %vfn
+  %3 = musttail call x86_thiscallcc i32 %2(%struct.B* %this, <{ %struct.A, i32, %struct.A }>* inalloca %0)
+  ret i32 %3
+}
+
+; CHECK-LABEL: h_thunk:
+; CHECK: jmpl
+; CHECK-NOT: mov %{{.*}}, {{.*(.*esp.*)}}
+; CHECK-NOT: ret
+define x86_thiscallcc void @h_thunk(%struct.B* %this, <{ %struct.A, i32, %struct.A }>* inalloca) {
+entry:
+  %1 = bitcast %struct.B* %this to void (%struct.B*, <{ %struct.A, i32, %struct.A }>*)***
+  %vtable = load void (%struct.B*, <{ %struct.A, i32, %struct.A }>*)*** %1
+  %vfn = getelementptr inbounds void (%struct.B*, <{ %struct.A, i32, %struct.A }>*)** %vtable, i32 2
+  %2 = load void (%struct.B*, <{ %struct.A, i32, %struct.A }>*)** %vfn
+  musttail call x86_thiscallcc void %2(%struct.B* %this, <{ %struct.A, i32, %struct.A }>* inalloca %0)
+  ret void
+}
+
+; CHECK-LABEL: i_thunk:
+; CHECK-NOT: mov %{{.*}}, {{.*(.*esp.*)}}
+; CHECK: jmpl
+; CHECK-NOT: ret
+define x86_thiscallcc %struct.A* @i_thunk(%struct.B* %this, <{ %struct.A*, %struct.A, i32, %struct.A }>* inalloca) {
+entry:
+  %1 = bitcast %struct.B* %this to %struct.A* (%struct.B*, <{ %struct.A*, %struct.A, i32, %struct.A }>*)***
+  %vtable = load %struct.A* (%struct.B*, <{ %struct.A*, %struct.A, i32, %struct.A }>*)*** %1
+  %vfn = getelementptr inbounds %struct.A* (%struct.B*, <{ %struct.A*, %struct.A, i32, %struct.A }>*)** %vtable, i32 3
+  %2 = load %struct.A* (%struct.B*, <{ %struct.A*, %struct.A, i32, %struct.A }>*)** %vfn
+  %3 = musttail call x86_thiscallcc %struct.A* %2(%struct.B* %this, <{ %struct.A*, %struct.A, i32, %struct.A }>* inalloca %0)
+  ret %struct.A* %3
+}
+
+; CHECK-LABEL: j_thunk:
+; CHECK: jmpl
+; CHECK-NOT: ret
+define x86_thiscallcc void @j_thunk(%struct.A* noalias sret %agg.result, %struct.B* %this, i32) {
+entry:
+  %1 = bitcast %struct.B* %this to void (%struct.A*, %struct.B*, i32)***
+  %vtable = load void (%struct.A*, %struct.B*, i32)*** %1
+  %vfn = getelementptr inbounds void (%struct.A*, %struct.B*, i32)** %vtable, i32 4
+  %2 = load void (%struct.A*, %struct.B*, i32)** %vfn
+  musttail call x86_thiscallcc void %2(%struct.A* sret %agg.result, %struct.B* %this, i32 %0)
+  ret void
+}
+
+; CHECK-LABEL: _stdcall_thunk@8:
+; CHECK-NOT: mov %{{.*}}, {{.*(.*esp.*)}}
+; CHECK: jmpl
+; CHECK-NOT: ret
+define x86_stdcallcc i32 @stdcall_thunk(<{ %struct.B*, %struct.A }>* inalloca) {
+entry:
+  %this_ptr = getelementptr inbounds <{ %struct.B*, %struct.A }>* %0, i32 0, i32 0
+  %this = load %struct.B** %this_ptr
+  %1 = bitcast %struct.B* %this to i32 (<{ %struct.B*, %struct.A }>*)***
+  %vtable = load i32 (<{ %struct.B*, %struct.A }>*)*** %1
+  %vfn = getelementptr inbounds i32 (<{ %struct.B*, %struct.A }>*)** %vtable, i32 1
+  %2 = load i32 (<{ %struct.B*, %struct.A }>*)** %vfn
+  %3 = musttail call x86_stdcallcc i32 %2(<{ %struct.B*, %struct.A }>* inalloca %0)
+  ret i32 %3
+}
+
+; CHECK-LABEL: @fastcall_thunk@8:
+; CHECK-NOT: mov %{{.*}}, {{.*(.*esp.*)}}
+; CHECK: jmpl
+; CHECK-NOT: ret
+define x86_fastcallcc i32 @fastcall_thunk(%struct.B* inreg %this, <{ %struct.A }>* inalloca) {
+entry:
+  %1 = bitcast %struct.B* %this to i32 (%struct.B*, <{ %struct.A }>*)***
+  %vtable = load i32 (%struct.B*, <{ %struct.A }>*)*** %1
+  %vfn = getelementptr inbounds i32 (%struct.B*, <{ %struct.A }>*)** %vtable, i32 1
+  %2 = load i32 (%struct.B*, <{ %struct.A }>*)** %vfn
+  %3 = musttail call x86_fastcallcc i32 %2(%struct.B* inreg %this, <{ %struct.A }>* inalloca %0)
+  ret i32 %3
+}
diff --git a/llvm/test/CodeGen/X86/musttail-thiscall.ll b/llvm/test/CodeGen/X86/musttail-thiscall.ll
new file mode 100644
index 00000000000..8ea12482e50
--- /dev/null
+++ b/llvm/test/CodeGen/X86/musttail-thiscall.ll
@@ -0,0 +1,31 @@
+; RUN: llc -march=x86 < %s | FileCheck %s
+; RUN: llc -march=x86 -O0 < %s | FileCheck %s
+
+; CHECK-LABEL: t1:
+; CHECK: jmp {{_?}}t1_callee
+define x86_thiscallcc void @t1(i8* %this) {
+  %adj = getelementptr i8* %this, i32 4
+  musttail call x86_thiscallcc void @t1_callee(i8* %adj)
+  ret void
+}
+declare x86_thiscallcc void @t1_callee(i8* %this)
+
+; CHECK-LABEL: t2:
+; CHECK: jmp {{_?}}t2_callee
+define x86_thiscallcc i32 @t2(i8* %this, i32 %a) {
+  %adj = getelementptr i8* %this, i32 4
+  %rv = musttail call x86_thiscallcc i32 @t2_callee(i8* %adj, i32 %a)
+  ret i32 %rv
+}
+declare x86_thiscallcc i32 @t2_callee(i8* %this, i32 %a)
+
+; CHECK-LABEL: t3:
+; CHECK: jmp {{_?}}t3_callee
+define x86_thiscallcc i8* @t3(i8* %this, <{ i8*, i32 }>* inalloca %args) {
+  %adj = getelementptr i8* %this, i32 4
+  %a_ptr = getelementptr <{ i8*, i32 }>* %args, i32 0, i32 1
+  store i32 0, i32* %a_ptr
+  %rv = musttail call x86_thiscallcc i8* @t3_callee(i8* %adj, <{ i8*, i32 }>* inalloca %args)
+  ret i8* %rv
+}
+declare x86_thiscallcc i8* @t3_callee(i8* %this, <{ i8*, i32 }>* inalloca %args);
diff --git a/llvm/test/CodeGen/X86/musttail.ll b/llvm/test/CodeGen/X86/musttail.ll
index 75b217f9947..ca5d3119cf1 100644
--- a/llvm/test/CodeGen/X86/musttail.ll
+++ b/llvm/test/CodeGen/X86/musttail.ll
@@ -1,8 +1,6 @@
 ; RUN: llc -march=x86 < %s | FileCheck %s
-
-; FIXME: Eliminate this tail call at -O0, since musttail is a correctness
-; requirement.
-; RUN: not llc -march=x86 -O0 < %s
+; RUN: llc -march=x86 -O0 < %s | FileCheck %s
+; RUN: llc -march=x86 -disable-tail-calls < %s | FileCheck %s
 
 declare void @t1_callee(i8*)
 define void @t1(i32* %a) {
@@ -21,3 +19,72 @@ define i32* @t2() {
   %w = bitcast i8* %v to i32*
   ret i32* %w
 }
+
+; Complex frame layout: stack realignment with dynamic alloca.
+define void @t3(i32 %n) alignstack(32) nounwind {
+entry:
+; CHECK: t3:
+; CHECK: pushl %ebp
+; CHECK: pushl %esi
+; CHECK: andl $-32, %esp
+; CHECK: movl %esp, %esi
+; CHECK: popl %esi
+; CHECK: popl %ebp
+; CHECK-NEXT: jmp {{_?}}t3_callee
+  %a = alloca i8, i32 %n
+  call void @capture(i8* %a)
+  musttail call void @t3_callee(i32 %n) nounwind
+  ret void
+}
+
+declare void @capture(i8*)
+declare void @t3_callee(i32)
+
+; Test that we actually copy in and out stack arguments that aren't forwarded
+; without modification.
+define i32 @t4({}* %fn, i32 %n, i32 %r) {
+; CHECK-LABEL: t4:
+; CHECK: incl %[[r:.*]]
+; CHECK: decl %[[n:.*]]
+; CHECK: movl %[[r]], {{[0-9]+}}(%esp)
+; CHECK: movl %[[n]], {{[0-9]+}}(%esp)
+; CHECK: jmpl *%{{.*}}
+
+entry:
+  %r1 = add i32 %r, 1
+  %n1 = sub i32 %n, 1
+  %fn_cast = bitcast {}* %fn to i32 ({}*, i32, i32)*
+  %r2 = musttail call i32 %fn_cast({}* %fn, i32 %n1, i32 %r1)
+  ret i32 %r2
+}
+
+; Combine the complex stack frame with the parameter modification.
+define i32 @t5({}* %fn, i32 %n, i32 %r) alignstack(32) {
+; CHECK-LABEL: t5:
+; CHECK: pushl %ebp
+; CHECK: movl %esp, %ebp
+; CHECK: pushl %esi
+; 	Align the stack.
+; CHECK: andl $-32, %esp
+; CHECK: movl %esp, %esi
+; 	Modify the args.
+; CHECK: incl %[[r:.*]]
+; CHECK: decl %[[n:.*]]
+; 	Store them through ebp, since that's the only stable arg pointer.
+; CHECK: movl %[[r]], {{[0-9]+}}(%ebp)
+; CHECK: movl %[[n]], {{[0-9]+}}(%ebp)
+; 	Epilogue.
+; CHECK: leal {{[-0-9]+}}(%ebp), %esp
+; CHECK: popl %esi
+; CHECK: popl %ebp
+; CHECK: jmpl *%{{.*}}
+
+entry:
+  %a = alloca i8, i32 %n
+  call void @capture(i8* %a)
+  %r1 = add i32 %r, 1
+  %n1 = sub i32 %n, 1
+  %fn_cast = bitcast {}* %fn to i32 ({}*, i32, i32)*
+  %r2 = musttail call i32 %fn_cast({}* %fn, i32 %n1, i32 %r1)
+  ret i32 %r2
+}