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tpm.c: Don't try to put -1 in a variable of type TpmModel

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The TpmModel type is an enum (valid values 0 and 1), which means
the compiler can legitimately decide that comparisons like
'tpm_models[i] == -1' are never true. (For example it could
pick 'unsigned char' as its type for representing the enum.)

Avoid this issue by using TPM_MODEL_MAX to mark entries in
the tpm_models[] array which aren't filled in, instead of -1.

This silences a clang warning:

 tpm.c:43:27: error: comparison of constant -1 with expression of type
      'enum TpmModel' is always false [-Werror,-Wtautological-constant-out-of-range-compare]
        if (tpm_models[i] == -1) {
            ~~~~~~~~~~~~~ ^  ~~

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1375096931-13842-1-git-send-email-peter.maydell@linaro.org
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Peter Maydell 2013-07-29 12:22:11 +01:00 committed by Anthony Liguori
parent 125ee0ed9c
commit 8cdd2e0abb
1 changed files with 2 additions and 2 deletions
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tpm.c
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@ -32,7 +32,7 @@ static TPMDriverOps const *be_drivers[TPM_MAX_DRIVERS] = {
};
static enum TpmModel tpm_models[TPM_MAX_MODELS] = {
-1,
TPM_MODEL_MAX,
};
int tpm_register_model(enum TpmModel model)
@ -40,7 +40,7 @@ int tpm_register_model(enum TpmModel model)
int i;
for (i = 0; i < TPM_MAX_MODELS; i++) {
if (tpm_models[i] == -1) {
if (tpm_models[i] == TPM_MODEL_MAX) {
tpm_models[i] = model;
return 0;
}