[cfe-commits] r66528 - /cfe/trunk/lib/CodeGen/CGStmt.cpp

[Chris Lattner]

Author: lattner
Date: Tue Mar 10 00:39:21 2009
New Revision: 66528

URL: http://llvm.org/viewvc/llvm-project?rev=66528&view=rev
Log:
Expand %= into ${:uid} so that the code generator emits a unique ID for the
asm.  This allows us to properly handle the case when an optimizer duplicates
the asm, such as here:

void bar() {
  int i;
  for (i = 0; i < 3; ++i)
    asm("foo %=" : : "r"(0));
}

we now produce:

_bar:
	xorl	%eax, %eax
	## InlineAsm Start
	foo 0
	## InlineAsm End
	## InlineAsm Start
	foo 1
	## InlineAsm End
	## InlineAsm Start
	foo 2
	## InlineAsm End
	ret

instead of:

_bar:
	xorl	%eax, %eax
	## InlineAsm Start
	foo 1
	## InlineAsm End
	## InlineAsm Start
	foo 1
	## InlineAsm End
	## InlineAsm Start
	foo 1
	## InlineAsm End
	ret

This also fixes a fixme by eliminating a static.


Modified:
    cfe/trunk/lib/CodeGen/CGStmt.cpp

Modified: cfe/trunk/lib/CodeGen/CGStmt.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGStmt.cpp?rev=66528&r1=66527&r2=66528&view=diff

==============================================================================
--- cfe/trunk/lib/CodeGen/CGStmt.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGStmt.cpp Tue Mar 10 00:39:21 2009
@@ -714,10 +714,6 @@
   
   unsigned NumOperands = S.getNumOutputs() + S.getNumInputs();
   
-  // FIXME: Static counters are not thread safe or reproducible.
-  static unsigned AsmCounter = 0;
-  AsmCounter++;
-  
   while (*Start) {
     switch (*Start) {
     default:
@@ -729,10 +725,8 @@
     case '%':
       // Escaped character
       Start++;
-      if (!*Start) {
-        // FIXME: This should be caught during Sema.
-        assert(0 && "Trailing '%' in asm string.");
-      }
+      // FIXME: This should be caught during Sema.
+      assert(*Start && "Trailing '%' in asm string.");
       
       char EscapedChar = *Start;
       if (EscapedChar == '%') {
@@ -740,7 +734,7 @@
         Result += '%';
       } else if (EscapedChar == '=') {
         // Generate an unique ID.
-        Result += llvm::utostr(AsmCounter);
+        Result += "${:uid}";
       } else if (isdigit(EscapedChar)) {
         // %n - Assembler operand n
         char *End;
@@ -823,8 +817,7 @@
 static std::string SimplifyConstraint(const char* Constraint,
                                       TargetInfo &Target,
                                       const std::string *OutputNamesBegin = 0,
-                                      const std::string *OutputNamesEnd = 0)
-{
+                                      const std::string *OutputNamesEnd = 0) {
   std::string Result;
   
   while (*Constraint) {
@@ -862,8 +855,7 @@
 llvm::Value* CodeGenFunction::EmitAsmInput(const AsmStmt &S,
                                            TargetInfo::ConstraintInfo Info, 
                                            const Expr *InputExpr,
-                                           std::string &ConstraintStr)
-{
+                                           std::string &ConstraintStr) {
   llvm::Value *Arg;
   if ((Info & TargetInfo::CI_AllowsRegister) ||
       !(Info & TargetInfo::CI_AllowsMemory)) {