Allow alias to point to an arbitrary ConstantExpr.

This  patch changes GlobalAlias to point to an arbitrary ConstantExpr and it is
up to MC (or the system assembler) to decide if that expression is valid or not.

This reduces our ability to diagnose invalid uses and how early we can spot
them, but it also lets us do things like

@test5 = alias inttoptr(i32 sub (i32 ptrtoint (i32* @test2 to i32),
                                 i32 ptrtoint (i32* @bar to i32)) to i32*)

An important implication of this patch is that the notion of aliased global
doesn't exist any more. The alias has to encode the information needed to
access it in its metadata (linkage, visibility, type, etc).

Another consequence to notice is that getSection has to return a "const char *".
It could return a NullTerminatedStringRef if there was such a thing, but when
that was proposed the decision was to just uses "const char*" for that.

llvm-svn: 210062

22 files changed, 88 insertions, 75 deletions

diff --git a/llvm/test/Assembler/addrspacecast-alias.ll b/llvm/test/Assembler/addrspacecast-alias.ll
index 052a1414eab..7d00ac4f8f3 100644
--- a/llvm/test/Assembler/addrspacecast-alias.ll
+++ b/llvm/test/Assembler/addrspacecast-alias.ll
@@ -3,5 +3,5 @@
 ; Test that global aliases are allowed to be constant addrspacecast
 
 @i = internal addrspace(1) global i8 42
-@ia = alias internal addrspace(2) i8 addrspace(3)*, i8 addrspace(1)* @i
-; CHECK: @ia = alias internal addrspace(2) i8 addrspace(3)*, i8 addrspace(1)* @i
+@ia = alias internal addrspacecast (i8 addrspace(1)* @i to i8 addrspace(2)* addrspace(3)*)
+; CHECK: @ia =  alias internal addrspacecast (i8 addrspace(1)* @i to i8 addrspace(2)* addrspace(3)*)
diff --git a/llvm/test/Assembler/alias-addrspace.ll b/llvm/test/Assembler/alias-addrspace.ll
deleted file mode 100644
index 6d378e45fa2..00000000000
--- a/llvm/test/Assembler/alias-addrspace.ll
+++ /dev/null
@@ -1,6 +0,0 @@
-; RUN: not llvm-as %s 2>&1 | FileCheck %s
-
-@foo = global i32 42
-@bar = alias internal addrspace(1) i32* @foo
-
-CHECK: error: A type is required if addrspace is given
diff --git a/llvm/test/Assembler/alias-to-alias.ll b/llvm/test/Assembler/alias-to-alias.ll
deleted file mode 100644
index 1ea99bbb694..00000000000
--- a/llvm/test/Assembler/alias-to-alias.ll
+++ /dev/null
@@ -1,5 +0,0 @@
-; RUN:  not llvm-as %s -o /dev/null 2>&1 | FileCheck %s
-; CHECK: Alias must point to function or variable
-
-@b1 = alias i32* @c1
-@c1 = alias i32* @b1
diff --git a/llvm/test/Assembler/alias-to-alias2.ll b/llvm/test/Assembler/alias-to-alias2.ll
deleted file mode 100644
index a8a0196f436..00000000000
--- a/llvm/test/Assembler/alias-to-alias2.ll
+++ /dev/null
@@ -1,7 +0,0 @@
-; RUN:  not llvm-as %s -o /dev/null 2>&1 | FileCheck %s
-; CHECK: error: Alias is pointed by alias b1
-
-@g = global i32 42
-
-@b1 = alias i32* @c1
-@c1 = alias i32* @g
diff --git a/llvm/test/Assembler/alias-type.ll b/llvm/test/Assembler/alias-type.ll
deleted file mode 100644
index ead3e95243f..00000000000
--- a/llvm/test/Assembler/alias-type.ll
+++ /dev/null
@@ -1,6 +0,0 @@
-; RUN: not llvm-as %s 2>&1 | FileCheck %s
-
-@foo = global i32 42
-@bar = alias i32 @foo
-
-CHECK: error: An alias must have pointer type
diff --git a/llvm/test/Bitcode/old-aliases.ll b/llvm/test/Bitcode/old-aliases.ll
index 4ef47c03dd7..7a0eea2f3f2 100644
--- a/llvm/test/Bitcode/old-aliases.ll
+++ b/llvm/test/Bitcode/old-aliases.ll
@@ -10,13 +10,13 @@
 ; CHECK: @v2 = global [1 x i32] zeroinitializer
 
 @v3 = alias bitcast (i32* @v1 to i16*)
-; CHECK: @v3 = alias i16, i32* @v1
+; CHECK: @v3 = alias bitcast (i32* @v1 to i16*)
 
 @v4 = alias getelementptr ([1 x i32]* @v2, i32 0, i32 0)
-; CHECK: @v4 = alias i32, [1 x i32]* @v2
+; CHECK: @v4 = alias getelementptr inbounds ([1 x i32]* @v2, i32 0, i32 0)
 
 @v5 = alias i32 addrspace(2)* addrspacecast (i32 addrspace(0)* @v1 to i32 addrspace(2)*)
-; CHECK: @v5 = alias addrspace(2) i32, i32* @v1
+; CHECK: @v5 = alias addrspacecast (i32* @v1 to i32 addrspace(2)*)
 
 @v6 = alias i16* @v3
-; CHECK: @v6 = alias i16, i32* @v1
+; CHECK: @v6 = alias i16* @v3
diff --git a/llvm/test/CodeGen/ARM/aliases.ll b/llvm/test/CodeGen/ARM/aliases.ll
index 4de305b93bd..f55ae10b247 100644
--- a/llvm/test/CodeGen/ARM/aliases.ll
+++ b/llvm/test/CodeGen/ARM/aliases.ll
@@ -29,7 +29,7 @@ define i32 @foo_f() {
 
 @bar_i = alias internal i32* @bar
 
-@A = alias i64, i32* @bar
+@A = alias bitcast (i32* @bar to i64*)
 
 define i32 @test() {
 entry:
diff --git a/llvm/test/CodeGen/X86/aliases.ll b/llvm/test/CodeGen/X86/aliases.ll
index d207880d660..bf55644de41 100644
--- a/llvm/test/CodeGen/X86/aliases.ll
+++ b/llvm/test/CodeGen/X86/aliases.ll
@@ -38,7 +38,7 @@ define i32 @foo_f() {
 @bar_i = alias internal i32* @bar
 
 ; CHECK-DAG: .globl	A
-@A = alias i64, i32* @bar
+@A = alias bitcast (i32* @bar to i64*)
 
 ; CHECK-DAG: .globl	bar_h
 ; CHECK-DAG: .hidden	bar_h
@@ -48,6 +48,19 @@ define i32 @foo_f() {
 ; CHECK-DAG: .protected	bar_p
 @bar_p = protected alias i32* @bar
 
+; CHECK-DAG: test2 = bar+4
+@test2 = alias getelementptr(i32 *@bar, i32 1)
+
+; CHECK-DAG: test3 = 42
+@test3 = alias inttoptr(i32 42 to i32*)
+
+; CHECK-DAG: test4 = bar
+@test4 = alias inttoptr(i64 ptrtoint (i32* @bar to i64) to i32*)
+
+; CHECK-DAG: test5 = test2-bar
+@test5 = alias inttoptr(i32 sub (i32 ptrtoint (i32* @test2 to i32),
+                                 i32 ptrtoint (i32* @bar to i32)) to i32*)
+
 ; CHECK-DAG: .globl	test
 define i32 @test() {
 entry:
diff --git a/llvm/test/CodeGen/X86/dllexport-x86_64.ll b/llvm/test/CodeGen/X86/dllexport-x86_64.ll
index f4dec4ff591..0d5afa1b138 100644
--- a/llvm/test/CodeGen/X86/dllexport-x86_64.ll
+++ b/llvm/test/CodeGen/X86/dllexport-x86_64.ll
@@ -73,7 +73,7 @@ define weak_odr dllexport void @weak1() {
 @weak_alias = dllexport alias weak_odr void()* @f1
 
 @blob = global [6 x i8] c"\B8*\00\00\00\C3", section ".text", align 16
-@blob_alias = dllexport alias i32 (), [6 x i8]* @blob
+@blob_alias = dllexport alias bitcast ([6 x i8]* @blob to i32 ()*)
 
 ; CHECK: .section .drectve
 ; WIN32: " /EXPORT:Var1,DATA"
diff --git a/llvm/test/Feature/alias2.ll b/llvm/test/Feature/alias2.ll
index bc542ffd770..73c874f2b9e 100644
--- a/llvm/test/Feature/alias2.ll
+++ b/llvm/test/Feature/alias2.ll
@@ -6,17 +6,23 @@
 @v2 = global [1 x i32] zeroinitializer
 ; CHECK: @v2 = global [1 x i32] zeroinitializer
 
-@a1 = alias i16, i32* @v1
-; CHECK: @a1 = alias i16, i32* @v1
+@v3 = global [2 x i16] zeroinitializer
+; CHECK: @v3 = global [2 x i16] zeroinitializer
 
-@a2 = alias i32, [1 x i32]* @v2
-; CHECK: @a2 = alias i32, [1 x i32]* @v2
+@a1 = alias bitcast (i32* @v1 to i16*)
+; CHECK: @a1 = alias bitcast (i32* @v1 to i16*)
 
-@a3 = alias addrspace(2) i32, i32* @v1
-; CHECK: @a3 = alias addrspace(2) i32, i32* @v1
+@a2 = alias bitcast([1 x i32]* @v2 to i32*)
+; CHECK: @a2 = alias getelementptr inbounds ([1 x i32]* @v2, i32 0, i32 0)
 
-@a4 = alias i16, i32* @v1
-; CHECK: @a4 = alias i16, i32* @v1
+@a3 = alias addrspacecast (i32* @v1 to i32 addrspace(2)*)
+; CHECK: @a3 = alias addrspacecast (i32* @v1 to i32 addrspace(2)*)
+
+@a4 = alias bitcast (i32* @v1 to i16*)
+; CHECK: @a4 = alias bitcast (i32* @v1 to i16*)
 
 @a5 = thread_local(localdynamic) alias i32* @v1
 ; CHECK: @a5 = thread_local(localdynamic) alias i32* @v1
+
+@a6 = alias getelementptr ([2 x i16]* @v3, i32 1, i32 1)
+; CHECK: @a6 = alias getelementptr ([2 x i16]* @v3, i32 1, i32 1)
diff --git a/llvm/test/Feature/aliases.ll b/llvm/test/Feature/aliases.ll
index b2ce82a8388..7fe9d0b374e 100644
--- a/llvm/test/Feature/aliases.ll
+++ b/llvm/test/Feature/aliases.ll
@@ -7,6 +7,7 @@
 @bar = global i32 0
 @foo1 = alias i32* @bar
 @foo2 = alias i32* @bar
+@foo3 = alias i32* @foo2
 
 %FunTy = type i32()
 
@@ -14,10 +15,11 @@ define i32 @foo_f() {
   ret i32 0
 }
 @bar_f = alias weak_odr %FunTy* @foo_f
+@bar_ff = alias i32()* @bar_f
 
 @bar_i = alias internal i32* @bar
 
-@A = alias i64, i32* @bar
+@A = alias bitcast (i32* @bar to i64*)
 
 define i32 @test() {
 entry:
diff --git a/llvm/test/Linker/Inputs/PR8300.b.ll b/llvm/test/Linker/Inputs/PR8300.b.ll
index 362d309a191..9e538f5d286 100644
--- a/llvm/test/Linker/Inputs/PR8300.b.ll
+++ b/llvm/test/Linker/Inputs/PR8300.b.ll
@@ -1,7 +1,7 @@
 %foo = type { [8 x i8] }
 %bar = type { [9 x i8] }
 
-@zed = alias void (%foo*), void (%bar*)* @xyz
+@zed = alias bitcast (void (%bar*)* @xyz to void (%foo*)*)
 
 define void @xyz(%bar* %this) {
 entry:
diff --git a/llvm/test/Linker/Inputs/alias.ll b/llvm/test/Linker/Inputs/alias.ll
index b869cae71e3..f379476e765 100644
--- a/llvm/test/Linker/Inputs/alias.ll
+++ b/llvm/test/Linker/Inputs/alias.ll
@@ -1,3 +1,3 @@
 @zed = global i32 42
 @foo = alias i32* @zed
-@foo2 = alias i16, i32* @zed
+@foo2 = alias bitcast (i32* @zed to i16*)
diff --git a/llvm/test/Linker/Inputs/cycle.ll b/llvm/test/Linker/Inputs/cycle.ll
deleted file mode 100644
index d0eddb6e7c0..00000000000
--- a/llvm/test/Linker/Inputs/cycle.ll
+++ /dev/null
@@ -1,2 +0,0 @@
-@foo = alias i32* @bar
-@bar = weak global i32 0
diff --git a/llvm/test/Linker/alias.ll b/llvm/test/Linker/alias.ll
index 5809a150820..bce51ad9836 100644
--- a/llvm/test/Linker/alias.ll
+++ b/llvm/test/Linker/alias.ll
@@ -5,12 +5,12 @@
 ; CHECK-DAG: @foo = alias i32* @zed
 
 @bar = alias i32* @foo
-; CHECK-DAG: @bar = alias i32* @zed
+; CHECK-DAG: @bar = alias i32* @foo
 
 @foo2 = weak global i32 0
-; CHECK-DAG: @foo2 = alias i16, i32* @zed
+; CHECK-DAG: @foo2 = alias bitcast (i32* @zed to i16*)
 
 @bar2 = alias i32* @foo2
-; CHECK-DAG: @bar2 = alias i32* @zed
+; CHECK-DAG: @bar2 = alias bitcast (i16* @foo2 to i32*)
 
 ; CHECK-DAG: @zed = global i32 42
diff --git a/llvm/test/Linker/cycle.ll b/llvm/test/Linker/cycle.ll
deleted file mode 100644
index 7d9ad2d9d6f..00000000000
--- a/llvm/test/Linker/cycle.ll
+++ /dev/null
@@ -1,7 +0,0 @@
-; RUN: not llvm-link %s %S/Inputs/cycle.ll 2>&1 | FileCheck %s
-; RUN: not llvm-link %S/Inputs/cycle.ll %s 2>&1 | FileCheck %s
-
-; CHECK: Linking these modules creates an alias cycle
-
-@foo = weak global i32 0
-@bar = alias i32* @foo
diff --git a/llvm/test/Transforms/GlobalDCE/2009-01-05-DeadAliases.ll b/llvm/test/Transforms/GlobalDCE/2009-01-05-DeadAliases.ll
index 4b967997ce8..0bdced5114d 100644
--- a/llvm/test/Transforms/GlobalDCE/2009-01-05-DeadAliases.ll
+++ b/llvm/test/Transforms/GlobalDCE/2009-01-05-DeadAliases.ll
@@ -11,8 +11,8 @@
 @L1 = alias i32* @A
 ; CHECK: @L1 = alias i32* @A
 
-@L2 = alias internal i32* @A
-; DEAD-NOT: @L2
+@L2 = alias internal i32* @L1
+; CHECK: @L2 = alias internal i32* @L1
 
-@L3 = alias i32* @A
-; CHECK: @L3 = alias i32* @A
+@L3 = alias i32* @L2
+; CHECK: @L3 = alias i32* @L2
diff --git a/llvm/test/Transforms/GlobalOpt/2009-02-15-BitcastAlias.ll b/llvm/test/Transforms/GlobalOpt/2009-02-15-BitcastAlias.ll
index 03d6ee4f8a1..d6a565ad10a 100644
--- a/llvm/test/Transforms/GlobalOpt/2009-02-15-BitcastAlias.ll
+++ b/llvm/test/Transforms/GlobalOpt/2009-02-15-BitcastAlias.ll
@@ -2,7 +2,7 @@
 
 @g = global i32 0
 
-@a = alias i8, i32* @g
+@a = alias bitcast (i32* @g to i8*)
 
 define void @f() {
 	%tmp = load i8* @a
diff --git a/llvm/test/Transforms/GlobalOpt/alias-resolve.ll b/llvm/test/Transforms/GlobalOpt/alias-resolve.ll
index bd07b31b235..2d5a956d14b 100644
--- a/llvm/test/Transforms/GlobalOpt/alias-resolve.ll
+++ b/llvm/test/Transforms/GlobalOpt/alias-resolve.ll
@@ -1,9 +1,9 @@
 ; RUN: opt < %s -globalopt -S | FileCheck %s
 
-@foo1 = alias void ()* @bar2
+@foo1 = alias void ()* @foo2
 ; CHECK: @foo1 = alias void ()* @bar2
 
-@foo2 = alias void()* @bar2
+@foo2 = alias void()* @bar1
 ; CHECK: @foo2 = alias void ()* @bar2
 
 @bar1  = alias void ()* @bar2
diff --git a/llvm/test/Transforms/InstCombine/bitcast-alias-function.ll b/llvm/test/Transforms/InstCombine/bitcast-alias-function.ll
index 284960b1133..a6b56f94ffb 100644
--- a/llvm/test/Transforms/InstCombine/bitcast-alias-function.ll
+++ b/llvm/test/Transforms/InstCombine/bitcast-alias-function.ll
@@ -6,46 +6,46 @@ target datalayout = "e-p:32:32:32-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v16:16
 ; Cases that should be bitcast
 
 ; Test cast between scalars with same bit sizes
-@alias_i32_to_f32 = alias float (float), i32 (i32)* @func_i32
+@alias_i32_to_f32 = alias bitcast (i32 (i32)* @func_i32 to float (float)*)
 
 ; Test cast between vectors with same number of elements and bit sizes
-@alias_v2i32_to_v2f32 = alias <2 x float> (<2 x float>), <2 x i32> (<2 x i32>)* @func_v2i32
+@alias_v2i32_to_v2f32 = alias bitcast (<2 x i32> (<2 x i32>)* @func_v2i32 to <2 x float> (<2 x float>)*)
 
 ; Test cast from vector to scalar with same number of bits
-@alias_v2f32_to_i64 = alias <2 x float> (<2 x float>), i64 (i64)* @func_i64
+@alias_v2f32_to_i64 = alias bitcast (i64 (i64)* @func_i64 to <2 x float> (<2 x float>)*)
 
 ; Test cast from scalar to vector with same number of bits
-@alias_i64_to_v2f32 = alias  i64 (i64), <2 x float> (<2 x float>)* @func_v2f32
+@alias_i64_to_v2f32 = alias bitcast (<2 x float> (<2 x float>)* @func_v2f32 to i64 (i64)*)
 
 ; Test cast between vectors of pointers
-@alias_v2i32p_to_v2i64p = alias <2 x i64*> (<2 x i64*>), <2 x i32*> (<2 x i32*>)* @func_v2i32p
+@alias_v2i32p_to_v2i64p = alias bitcast (<2 x i32*> (<2 x i32*>)* @func_v2i32p to <2 x i64*> (<2 x i64*>)*)
 
 
 ; Cases that should be invalid and unchanged
 
 ; Test cast between scalars with different bit sizes
-@alias_i64_to_f32 = alias float (float), i64 (i64)* @func_i64
+@alias_i64_to_f32 = alias bitcast (i64 (i64)* @func_i64 to float (float)*)
 
 ; Test cast between vectors with different bit sizes but the
 ; same number of elements
-@alias_v2i64_to_v2f32 = alias <2 x float> (<2 x float>), <2 x i64> (<2 x i64>)* @func_v2i64
+@alias_v2i64_to_v2f32 = alias bitcast (<2 x i64> (<2 x i64>)* @func_v2i64 to <2 x float> (<2 x float>)*)
 
 ; Test cast between vectors with same number of bits and different
 ; numbers of elements
-@alias_v2i32_to_v4f32 = alias  <4 x float> (<4 x float>), <2 x i32> (<2 x i32>)* @func_v2i32
+@alias_v2i32_to_v4f32 = alias bitcast (<2 x i32> (<2 x i32>)* @func_v2i32 to <4 x float> (<4 x float>)*)
 
 ; Test cast between scalar and vector with different number of bits
-@alias_i64_to_v4f32 = alias i64 (i64), <4 x float> (<4 x float>)* @func_v4f32
+@alias_i64_to_v4f32 = alias bitcast (<4 x float> (<4 x float>)* @func_v4f32 to i64 (i64)*)
 
 ; Test cast between vector and scalar with different number of bits
-@alias_v4f32_to_i64 = alias <4 x float> (<4 x float>), i64 (i64)* @func_i64
+@alias_v4f32_to_i64 = alias bitcast (i64 (i64)* @func_i64 to <4 x float> (<4 x float>)*)
 
 ; Test cast from scalar to vector of pointers with same number of bits
 ; We don't know the pointer size at this point, so this can't be done
-@alias_i64_to_v2i32p = alias  i64 (i64), <2 x i32*> (<2 x i32*>)* @func_v2i32p
+@alias_i64_to_v2i32p = alias bitcast (<2 x i32*> (<2 x i32*>)* @func_v2i32p to i64 (i64)*)
 
 ; Test cast between vector of pointers and scalar with different number of bits
-@alias_v4i32p_to_i64 = alias <4 x i32*> (<4 x i32*>), i64 (i64)* @func_i64
+@alias_v4i32p_to_i64 = alias bitcast (i64 (i64)* @func_i64 to <4 x i32*> (<4 x i32*>)*)
 
 
 
diff --git a/llvm/test/Verifier/alias.ll b/llvm/test/Verifier/alias.ll
index e3636bc7017..ff02a37bab9 100644
--- a/llvm/test/Verifier/alias.ll
+++ b/llvm/test/Verifier/alias.ll
@@ -10,3 +10,18 @@ declare void @f()
 @ga = alias i32* @g
 ; CHECK: Alias must point to a definition
 ; CHECK-NEXT: @ga
+
+
+@test2_a = alias i32* @test2_b
+@test2_b = alias i32* @test2_a
+; CHECK:      Aliases cannot form a cycle
+; CHECK-NEXT: i32* @test2_a
+; CHECK-NEXT: Aliases cannot form a cycle
+; CHECK-NEXT: i32* @test2_b
+
+
+@test3_a = global i32 42
+@test3_b = alias weak i32* @test3_a
+@test3_c = alias i32* @test3_b
+; CHECK: Alias cannot point to a weak alias
+; CHECK-NEXT: i32* @test3_c
diff --git a/llvm/test/Verifier/bitcast-alias-address-space.ll b/llvm/test/Verifier/bitcast-alias-address-space.ll
new file mode 100644
index 00000000000..d9794d9e338
--- /dev/null
+++ b/llvm/test/Verifier/bitcast-alias-address-space.ll
@@ -0,0 +1,10 @@
+; RUN: not llvm-as -disable-output %s 2>&1 | FileCheck %s
+
+; CHECK: error: invalid cast opcode for cast from 'i32 addrspace(2)*' to 'i32 addrspace(1)*'
+
+target datalayout = "e-p:32:32:32-p1:16:16:16-p2:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:32:64-v128:32:128-a0:0:32-n8:16:32"
+
+
+@data = addrspace(2) global i32 27
+
+@illegal_alias_data = alias bitcast (i32 addrspace(2)* @data to i32 addrspace(1)*)