[llvm] r364985 - [WebAssembly] Prevent inline assembly from being mangled by SjLj
Guanzhong Chen via llvm-commits
llvm-commits at lists.llvm.org
Tue Jul 2 17:37:49 PDT 2019
Author: quantum
Date: Tue Jul 2 17:37:49 2019
New Revision: 364985
URL: http://llvm.org/viewvc/llvm-project?rev=364985&view=rev
Log:
[WebAssembly] Prevent inline assembly from being mangled by SjLj
Summary:
Before, inline assembly gets mangled by the SjLj transformation.
For example, in a function with setjmp/longjmp, this LLVM IR code
call void asm sideeffect "", ""()
would be transformed into
call void @__invoke_void(void ()* asm sideeffect "", "")
This is invalid, and results in the error:
Cannot take the address of an inline asm!
In this diff, we skip the transformation for inline assembly.
Reviewers: aheejin, tlively
Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64115
Modified:
llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll
Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp?rev=364985&r1=364984&r2=364985&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp (original)
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp Tue Jul 2 17:37:49 2019
@@ -485,6 +485,13 @@ bool WebAssemblyLowerEmscriptenEHSjLj::c
if (CalleeF->isIntrinsic())
return false;
+ // Attempting to transform inline assembly will result in something like:
+ // call void @__invoke_void(void ()* asm ...)
+ // which is invalid because inline assembly blocks do not have addresses
+ // and can't be passed by pointer. The result is a crash with illegal IR.
+ if (isa<InlineAsm>(Callee))
+ return false;
+
// The reason we include malloc/free here is to exclude the malloc/free
// calls generated in setjmp prep / cleanup routines.
Function *SetjmpF = M.getFunction("setjmp");
Modified: llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll?rev=364985&r1=364984&r2=364985&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll (original)
+++ llvm/trunk/test/CodeGen/WebAssembly/lower-em-sjlj.ll Tue Jul 2 17:37:49 2019
@@ -188,6 +188,27 @@ entry:
; CHECK-NEXT: call void @emscripten_longjmp_jmpbuf(%struct.__jmp_buf_tag* %[[ARRAYDECAY]], i32 5) #1
}
+; Test inline asm handling
+define hidden void @inline_asm() #0 {
+; CHECK-LABEL: @inline_asm
+entry:
+ %env = alloca [1 x %struct.__jmp_buf_tag], align 16
+ %arraydecay = getelementptr inbounds [1 x %struct.__jmp_buf_tag], [1 x %struct.__jmp_buf_tag]* %env, i32 0, i32 0
+ %call = call i32 @setjmp(%struct.__jmp_buf_tag* %arraydecay) #4
+ %cmp = icmp eq i32 %call, 0
+ br i1 %cmp, label %if.then, label %if.else
+
+if.then: ; preds = %entry
+; CHECK: call void asm sideeffect "", ""()
+ call void asm sideeffect "", ""()
+ %arraydecay1 = getelementptr inbounds [1 x %struct.__jmp_buf_tag], [1 x %struct.__jmp_buf_tag]* %env, i32 0, i32 0
+ call void @longjmp(%struct.__jmp_buf_tag* %arraydecay1, i32 1) #5
+ unreachable
+
+if.else: ; preds = %entry
+ ret void
+}
+
declare void @foo()
; Function Attrs: returns_twice
declare i32 @setjmp(%struct.__jmp_buf_tag*) #0
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