[MSan] [Mips64] Add tests for vararg handling.

[• koriakin]

Summary

These are the tests requested in D19292.

[• koriakin]

Ugh... while these tests are correct, I just noticed Mips assumes there's exactly one argument before the ... in arument list, and breaks hopelessly if that's not true. x86_64 is also broken, but less so - it assumes all arguments before ... fit in registers (ie. 6 ints/pointers, plus some floats). I haven't looked into AArch64 yet, but I suspect the same issue as x86_64.

[aizatsky]

I'm not sure what does "-el" mean in "vararg-el.ll". Can you pick a more descriptive suffix? Or add a comment to the test describing the difference from "vararg.ll".

[• koriakin]

In D19919#421313, @koriakin wrote:

Ugh... while these tests are correct, I just noticed Mips assumes there's exactly one argument before the ... in arument list, and breaks hopelessly if that's not true. x86_64 is also broken, but less so - it assumes all arguments before ... fit in registers (ie. 6 ints/pointers, plus some floats). I haven't looked into AArch64 yet, but I suspect the same issue as x86_64.

Issue reported at https://llvm.org/bugs/show_bug.cgi?id=27646 . I'll attempt to fix it for Mips64 and PowerPC64.

[sdardis]

It's short for little endian.

[• koriakin]

In D19919#421346, @aizatsky wrote:

I'm not sure what does "-el" mean in "vararg-el.ll". Can you pick a more descriptive suffix? Or add a comment to the test describing the difference from "vararg.ll".

It's for mips64el (little-endian variant). I'll change the names to vararg-mips64.ll and vararg-mips64el.ll .

test/Instrumentation/MemorySanitizer/Mips/vararg-el.ll

+; RUN: opt < %s -msan -S | FileCheck %s
+
+target datalayout = "e-m:m-i8:8:32-i16:16:32-i64:64-n32:64-S128"
+target triple = "mips64el--linux"
+
+define i32 @foo(i32 %guard, ...) {
+  %vl = alloca i8*, align 8
+  %1 = bitcast i8** %vl to i8*
+  call void @llvm.lifetime.start(i64 32, i8* %1)
+  call void @llvm.va_start(i8* %1)
+  call void @llvm.va_end(i8* %1)
+  call void @llvm.lifetime.end(i64 32, i8* %1)
+  ret i32 0
+}
+
+; First, check allocation of the save area.
+
+; CHECK-LABEL: @foo
+; CHECK: [[A:%.*]] = load {{.*}} @__msan_va_arg_overflow_size_tls
+; CHECK: [[B:%.*]] = add i64 0, [[A]]
+; CHECK: [[C:%.*]] = alloca {{.*}} [[B]]
+
+; CHECK: [[STACK:%.*]] = bitcast {{.*}} @__msan_va_arg_tls to i8*
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[C]], i8* [[STACK]], i64 [[B]], i32 8, i1 false)
+
+declare void @llvm.lifetime.start(i64, i8* nocapture) #1
+declare void @llvm.va_start(i8*) #2
+declare void @llvm.va_end(i8*) #2
+declare void @llvm.lifetime.end(i64, i8* nocapture) #1
+
+define i32 @bar() {
+  %1 = call i32 (i32, ...) @foo(i32 0, i32 1, i64 2, double 3.000000e+00)
+  ret i32 %1
+}
+
+; Save the incoming shadow value from the arguments in the __msan_va_arg_tls
+; array.
+; CHECK-LABEL: @bar
+; CHECK: store i32 0, i32* bitcast ([100 x i64]* @__msan_va_arg_tls to i32*), align 8
+; CHECK: store i64 0, i64* inttoptr (i64 add (i64 ptrtoint ([100 x i64]* @__msan_va_arg_tls to i64), i64 8) to i64*), align 8
+; CHECK: store i64 0, i64* inttoptr (i64 add (i64 ptrtoint ([100 x i64]* @__msan_va_arg_tls to i64), i64 16) to i64*), align 8
+; CHECK: store {{.*}} 24, {{.*}} @__msan_va_arg_overflow_size_tls

test/Instrumentation/MemorySanitizer/Mips/vararg.ll

+; RUN: opt < %s -msan -S | FileCheck %s
+
+target datalayout = "E-m:m-i8:8:32-i16:16:32-i64:64-n32:64-S128"
+target triple = "mips64--linux"
+
+define i32 @foo(i32 %guard, ...) {
+  %vl = alloca i8*, align 8
+  %1 = bitcast i8** %vl to i8*
+  call void @llvm.lifetime.start(i64 32, i8* %1)
+  call void @llvm.va_start(i8* %1)
+  call void @llvm.va_end(i8* %1)
+  call void @llvm.lifetime.end(i64 32, i8* %1)
+  ret i32 0
+}
+
+; First, check allocation of the save area.
+
+; CHECK-LABEL: @foo
+; CHECK: [[A:%.*]] = load {{.*}} @__msan_va_arg_overflow_size_tls
+; CHECK: [[B:%.*]] = add i64 0, [[A]]
+; CHECK: [[C:%.*]] = alloca {{.*}} [[B]]
+
+; CHECK: [[STACK:%.*]] = bitcast {{.*}} @__msan_va_arg_tls to i8*
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[C]], i8* [[STACK]], i64 [[B]], i32 8, i1 false)
+
+declare void @llvm.lifetime.start(i64, i8* nocapture) #1
+declare void @llvm.va_start(i8*) #2
+declare void @llvm.va_end(i8*) #2
+declare void @llvm.lifetime.end(i64, i8* nocapture) #1
+
+define i32 @bar() {
+  %1 = call i32 (i32, ...) @foo(i32 0, i32 1, i64 2, double 3.000000e+00)
+  ret i32 %1
+}
+
+; Save the incoming shadow value from the arguments in the __msan_va_arg_tls
+; array.  The first argument is stored at position 4, since it's right
+; justified.
+; CHECK-LABEL: @bar
+; CHECK: store i32 0, i32* inttoptr (i64 add (i64 ptrtoint ([100 x i64]* @__msan_va_arg_tls to i64), i64 4) to i32*), align 8
+; CHECK: store i64 0, i64* inttoptr (i64 add (i64 ptrtoint ([100 x i64]* @__msan_va_arg_tls to i64), i64 8) to i64*), align 8
+; CHECK: store i64 0, i64* inttoptr (i64 add (i64 ptrtoint ([100 x i64]* @__msan_va_arg_tls to i64), i64 16) to i64*), align 8
+; CHECK: store {{.*}} 24, {{.*}} @__msan_va_arg_overflow_size_tls