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Allow empty assembly string literal with -fno-gnu-inline-asm 

Empty assembly string will not introduce assembly code in the output
binary and it is often used as a trick in the header to disable
optimizations. It doesn't conflict with the purpose of the option so it
is allowed with -fno-gnu-inline-asm flag.

llvm-svn: 237073
This commit is contained in:
Steven Wu 2015-05-12 00:16:37 +00:00
parent 0ddaf2bfb9
commit 18bbe191cd
3 changed files with 21 additions and 8 deletions
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13
clang/lib/Parse/ParseStmtAsm.cpp
View File

@ -616,10 +616,6 @@ StmtResult Parser::ParseAsmStatement(bool &msAsm) {
return ParseMicrosoftAsmStatement(AsmLoc);
}
// Check if GNU-style inline Asm is disabled.
if (!getLangOpts().GNUAsm)
Diag(AsmLoc, diag::err_gnu_inline_asm_disabled);
DeclSpec DS(AttrFactory);
SourceLocation Loc = Tok.getLocation();
ParseTypeQualifierListOpt(DS, AR_VendorAttributesParsed);
@ -644,6 +640,15 @@ StmtResult Parser::ParseAsmStatement(bool &msAsm) {
T.consumeOpen();
ExprResult AsmString(ParseAsmStringLiteral());
// Check if GNU-style InlineAsm is disabled.
// Error on anything other than empty string.
if (!(getLangOpts().GNUAsm || AsmString.isInvalid())) {
const auto *SL = cast<StringLiteral>(AsmString.get());
if (!SL->getString().trim().empty())
Diag(Loc, diag::err_gnu_inline_asm_disabled);
}
if (AsmString.isInvalid()) {
// Consume up to and including the closing paren.
T.skipToEnd();

13
clang/lib/Parse/Parser.cpp
View File

@ -670,12 +670,17 @@ Parser::ParseExternalDeclaration(ParsedAttributesWithRange &attrs,
SourceLocation StartLoc = Tok.getLocation();
SourceLocation EndLoc;
// Check if GNU-style InlineAsm is disabled.
if (!getLangOpts().GNUAsm)
Diag(StartLoc, diag::err_gnu_inline_asm_disabled);
ExprResult Result(ParseSimpleAsm(&EndLoc));
// Check if GNU-style InlineAsm is disabled.
// Empty asm string is allowed because it will not introduce
// any assembly code.
if (!(getLangOpts().GNUAsm || Result.isInvalid())) {
const auto *SL = cast<StringLiteral>(Result.get());
if (!SL->getString().trim().empty())
Diag(StartLoc, diag::err_gnu_inline_asm_disabled);
}
ExpectAndConsume(tok::semi, diag::err_expected_after,
"top-level asm block");

3
clang/test/Parser/no-gnu-inline-asm.c
View File

@ -5,8 +5,11 @@ asm ("INST r1, 0"); // expected-error {{GNU-style inline assembly is disabled}}
void foo() __asm("__foo_func"); // AsmLabel is OK
int foo1 asm("bar1") = 0; // OK
asm(" "); // Whitespace is OK
void f (void) {
long long foo = 0, bar;
asm volatile("INST %0, %1" : "=r"(foo) : "r"(bar)); // expected-error {{GNU-style inline assembly is disabled}}
asm (""); // Empty is OK
return;
}